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dwx-tx的小天地

Runtime类

Runtime类用于表示java虚拟机运行时的状态，它用于封装java虚拟机进程。

通过getRuntime( )方法获取与之相关的Runtime对象

avaiProcessors( )方法和freeMemory( )方法和maxMemory()方法

代码实例：

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package page03;
import java.io.IOException;
public class Strinh {
    public static void main(String[] args) throws IOException, InterruptedException {
        /*表示java虚拟机运行时的状态*/
        /*Runtime类中提供】一个exec()方法，这个方法执行DOS命令*/
        Runtime rt = Runtime.getRuntime();
        /*availablePracessors()方法用来获得处理器的个数*/
        /*freeMemory()方法用来获得空闲内存大小*/
        /*maxMemory用来获得最大可用内存大小*/
        System.out.println("处理器的个数:"+rt.availableProcessors()+"个");
        System.out.println("空闲内存大小:"+rt.freeMemory()/1024/1024+"M");
        System.out.println("最大可用内存大小"+rt.maxMemory()/1021/1024+"M");
        Process process = rt.exec("notepad.exe");
        Thread.sleep(3000);
        process.destroy();

    }
}

语法格式：

Runtime run = Runtime.getRuntime();

exec( )方法

Runtime类中提供了一个exec( )方法，该方法用于执行一个DOS命令，从而实现和命令框中输入DOS命令相同的效果

destroy( )方法

Runtime类中提供的destroy( )方法，是用来关闭打开的文件

System类

System类的常用方法

方法说明 功能描述
static void exit(int status) 该方法用来终止当前正在运行的java虚拟机，其中参数static表示状态码，若状态码非0，则表示异常终止
static void gc() 运行垃圾回收器，并对垃圾进行回收（只是提醒虚拟机进行回收，实际不知道是否真的回收）
static native long currentTimeMillis() 返回以毫秒为单位的当前时间
static void arraycopy(Object src,int srcPos,Object dest,int destPos,int length) 从src引用的指定源数组拷贝到dest引用的数组，拷贝从指定的位置开始，到目标数组的指定位置结束
static Properties getProperties() 取得当前的系统属性
static String getProperty(String key) 获取指定键描述的系统属性

getProprety()方法

getProprety方法用于获取当前系统的全部属性，该方法会返回一个Propreties对象，其中封装了系统的所有属性，这些属性是以键值对的形式存在。

代码示例：

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package page03;

import java.util.Properties;
import java.util.Set;

public class System01 {

    public static void main(String[] args) {
        Properties pr = System.getProperties();
        System.out.println(pr);
        Set<String>propertyNames = pr.stringPropertyNames();
        for(String key:propertyNames){
            String value = System.getProperty(key);
            System.out.println(key+"---->"+value);
        }

    }
}

currentTimeMills()

currentTimeMills()方法返回一个long类型的值,表示当时时间与1970年1月1日0点0分0秒之间的差，单位是毫秒，通常也将该值称作时间戳。

两个时间戳之差能够求出程序的运行时间

代码实例:

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public class currentTimeMills01 {
    public static void main(String[] args) {
        long startTime = System.currentTimeMillis();
        int  sum=0;
        for(int i=0;i<1000000000;i++){
            sum=sum+i;
        }
        long endTime = System.currentTimeMillis();
        System.out.println("程序的运行时间为："+(endTime-startTime)+"毫秒");

    }
}

arraycopy(Object src,int srcPos,Object dest,int destPos,int length)

  • src：表示源数组
  • dest：表示目标数组
  • srcPos：表示原数组中拷贝元素的起始位置
  • destPos：表示拷贝到目标元素的起始位置
  • length：表示拷贝元素的个数

java构造器详解

定义

类的构造器也称为构造方法，是在进行创建对象的时候必须要调用的。

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package way;
class Person{
    //一个类及时什么也不写，他也会存在一个方法
    String name;
    //构造器第一个功能:实例化一些初始值
    //使用new关键字，必须使用构造器
    //无参构造
    //Alt + insert可以直接生成构造器


    public Person() {
    }



    //有参构造,一旦使用有参构造，就必须显示定义无参构造
    public Person(String name){
        this.name = name;
    }

}

public class way03 {
    public static void main(String[] args) {
        //用new关键词声明了一个person对象
        Person person = new Person("XXX");
        System.out.println(person.name);
    }

}

构造器的特点

  • 构造器的名字必须和类的名字相同
  • 构造器必须没有返回类型，也不能写void
  • 使用new关键字，必须使用构造器
  • 一个类及时什么也不写，他也会存在一个方法

注释：可以通过java.class文件可以发现其中有一个方法

构造器的作用

  • 构造器第一个功能:实例化一些初始值
  • 使用new关键字，必须使用构造器

构造器的方便构造

Alt + insert可以直接生成构造器

计算器原始代码（面向过程）

计算器原始代码（面向过程）

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package com.dwx.Prame;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class testCale {
    public static void main(String[] args) {
        new Cale();
    }
}
class Cale extends Frame{
    public Cale(){
        //在窗口上 我们需要三个文本框 一个标签 一个按钮
        TextField num1 = new TextField(10);
        TextField num2 = new TextField(10);
        TextField num3 = new TextField(11);

