J2EE知识点1 - 银行系统代码2 - 《Java笔记》

package controller;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
public class TransferController extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String username=req.getParameter("username");
        //将响应信息拼接一下
        resp.setCharacterEncoding("UTF-8");
        PrintWriter out= resp.getWriter();
        out.write("<html lang=\"en\">" +
                "    <head>" +
                "        <meta charset=\"UTF-8\">" +
                "    </head>" +
                "    <body>" +
                "        <form action=\"doTransfer\" method=\"post\">" +
                "            请输入转账账户：<input type=\"text\" name=\"transferName\" value=\"\"><br>" +
                "            请输入转账金额：<input type=\"text\" name=\"transferMoney\" value=\"\"><br>" +
                "            <input type=\"submit\" value=\"确认转账\">" +
                "            <input type=\"hidden\" name=\"username\" value=\""+username+"\">" +
                "        </form>" +
                "    </body>" +
                "</html>");
    }
}

package controller;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
public class WithdrawController extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String username=req.getParameter("username");
        //将响应信息拼接一下
        resp.setCharacterEncoding("UTF-8");
        PrintWriter out= resp.getWriter();
        out.write("<html lang=\"en\">" +
                "    <head>" +
                "        <meta charset=\"UTF-8\">" +
                "    </head>" +
                "    <body>" +
                "        <form action=\"doWithdraw\" method=\"post\">" +
                "            请输入取款金额：<input type=\"text\" name=\"withdrawMoney\" value=\"\"><br>" +
                "            <input type=\"submit\" value=\"确认取款\">" +
                "            <input type=\"hidden\" name=\"username\" value=\""+username+"\">" +
                "        </form>" +
                "    </body>" +
                "</html>");
    }
}

package dao;
import domain.Atm;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public class AtmDao {
    private String url="jdbc:mysql://localhost:3306/atm";
    private String className="com.mysql.jdbc.Driver";
    private String password="cy414ljh212,,,";
    public Atm selectOne(String username){
        Atm atm=null;
        try {
            Class.forName(className);
            Connection connection=DriverManager.getConnection(url,"root",password);
            String sql="SELECT USERNAME,PASSWORD,BALANCE FROM ATM WHERE USERNAME = ?";
            PreparedStatement preparedStatement=connection.prepareStatement(sql);
            preparedStatement.setString(1,username);
            ResultSet resultSet=preparedStatement.executeQuery();
            if(resultSet.next()){
                atm=new Atm();
                atm.setUsername(resultSet.getString("username"));
                atm.setPassword(resultSet.getString("password"));
                atm.setBalance(resultSet.getFloat("balance"));
            }
            resultSet.close();
            preparedStatement.close();
        }catch (Exception e){
            e.printStackTrace();
        }
        return atm;
    }
    public void updateOne(Atm atm){
        try {
            Class.forName(className);
            Connection connection=DriverManager.getConnection(url,"root",password);
            String sql="UPDATE ATM SET PASSWORD = ?,BALANCE = ? WHERE USERNAME = ?";
            PreparedStatement preparedStatement=connection.prepareStatement(sql);
            preparedStatement.setString(1,atm.getPassword());
            preparedStatement.setFloat(2,atm.getBalance());
            preparedStatement.setString(3,atm.getUsername());
            preparedStatement.executeUpdate();
            preparedStatement.close();
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

package domain;
public class Atm {
    private String username;
    private String password;
    private Float balance;
    public Atm(String username, String password, Float balance) {
        this.username = username;
        this.password = password;
        this.balance = balance;
    }
    public Atm() {
    }
    public String getUsername() {
        return username;
    }
    public String getPassword() {
        return password;
    }
    public Float getBalance() {
        return balance;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public void setBalance(Float balance) {
        this.balance = balance;
    }
}

