爱心捐款系统(MVC+MySQL)+前后端分离

具备的测试工具：Eclipse，MySQL数据库，HBuilder，jstl1.2jar，mysql.connector.java.8.0.jar包

jstl1.2jar下载地址：https://pan.baidu.com/s/1T23zxoEg3jlZHFikrbWtHw

mysql.connector.java.8.0.jar包下载地址：https://pan.baidu.com/s/1kqfOuxo3nOT--CTrlp1BmA

首先打开Eclipse创建一个动态Web项目(Dynamic Web Project)，在Src下分别创建以下包

其中web其实就是对应action层，这就是典型的MVC模型，这是属于后端

首先创建与你数据库的表结构对应的实体类

1、我的数据库结构如下

建立数据库
create database LoveDB;

建立数据表LoveInHeart
use LoveDB;
create table LoveInHeart(
lid int auto_increment primary key,
lname varchar(50) not null,
lsex varchar(50) not null,
ltime date not null,
lmoney float
);

然后可以向里面添加一些测试数据

insert into LoveInHeart(lname,lsex,ltime,lmoney)
values ('廖远平','男','1999-02-15',1000000);

insert into LoveInHeart(lname,lsex,ltime,lmoney)
values ('彭桂妮','女','1998-8-19',1000);

insert into LoveInHeart(lname,lsex,ltime,lmoney)
values ('科比','男','2008-05-05',100);

然后实体类的属性参数要和数据库的表结构保持一致，注：实体类是放在entity包下

 声明变量以后进行封装，右键选择 source --> Getter and Setter ，然后select All 点击完成

 接下来创建与数据库链接的DatabaseConnection类来完成与数据库的交互，在dao包下新建一个类，名字为：BaseDB

package com.nf.dao;

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

public class BaseDao {

    private static final String DRIVER_CLASS = "com.mysql.cj.jdbc.Driver";
    private static final String SERVER_IP = "localhost";// 服务器IP地址
    private static final String DATABASE_NAME = "lovedb";// 连接到哪一个数据库
    private static final String USER_NAME = "root";// 用户名
    private static final String PASSWORD = "123456";// 密码

    public Connection getConnection() {
        Connection conn = null;
        String jdbcUrl = "jdbc:mysql://" + SERVER_IP + ":3306/" + DATABASE_NAME
                + "?serverTimezone=Asia/Shanghai&useSSL=true";
        try {
            Class.forName(DRIVER_CLASS);
            conn = DriverManager.getConnection(jdbcUrl, USER_NAME, PASSWORD);
        } catch (Exception e) {
            System.out.println("获取连接时，异常" + e.getMessage());
            conn = null;
        }
        return conn;
    }

    public void closeAll(Connection conn, PreparedStatement pst, ResultSet rs) {

        try {
            if (rs != null) {
                rs.close();
            }
            if (pst != null) {
                pst.close();
            }
            if (conn != null) {
                conn.close();
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

在dao层下面创建一个Interface类，声明三个方法(查询、添加、删除)，名字：LoveInHeartDao

package com.nf.dao;

import java.util.List;
import com.nf.entity.LoveInHeart;
import com.nf.util.MyPage;

public interface LoveInHeartDao{
    
    public List<LoveInHeart> getAll(MyPage myPage);
    public boolean add(LoveInHeart love);
    public boolean delete(int id);
    
}

然后创建一个实现接口class类(Implments)，名字：LoveInHeart_Impl

package com.nf.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.nf.entity.LoveInHeart;
import com.nf.util.MyPage;

public class LoveInHeartDaoImpl extends BaseDao implements LoveInHeartDao {

    @Override  //查询
    public List<LoveInHeart> getAll(MyPage myPage) {
        // 操作数据库，需要一个连接Connection
        Connection connection = getConnection();
        PreparedStatement prepareStatement = null;
        ResultSet resultSet = null;
        List<LoveInHeart> loveInHeartList = new ArrayList();
             
        String sql_data = "select * from loveinheart order by lid desc ";
        String sql_recodeCount = "select count(1) as mycount from loveinheart";
        
        sql_data += "limit ";
        sql_data += (myPage.getCurrentPage()-1)*myPage.getPerPageSize();
        sql_data += ",";
        sql_data += myPage.getPerPageSize();
        
        System.out.println("分页的SQL:"+sql_data);
        
        try {
            
            prepareStatement = connection.prepareStatement(sql_data);
            resultSet = prepareStatement.executeQuery();
            while (resultSet.next()) {
                LoveInHeart l = new LoveInHeart();
                l.setLid(resultSet.getInt("lid"));
                l.setLname(resultSet.getString("lname"));
                l.setLsex(resultSet.getString("lsex"));
                l.setLtime(resultSet.getDate("ltime"));
                l.setLmoney(resultSet.getFloat("lmoney"));
                loveInHeartList.add(l);
            }

        } catch (SQLException e) {

            e.printStackTrace();
        }
        
        try {
            prepareStatement = connection.prepareStatement(sql_recodeCount);
            resultSet = prepareStatement.executeQuery();
            resultSet.next();
            myPage.setRecodeCount( resultSet.getInt("mycount") );
        } catch (SQLException e) {
            
            e.printStackTrace();
        }
        
        
        closeAll(connection, prepareStatement, resultSet);

        // System.out.println(connection);
        return loveInHeartList;
    }

    @Override   //添加
    public boolean add(LoveInHeart love) {
        // 操作数据库，需要一个连接Connection
        Connection connection = getConnection();
        PreparedStatement prepareStatement = null;
        try {
            prepareStatement = connection
                    .prepareStatement("insert into LoveInHeart(lname,lsex,ltime,lmoney) values (?,?,?,?)");
            prepareStatement.setString(1, love.getLname());
            prepareStatement.setString(2, love.getLsex());
            prepareStatement.setDate(3, love.getLtime());
            prepareStatement.setFloat(4, love.getLmoney());
            prepareStatement.executeUpdate();

            closeAll(connection, prepareStatement, null);
            return true;

        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }

    }

    @Override    //删除
    public boolean delete(int id) {
        // 操作数据库，需要一个连接Connection
        Connection connection = getConnection();
        PreparedStatement prepareStatement = null;
        try {
            prepareStatement = connection
                    .prepareStatement("delete from LoveInHeart where lid=?");
            prepareStatement.setInt(1, id);
            prepareStatement.executeUpdate();

            closeAll(connection, prepareStatement, null);
            return true;

        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }

}

接下来在Service层再创建一个interface类，名字：LoveInHeartService

package com.nf.service;

import java.util.List;

import com.nf.entity.LoveInHeart;
import com.nf.entity.MyData;

public interface LoveInHeartService {
    public MyData getAll(int currentPage);
    public boolean add(LoveInHeart love);
    public boolean delete(int id);
}

随机在同Service层下实现该接口