        Label label = new Label("+");

        Button button = new Button("=");
        button.addActionListener(new MyCale(num1,num2,num3)); //将三个文本框作为参数传递给下边的方法
        //流式布局
        setLayout(new FlowLayout());
        add(num1);
        add(label);
        add(num2);
        add(button);
        add(num3);
        pack();
        setVisible(true);
        addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(0);
            }
        });

    }

}
class MyCale implements ActionListener{

    //获取三个变量
    //将第三个变量的值设为前两个变量的和
    //将前两个变量清空
    private TextField num1,num2,num3; //设置三个本地的参数来承接传递过来的参数
    public  MyCale(TextField num1,TextField num2,TextField num3){
            this.num1 = num1;
            this.num2 = num2;
            this.num3 = num3;

    }
    @Override
    public void actionPerformed(ActionEvent e) {
        int n1 = Integer.parseInt(num1.getText());//将字符串类型强制转换成int类型的方法
        int n2 = Integer.parseInt(num2.getText());

        num3.setText(""+(n1+n2));

        num1.setText("");
        num2.setText("");

    }
}

Random类

在math中有random()方法，但是，java还提供类一个Random类，这些类能够提供更加丰富多样的随机数

Random的构造方法

方法说明 功能描述
Random( ) 用于创建一个随机数生成器，每次实例化Random对象会产生不同的随机数
Random(long seed) 使用一个long类型的seed种子，当seed相同时，每次Random实例会生成相同的随机数

与C语言不同的是，Random( )方法中种子是随机给出的

Random类的常用方法

方法声明 功能描述
boolean nextBoolean() 随机生成boolean类型随机数
double nextDouble() 随机生成double类型的随机数
float nextFloat() 随机生成float类型的随机数
int nextInt() 随机生成int类型的随机数
int nextInt(n) 随机生成从[0,n)之间int类型的随机数
long nextLong() 随机生成long类型的随机数

代码实例：

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package page03;

import java.util.Random;

public class Random01 {
    public static void main(String[] args) {
        Random r = new Random();
        System.out.println("这是一个随机的boolean类型的随机数"+r.nextBoolean());
        System.out.println("这是一个int类型的随机数"+r.nextInt());
        System.out.println("这是一个double类型的随机数"+r.nextDouble());
        System.out.println("这一个float类型的随机数"+r.nextFloat());
        System.out.println("这是一个产生从0~10的int类型的随机数"+r.nextInt(10));
        System.out.println("这是一个产生long类型的随机数"+r.nextLong());

    }
}

JdbcUtils

JdbcUtils

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package com.dwx.jabcstudy;

import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

public class JdbcUtils {
    //提升作用域
    private static String driver = null;
    private static String url = null;
    private static String username = null;
    private static String password = null;
    // 这是一个静态代码块 因此 再倒入这个类时 只会加载一次
    static {
        try{
            InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("db.properties"); //这里是去获取配置文件
            Properties properties = new Properties(); //这是一个流
            properties.load(in); //加载配置文件
           driver = properties.getProperty("driver");//这就是获取配置文件中数值的方法
           url =  properties.getProperty("url");
           username =  properties.getProperty("username");
           password =  properties.getProperty("password");
           Class.forName(driver);//加载mysql
        }catch (Exception e){
            System.out.println("出错了!!!");
        }finally {

        }
    }
    //获取链接
    //方法会返回一个Connection类型的数据
    public static Connection getConnection() throws Exception {
        return DriverManager.getConnection(url, username, password);
    }
    //释放资源
    public static void release(Connection connection, Statement statement, ResultSet resultSet) throws SQLException {
        if(resultSet!=null){
            try {
                resultSet.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(statement!=null){
            statement.close();
        }
        if (connection!=null){
            connection.close();
        }
    }
}

注意：这个JdbcUtils工具类需要放在调用它的类的同一个包下

db.properties

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driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/demo?useUnicode=true&characterEnconding=utf8&useSSL=true
username=dwx
password=123456

注意：这个配置需要放在src目录下

操作实例

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package com.dwx.jabcstudy;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCSecond {
    public static void main(String[] args) throws Exception {
        Connection connection = null;
        Statement statement = null;
        ResultSet resultSet = null;
        try {
            connection = JdbcUtils.getConnection();//获取数据库链接
            statement = connection.createStatement();//获得sql的执行对象
            String sql = "INSERT INTO dwx(id,`name`,`sex`)" +
                    "VALUES(6,'kti','m')"; //有了sql命令
            int i = statement.executeUpdate(sql);//将sql丢到sql执行对象里边就行了
            if(i>0){
                System.out.println("插入成功!!!");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            JdbcUtils.release(connection,statement,resultSet); //调用工具类来释放资源
        }