package service;
import dao.AtmDao;
import domain.Atm;
import util.MySpring;
public class AtmService {
    private AtmDao atmDao = MySpring.getJavaBean("dao.AtmDao");
    public String login(String username, String password) {
        String result = "用户名或密码错误";
        Atm atm = atmDao.selectOne(username);
        if (atm != null && atm.getPassword().equals(password)) {
            result = "登陆成功";
        }
        return result;
    }
    public Float inquire(String username) {
        return atmDao.selectOne(username).getBalance();
    }
    public Float dposit(String username, Float dpositMoney) {
        Atm atm = atmDao.selectOne(username);
        atm.setBalance(atm.getBalance() + dpositMoney);
        atmDao.updateOne(atm);
        return atm.getBalance();
    }
    public Float withdraw(String username, Float withdrawMoney) {
        Atm atm = atmDao.selectOne(username);
        if (atm.getBalance() < withdrawMoney) {
            return -1F;
        } else {
            atm.setBalance(atm.getBalance() - withdrawMoney);
            atmDao.updateOne(atm);
            return atm.getBalance();
        }
    }
    public Float transfer(String username, String transferName, Float transferMoney) {
        Atm atm1 = atmDao.selectOne(username);
        Atm atm2 = atmDao.selectOne(transferName);
        if(atm2==null){
            return -1F;
        }else if(atm1.getBalance()<transferMoney){
            return -2F;
        }else{
            atm1.setBalance(atm1.getBalance() - transferMoney);
            atm2.setBalance(atm2.getBalance()+transferMoney);
            atmDao.updateOne(atm1);
            atmDao.updateOne(atm2);
            return atm1.getBalance();
        }
    }
}

package util;

import java.util.HashMap;

public class MySpring {
    private static HashMap<String,Object> beanMap=new HashMap<>();
    public static <T>T getJavaBean(String className){
        T obj=(T) beanMap.get(className);
        if(obj==null){
            try {
                    Class clazz=Class.forName(className);
                    obj=(T) clazz.newInstance();
                    beanMap.put(className,obj);
            }catch (Exception e){
                e.printStackTrace();
            }
        }
        return obj;
    }
}

<?xml version="1.0" encoding="GBK"?>
<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">

<!--    登录-->
    <servlet>
        <servlet-name>login</servlet-name>
        <servlet-class>controller.LoginController</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>login</servlet-name>
        <url-pattern>/login</url-pattern>
    </servlet-mapping>

<!--    查询-->
    <servlet>
        <servlet-name>query</servlet-name>
        <servlet-class>controller.QueryController</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>query</servlet-name>
        <url-pattern>/query</url-pattern>
    </servlet-mapping>

    <!--    存款-->
    <servlet>
        <servlet-name>deposit</servlet-name>
        <servlet-class>controller.DepositController</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>deposit</servlet-name>
        <url-pattern>/deposit</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>doDeposit</servlet-name>
        <servlet-class>controller.DoDepositController</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>doDeposit</servlet-name>
        <url-pattern>/doDeposit</url-pattern>
    </servlet-mapping>

<!--    取款-->
    <servlet>
        <servlet-name>withdraw</servlet-name>
        <servlet-class>controller.WithdrawController</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>withdraw</servlet-name>
        <url-pattern>/withdraw</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>doWithdraw</servlet-name>
        <servlet-class>controller.DoWithdrawController</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>doWithdraw</servlet-name>
        <url-pattern>/doWithdraw</url-pattern>
    </servlet-mapping>

    <!--    转账-->
    <servlet>
        <servlet-name>transfer</servlet-name>
        <servlet-class>controller.TransferController</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>transfer</servlet-name>
        <url-pattern>/transfer</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>doTransfer</servlet-name>
        <servlet-class>controller.DoTransferController</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>doTransfer</servlet-name>
        <url-pattern>/doTransfer</url-pattern>
    </servlet-mapping>

</web-app>

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
    <form action="login" method="post">
        <p>
            账号：<input type="text" name="username" value="请输入用户名" style="color: #999;"
                   onfocus="if(this.value =='请输入用户名'){this.value=''}">
        </p>
        <p>
            密码：<input type="password" name="password">
        </p>
        <input type="submit" value="登录">

    </form>
    </body>
</html>

AtmForServlet.zip