    }
}

servlet优化

servlet web.tml配置 以及 maven servlet jsp依赖

servlet web.tml配置

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<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                      http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0"
         metadata-complete="true">
 </web-app>

maven servlet jsp依赖

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 <!--servlet依赖-->
 <dependency>
      <groupId>jakarta.servlet</groupId>
      <artifactId>jakarta.servlet-api</artifactId>
      <version>5.0.0</version>
      <scope>provided</scope>
</dependency>
   
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<dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
            <scope>provided</scope>
</dependency>

实现SMBMS

实现SMBMS

实现这个SMBMS用到了包括servlet jsp jstl standard mysql等的依赖

由于Tomcat版本过高原因，javax已经不再适用 而替换成了jakarta

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<!--jsp的依赖-->
    <dependency>
      <groupId>jakarta.servlet.jsp</groupId>
      <artifactId>jakarta.servlet.jsp-api</artifactId>
      <version>3.0.0</version>
      <scope>provided</scope>
    </dependency>

    <!--jar包的依赖-->
    <dependency>
      <groupId>jakarta.servlet</groupId>
      <artifactId>jakarta.servlet-api</artifactId>
      <version>5.0.0</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <!--这个项目里我自己倒的包-->
    <!--servlet 5.0-->
    <!--servlet依赖-->
    <dependency>
      <groupId>jakarta.servlet</groupId>
      <artifactId>jakarta.servlet-api</artifactId>
      <version>5.0.0</version>
      <scope>provided</scope>
    </dependency>
    <!--jsp2.2-->
    <!--mysql依赖-->
    <!-- https://mvnrepository.com/artifact/org.wisdom-framework/mysql-connector-java -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.27</version>
    </dependency>
  <!--standard-->
    <!-- https://mvnrepository.com/artifact/taglibs/standard -->
    <dependency>
      <groupId>taglibs</groupId>
      <artifactId>standard</artifactId>
      <version>1.1.2</version>
    </dependency>
    <dependency>
      <groupId>org.glassfish.web</groupId>
      <artifactId>jakarta.servlet.jsp.jstl</artifactId>
      <version>2.0.0</version>
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>
    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.2</version>
      <scope>provided</scope>
    </dependency>
      <dependency>
          <groupId>org.junit.jupiter</groupId>
          <artifactId>junit-jupiter</artifactId>
          <version>RELEASE</version>
          <scope>compile</scope>
      </dependency>
    <dependency>
      <groupId>org.testng</groupId>
      <artifactId>testng</artifactId>
      <version>RELEASE</version>
      <scope>compile</scope>
    </dependency>

为banksystem增加一个用户注册操作

前端代码

enroll界面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/12/7
  Time: 22:32
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>注册</title>
    <style type="text/css">
        body{background-color: #F5DEB3;}
        div{
            position: absolute;
            top: 200px;
            left: 580px;
            border-radius: inherit;
        }
    </style>
</head>
<body>
<!--对于祖册功能 其实就是一个表单-->
<div>
    <h1>注册界面</h1>
    <form action="login" method="post">
        <h2>请输入用户id:<input type="text" name="id"/></h2>
        <h2>请输入密码:&nbsp;&nbsp;&nbsp;<input type="text" name="password"></h2>
        <h2>请输入用户姓名:<input type="text" name="username"></h2>
        <input type="reset" value="重置">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input type="submit" value="enroll" name="method">
    </form>
</div>
</body>
</html>

enrollsuccess界面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 9:41
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>注册成功</title>
</head>
<body>
<a href="login.jsp"><h1>注册成功，请点击重新登录</h1></a>
</body>
</html>

enrollError界面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 9:42
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>注册失败</title>
</head>
<body>
<a href="login.jsp"><h1>注册失败，用户ID已存在，请点击重新注册</h1></a>
</body>
</html>

后端代码

userDao层

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@Override
   public boolean enroll(String ID, String password, String userName) throws SQLException {
       //预编译sql 在预编译SQL前 必须判断是否已经有人使用过这个ID了 因为这个银行操作系统不可能出现相同的id
       //先通过查询 岔开是否数据库里已经有个这个ID
       PreparedStatement pstm = null;
       ResultSet resultSet = null;
       boolean flag = false;
       //对于刚开户的用户 其余额理应是0
       double money = 0;
       //预编译SQL
       String sql = "SELECT * FROM bank_system WHERE ID = ?";
       //编写这个Sql查询需要的参数
       Object[] Params = {ID};
       //调用BaseDao层进行查询，查看查询结果
       Connection connection ;
       connection = BaseDao.getConnection();
       try {
           resultSet = BaseDao.exectue(connection, pstm, resultSet, sql, Params);
       } catch (Exception e) {
           e.printStackTrace();
       }
       //如果查询结果不为空 那么说明在数据库里已经存在了这个数据 直接返回创建失败
       if (resultSet.next()) {
           return false;
       } else {
           //如果没有ID，就继续向下执行
           //编写创建成员的sql
           PreparedStatement pstm1 = null;
           Connection connection1 ;
           connection1 = BaseDao.getConnection();
           //预编译sql
           String sql1 = "INSERT INTO bank_system(ID,PASSWORD,username,money)\n" +
                   "VALUES(?,?,?,?)";
           Object[] params = {ID, password, userName, money};
           //调用BaseDao来操作数据
           try {
               int flag1 = BaseDao.exectue(connection1, pstm1, sql1, params);
               //如果返回非0 这说明创建成功
               if (flag1 != 0) {
                   flag = true;
               } else {
                   flag = false;
               }


           } catch (Exception e) {
               e.printStackTrace();
           }
       }
       //在使用晚资源后 及时关闭所有资源
       try {
           BaseDao.closeResource(connection,pstm,resultSet);
       } catch (Exception e) {
           e.printStackTrace();
       }
       System.out.println(flag);
       return flag;
   }

userService层

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@Override
   public boolean enroll(String ID, String password, String username) {
       boolean flag = false;
       System.out.println("执行到了service层");
       userDaoimp userDaoimp = new userDaoimp();
       try {
           flag = userDaoimp.enroll(ID, password, username);
       } catch (SQLException throwables) {
           throwables.printStackTrace();
       }
       System.out.println("service");
       return flag;
   }

servlet层

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public void enroll(HttpServletRequest req,HttpServletResponse resp){
        boolean flag = false;
        String ID = req.getParameter("id");
        String password = req.getParameter("password");
        String username = req.getParameter("username");
        System.out.println(ID);
        System.out.println(password);
        System.out.println(username);
        userServiceImp userServiceImp = new userServiceImp();
        flag = userServiceImp.enroll(ID,password,username);
        if (flag){
            try {
                resp.sendRedirect("enrollsuccess.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }else {
            try {
                resp.sendRedirect("enrollerror.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }public void enroll(HttpServletRequest req,HttpServletResponse resp){
        boolean flag = false;
        String ID = req.getParameter("id");
        String password = req.getParameter("password");
        String username = req.getParameter("username");
        System.out.println(ID);
        System.out.println(password);
        System.out.println(username);
        userServiceImp userServiceImp = new userServiceImp();
        flag = userServiceImp.enroll(ID,password,username);
        if (flag){
            try {
                resp.sendRedirect("enrollsuccess.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }else {
            try {
                resp.sendRedirect("enrollerror.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
     }

title: java课程大作业 银行操作系统

使用javaweb 实现前端和数据库的交互

前端资源

我自己写的前端资源是十分简单的 简约的 以HTML为主 简单的css 并没有JavaScript。使用的是.jsp

来实现前后端交互

登录界面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 8:59
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>login</title>
    <style type="text/css">
        h1{align-content: center;text-align: center;}
        body{background-color:wheat}
        #login{

            width: 280px;
            height: auto;
            background-color:wheat;

            position: fixed;
            top:  260px;
            left: 600px;

            border-width: 10px;
            border-style: solid;
            border-color:wheat;
        }
        #reset{
            position: fixed;
            top: 400px;
            left: 620px;
        }
        #login1{
            position: fixed;
            top: 400px;
            left: 820px;
        }
        #title{
            position: fixed;
            top: 180px;
            left: 640px;

        }

    </style>

</head>
<body>
<!--action接的是登录的servlet-->
<div>
    <div>
        <h1 id="title">银行系统登录</h1>
    </div>
    <div id="login">
        <form method="post" action="login">
            <h4>银行卡号:<input type="text" name="id"/><br/></h4>
            <h4>银行密码:<input type="password" name="password"/><br/></h4>
            <input id="login1" type="submit" value="login" name="method">

            <input id="reset" type="reset" value="重置">
        </form>
    </div>
</div>
</body>
</html>

登录失败页面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 9:22
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>ERROR</title>
</head>
<body>
<a href="login.jsp"><h1>用户名或密码错误，点击重新登录</h1></a>
</body>
</html>

操作页面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 9:25
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>操作界面</title>

    <style type="text/css">
        body{
            background-color: #F5DEB3;
        }
        #center{
            width: 260px;
            position: absolute;
            top: 200px;
            left: 580px;
            border-radius: inherit;
        }
        .button{
            align-self: center;
        }

    </style>
</head>
<body>
<!--头部的div-->
<div id="head">
    <h1 align="center">操作界面</h1>
</div>
<div id="center">
    <form method="post" action="login">
        <h2 align="center">欢迎您${username}</h2>
        <a href="in.jsp"><input type="button"  value="存钱"></a><br/>
        <a href="get.jsp"><input type="button" value="取钱"></a><br/>
        <a href="view.jsp"><input type="button"  value="查看余额"><br/></a>
        <a href="changepassword.jsp"><input type="button"  value="修改密码"><br/></a>
        <input type="submit"  name="method" value="layout"><br/>
    </form>
</div>


</body>
</html>


取钱页面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 9:26
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>取钱操作</title>
    <style>
        body{
            background-color: #F5DEB3;
        }
        div{
            width: 300px;
            background-color: #F5DEB3;
            position: absolute;
            top: 200px;
            left: 580px;
        }
    </style>
</head>
<body>
<div>
    <h1>取款</h1>
    <form method="post" action="login">
        <h2>取钱金额:<input type="text" name="moneyin"></h2>
        <input type="reset" value="重置">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input id="click" type="submit" name="method" value="get">
    </form>
</div>
</body>
</html>

取钱失败页面 / 取钱成功页面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 9:42
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>取钱失败</title>
</head>
<body>
<a href="service.jsp"><h1>取钱失败，余额不足，点击跳转到操作页面</h1></a>
</body>
</html>

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 9:41
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>取钱成功</title>
</head>
<body>
<a href="service.jsp"><h1>取钱成功，点击跳转到操作页面</h1></a>
</body>
</html>

存钱界面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 10:16
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>存钱操作</title>
    <style>
        body{
            background-color: #F5DEB3;
        }
        div{
            width: 300px;
            background-color: #F5DEB3;
            position: absolute;
            top: 200px;
            left: 580px;
        }
    </style>
</head>
<body>
<div>
    <h1>存款</h1>
    <form method="post" action="login">
        <h2>存储金额:<input type="text" name="moneyin"></h2>
        <input type="hidden" name="moneyin">
        <input type="reset" value="重置">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input id="click" type="submit" name="method" value="in">
    </form>
</div>
</body>
</html>
<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 10:16
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>存钱操作</title>
    <style>
        body{
            background-color: #F5DEB3;
        }
        div{
            width: 300px;
            background-color: #F5DEB3;
            position: absolute;
            top: 200px;
            left: 580px;
        }
    </style>
</head>
<body>
<div>
    <h1>存款</h1>
    <form method="post" action="login">
        <h2>存储金额:<input type="text" name="moneyin"></h2>
        <input type="hidden" name="moneyin">
        <input type="reset" value="重置">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input id="click" type="submit" name="method" value="in">
    </form>
</div>
</body>
</html>

存钱成功界面/存钱失败页面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 10:22
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>存钱成功</title>
</head>
<body>
<a href="service.jsp"><h1>存钱成功，点击跳转到操作页面</h1></a>
</body>
</html>

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 10:23
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>存钱失败</title>
</head>
<body>
<a href="service.jsp"><h1>存钱失败，点击跳转到操作页面</h1></a>
</body>
</html>

修改密码页面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 10:45
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>修改密码</title>
    <style type="text/css">
        body{
            background-color: #FAEBD7;
        }
        div{
            position: absolute;
            top: 200px;
            left: 600px;
        }
    </style>
</head>
<body>
<div>
    <h1>修改密码</h1>
    <form action="login" method="post">
        <h3>请输入旧密码:<input type="text" name="oldpassword"></h3>
        <h3>请输入新密码:<input type="text" name="newpassword"></h3>
        <input type="submit" value="重置"/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input type="submit" value="change" name="method"/>
    </form>
</div>
</body>
</html>

修改密码成功页面 / 修改密码失败页面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 10:52
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>修改密码成功</title>
</head>
<body>
<a href="login.jsp"><h1>修改密码成功，请点击重新登陆</h1></a>
</body>
</html>

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 10:51
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>修改密码失败</title>
</head>
<body>
<a href="changepassword.jsp"><h1>旧密码错误，点击重新输入</h1></a>
</body>
</html>

查看余额页面

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<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/11/30
  Time: 10:11
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>查看存款</title>
    <style type="text/css">
        body{
            background-color: antiquewhite;

        }
        div{
            position: absolute;
            top: 200px;
            left: 600px;
        }
    </style>
</head>
<body>
<div>
    <h1>查看存款</h1>
    <form action="login" method="post">
        <h2>客户${username}，您的存款数目为${money}元</h2><br/>
        <a href="service.jsp"><h4>点击返回到操作页面</h4></a>
    </form>
</div>
</body>
</html>


后端代码

所有的依赖

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<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>BankSystem</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>BankSystem Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <!--mysql依赖-->
    <!-- https://mvnrepository.com/artifact/org.wisdom-framework/mysql-connector-java -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.27</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.1</version>
      <scope>provided</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet.jsp/javax.servlet.jsp-api -->
    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>javax.servlet.jsp-api</artifactId>
      <version>2.3.3</version>
      <scope>provided</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.taglibs/taglibs-standard-impl -->
    <dependency>
      <groupId>org.apache.taglibs</groupId>
      <artifactId>taglibs-standard-impl</artifactId>
      <version>1.2.5</version>
      <scope>runtime</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/javax.servlet.jsp.jstl/jstl -->
    <dependency>
      <groupId>javax.servlet.jsp.jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>
    <dependency>
      <groupId>xml-apis</groupId>
      <artifactId>xml-apis</artifactId>
      <version>1.3.04</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.taglibs/taglibs-standard-impl -->
    <dependency>
      <groupId>org.apache.taglibs</groupId>
      <artifactId>taglibs-standard-impl</artifactId>
      <version>1.2.5</version>
      <scope>runtime</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter-api -->
    <dependency>
      <groupId>org.junit.jupiter</groupId>
      <artifactId>junit-jupiter-api</artifactId>
      <version>5.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.testng</groupId>
      <artifactId>testng</artifactId>
      <version>RELEASE</version>
      <scope>compile</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
    <dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>1.4</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
    <dependency>
      <groupId>commons-io</groupId>
      <artifactId>commons-io</artifactId>
      <version>2.11.0</version>
    </dependency>


  </dependencies>

  <build>
    <finalName>BankSystem</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

web.xml

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<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                      http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0"
         metadata-complete="true">
    <welcome-file-list>
        <welcome-file>/login.jsp</welcome-file>
    </welcome-file-list>
    <servlet>
        <servlet-name>login</servlet-name>
        <servlet-class>com.dwx.servlet.customerServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>login</servlet-name>
        <url-pattern>/login</url-pattern>
    </servlet-mapping>
</web-app>

后端代码

DAO层

basedao

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package com.dwx.dao;

import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

//这是一个最基础的Dao类 是用来和数据库进行交互的
//通过分析 我们需要用到的jdbc操作 包括 查 改
public class BaseDao {
    //获取和数据库的联结
    public static String driver;
    public static String url;
    public static String username;
    public static String password;
    //通过重定向 到db.propertries中获取到数据
    //定义的static参数 通过static代码块 对其进行初始化
    static{
        InputStream stream = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
        Properties properties = new Properties();
        try {
            properties.load(stream);
        } catch (IOException e) {
            e.printStackTrace();
        }
        driver = properties.getProperty("driver");
        url = properties.getProperty("url");
        username = properties.getProperty("username");
        password = properties.getProperty("password");
    }
    //与数据库进行链接
    public static Connection getConnection(){
        Connection connection = null;
        try {
            Class.forName(driver);
            connection = DriverManager.getConnection(url, username, password);
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }

        return connection;
    }
    //创建用于改的execute
    //编写查询公共类
    public static ResultSet exectue(Connection connection, PreparedStatement prepareStatement, ResultSet resultSet, String sql, Object[] params) throws Exception {
        try {
            prepareStatement = connection.prepareStatement(sql);
            //不清楚这里的prepareStatement与setStatement有啥区别
            //prepareStream是预编译 是解决数据库泄露问题时讲过的
            for (int i = 0; i < params.length; i++) {
                prepareStatement.setObject(i + 1, params[i]);
            }
        } catch (Exception throwables) {
            throwables.printStackTrace();
        }
        resultSet = prepareStatement.executeQuery();
        return resultSet;
    }

    //增删改公共方法
    public static int exectue(Connection connection,PreparedStatement prepareStatement,String sql,Object[] params) throws Exception {
        try {
            prepareStatement = connection.prepareStatement(sql);
            //不清楚这里的prepareStatement与setStatement有啥区别
            for (int i=0;i<params.length;i++){
                prepareStatement.setObject(i+1,params[i]);
            }
        } catch (Exception throwables) {
            throwables.printStackTrace();
        }
        int updataRows = prepareStatement.executeUpdate();
        return  updataRows;


    }
    //释放资源
    public static boolean closeResource(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet) throws Exception {
        boolean flag=true;
        if (resultSet!=null){
            resultSet.close();
            resultSet = null;
        }
        if (preparedStatement!=null){
            preparedStatement.close();
            preparedStatement=null;
        }
        if (connection!=null){
            connection.close();
        }
        return flag;

    }

}

monyDao

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package com.dwx.dao.money;

import java.sql.SQLException;

public interface moneyDao {
    //对于金钱的操作有三种 产看余额 存款 取款
    //查看余额 就是一个查询语句 返回值是int类型 money
    //通过 ID 和 Password来获得余额
    double getMoney(String ID,String password) throws SQLException;
    //存取款 ID password moneyIn
    boolean changeMoney(String ID,String password,double money,double moneyIn);
}

moneyDaoImp

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package com.dwx.dao.money;

import com.dwx.dao.BaseDao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class moneyDaoImp implements moneyDao {
    @Override
    public double getMoney(String ID, String password) throws SQLException {
        //先进行数据库链接
        Connection connection;
        connection = BaseDao.getConnection();
        double money=0;
        //写预编译sql
        PreparedStatement pstm=null;
        String sql = "SELECT money FROM bank_system WHERE ID = ? AND Password = ?";
        //编写一个参数集 用来传递参数
        Object[] param = {ID,password};
        ResultSet result = null;
        //编写一个resul来获得查询的返回值
        try {
            result = BaseDao.exectue(connection,pstm,result,sql,param);
        } catch (Exception e) {
            e.printStackTrace();
        }
        //得到了result
        if (result.next()){
            money = result.getDouble("money");
        }
        return money;
    }

    @Override
    public boolean changeMoney(String ID, String password,double money,double moneyIn) {
        if (money+moneyIn<0){
            return false;
        }
        boolean flag = false;
        //创建连接
        Connection connection;
        connection = BaseDao.getConnection();
        //编写预编译SQL
        int r = 0;
        PreparedStatement pstm = null;
        String sql = "UPDATE bank_system SET money = ? WHERE ID = ? AND Password = ?";
        //编写param表示参数集
        //这里 用money + moneyIn表示改变后的值 若moneyIn为正 则就是存储 要是负 则是取钱
        Object[] param = {money+moneyIn,ID,password};
        //调用Base进行改值
        try {
            r = BaseDao.exectue(connection,pstm,sql,param);
        } catch (Exception e) {
            e.printStackTrace();
        }
        if (r!=0){
            flag=true;
        }
        System.out.println("Dao"+flag);
        return flag;
    }
}

userDao

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package com.dwx.dao.user;

import java.sql.SQLException;

//这个抽象类 主要是对user进行操作 如 修改密码 增加用户 删除用户 等等
public interface userDao {
    //修改密码 修改密码需要用到 ID 和 old_password 进行比较后才能修改
    //修改密码 返回布尔类型 表示是否修改成功
    boolean changePassword(String ID,String oldPassword,String newPassword);
    //用户登录 就是去数据库查询是否有此人 如有此人 则返回username 需要获得ID，password
    String login(String ID,String password) throws SQLException;

}

userDaoImp

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package com.dwx.dao.user;

import com.dwx.dao.BaseDao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class userDaoimp implements userDao{
    @Override
    public boolean changePassword(String ID, String oldPassword,String newPassword) {
        //获得链接
        boolean flag = false;
        int resultSet = 0;
        Connection connection;
        connection = BaseDao.getConnection();
        //预编译sql
        PreparedStatement pstm = null;
        String sql = "UPDATE bank_system SET Password=? WHERE ID=? AND Password=?";
        //设置sql要插入的参数
        Object[] param = {newPassword,ID,oldPassword};
        try {
            resultSet = BaseDao.exectue(connection,pstm,sql,param);
        } catch (Exception e) {
            e.printStackTrace();
        }
        if (resultSet!=0){
            flag=true;
        }
        //关闭开启的资源
        try {
            BaseDao.closeResource(connection,pstm,null);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return flag;
    }

    @Override
    public String login(String ID, String password) throws SQLException {
        Connection connection;
        //注意 不要忘记connection
        connection = BaseDao.getConnection();
        String username=null;
        //预编译一个SQL 只需要一个SELECT
        PreparedStatement pstm=null;
        //准备一个结果集 这个查询是要获得结果集的
        String sql = "SELECT * From bank_system WHERE ID = ? AND Password = ?";
        //创建一个param参数
        Object[] param = {ID,password};
        //用一个result来存储查询到的结果集
        ResultSet resultSet = null;
        try {
            resultSet = BaseDao.exectue(connection,pstm,resultSet,sql,param);
        } catch (Exception e) {
            e.printStackTrace();
        }
        assert resultSet != null;
        if (resultSet.next()){
            username = resultSet.getString("username");
        }
        return username;
    }
}

POJO

映射类

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package com.dwx.pojo;
//这个类是映射到数据库中bank_system这个表
public class bank_system {
    //创造几个对象 对应数据库中的几个参数
    //设置的都是私有对象 需要通过set和get获取值
    private int ID;
    private String Password;
    private String username;
    private int money;

    public int getID() {
        return ID;
    }

    public void setID(int ID) {
        this.ID = ID;
    }

    public String getPassword() {
        return Password;
    }

    public void setPassword(String password) {
        Password = password;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public int getMoney() {
        return money;
    }

    public void setMoney(int money) {
        this.money = money;
    }
}

service层

userservice

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package com.dwx.service.user;
//对于用户的一些操作

public interface userService {

    //修改用户的密码 修改密码需要得到并传递给dao层 ID（int） newPasswor(String) oldPasswor(String)
    //返回值类型为 boolen
     boolean  changePasswordService(String ID,String oldPassword,String newPassword);
     //登录 需要给Dao ID Password 需要返回给test username
    String login(String ID,String passWord);

}

userserviceImp

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package com.dwx.service.user;

import com.dwx.dao.user.userDaoimp;

import java.sql.SQLException;

public class userServiceImp implements userService{
    @Override
    public  boolean changePasswordService(String ID, String oldPassword, String newPassword) {
        boolean flag;
        userDaoimp daoimp = new userDaoimp();
        flag = daoimp.changePassword(ID,oldPassword,newPassword);
        return flag;
    }

    @Override
    public String login(String ID, String passWord) {
        String username = null;
        userDaoimp daoimp = new userDaoimp();
        try {
            username = daoimp.login(ID,passWord);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return username;
    }
}

servlet层

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package com.dwx.servlet;

import com.dwx.service.money.moneyServiceImp;
import com.dwx.service.user.userServiceImp;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class customerServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
        String method = req.getParameter("method");
        System.out.println(method);
        switch (method) {
            case "login":
                login(req, resp);
                break;
            case "get":
                getmoney(req, resp);
                break;
            case "in":
                insertmoney(req, resp);
                break;
            case "layout":
                logout(req, resp);
                break;
            case "change":
                changepassword(req, resp);
                break;
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp){
        doGet(req, resp);
    }
    public void login(HttpServletRequest req, HttpServletResponse resp){
        String id = req.getParameter("id");
        System.out.println(id);
        String password = req.getParameter("password");
        System.out.println(password);
        double money;
        //用得到的数据进行联结
        userServiceImp userServiceImp = new userServiceImp();
        moneyServiceImp moneyServiceImp = new moneyServiceImp();
        money = moneyServiceImp.getMoney(id,password);
        //登录
        String username = userServiceImp.login(id,password);
        //如果登录成功就跳转到service.jsp页面
        //如果登陆失败 就跳转到error.jsp页面
        if (username==null){
            try {
                resp.sendRedirect("error.jsp");
            } catch (IOException ignored) {

            }
        }else {
            //如果联结成功 就把用户名 账号 密码 都放到session里边 以便其他的程序使用
            req.getSession().setAttribute("id",id);
            req.getSession().setAttribute("password",password);
            req.getSession().setAttribute("username",username);
            req.getSession().setAttribute("money",money);
            try {
                resp.sendRedirect("service.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
    public void getmoney(HttpServletRequest req,HttpServletResponse resp){
        //经过登录操作 已经把id,password,money等数据都存放到session里了 需要的话直接去session里拿
        String id = (String) req.getSession().getAttribute("id");
        String password = (String) req.getSession().getAttribute("password");
        double money = (Double) req.getSession().getAttribute("money");
        System.out.println(id);
        System.out.println(password);
        System.out.println(money);
        //从前端获取要取出的数值 再去service层进行操作
        double moneyin = Double.parseDouble(req.getParameter("moneyin"));
        //设置一个flag来分辨是否取钱成功
        boolean flag;
        moneyServiceImp moneyServiceImp = new moneyServiceImp();
        flag = moneyServiceImp.changeMoney(id,password,money,-moneyin);
        //如果取钱成功 跳转到取钱成功页面
        //取钱成功 及时更改session里的money的值
        req.getSession().setAttribute("money",moneyServiceImp.getMoney(id,password));
        if (flag){
            try {
                resp.sendRedirect("getSuccess.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        //如果取钱失败 跳转到取钱失败页面
        else {
            try {
                resp.sendRedirect("getError.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    public void insertmoney(HttpServletRequest req,HttpServletResponse resp){
        //与取款一样 存款需要从session里边获取数值
        String id = (String) req.getSession().getAttribute("id");
        String password = (String) req.getSession().getAttribute("password");
        double money = (Double) req.getSession().getAttribute("money");
        //再拿到前端输入的需要存款的数值
        double moneyin = Double.parseDouble(req.getParameter("moneyin"));
        //调用service层对数据进行操作哦
        moneyServiceImp moneyServiceImp = new moneyServiceImp();
        //设置一个布尔值 来判断是否操作成功
        boolean flag;
        flag = moneyServiceImp.changeMoney(id,password,money,moneyin);
        if (flag){
            //如果操作成功 跳转到存款成功页面 并且更新session中money的值
            req.getSession().setAttribute("money",moneyServiceImp.getMoney(id,password));
            try {
                resp.sendRedirect("insuccess.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }else {
            //如果没有成功 则跳转到存钱失败页面
            try {
                resp.sendRedirect("inError.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }

        }

    }
    public void logout(HttpServletRequest req, HttpServletResponse resp){
        //退出操作
        //退出操作的具体思路就是 将session里的id和password都换成null并且跳转到登录页面
        req.getSession().setAttribute("id",null);
        req.getSession().setAttribute("password",null);
        try {
            resp.sendRedirect("login.jsp");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public void changepassword(HttpServletRequest req, HttpServletResponse resp){
        //从session里获得数据
        String id = (String) req.getSession().getAttribute("id");
        String password = (String) req.getSession().getAttribute("password");
        //从前端获得数据
        String passwordin = req.getParameter("oldpassword");
        System.out.println(passwordin);
        String newpassword = req.getParameter("newpassword");
        System.out.println(newpassword);
        //如果前端获取的oldpassword与实际的password不同 跳转到Error页面
        //如果通过了 就往下继续执行
        userServiceImp userServiceImp = new userServiceImp();
        //创造一个布尔值来标记是否修改成功
        boolean flag;
        flag = userServiceImp.changePasswordService(id,password,newpassword);
        if (flag)
        {
            //如果修改成功 就跳转到成功页面
            try {
                resp.sendRedirect("changesuccess.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }else {
            //如果没成功就送到失败页面
            try {
                resp.sendRedirect("changeError.jsp");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

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