jspMVC

package com.xx.control;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class StudentServlet extends HttpServlet {
private static final long serialVersionUID = 1L;// 版本序列---可不要

@Override
public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println();
}
}

=================

package com.xx.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.xx.model.User;
import com.xx.util.JdbcUtil;

public class UserDao {
// 封装数据库对象
private static Connection conn;
private PreparedStatement pstmt;
private ResultSet rs;

// 增
public boolean insert(User entity) {
// 声明返回值变量
boolean flag = false;
// 获取连接对象
conn = JdbcUtil.getConn();
// 定义sql语句
String sql = "insert into users(id,name,pass,sex,age) values(?,?,?,?,?)";
try {
// 根据sql语句创建预处理对象
pstmt = conn.prepareStatement(sql);
// 为占位符赋值
int index = 1;
pstmt.setObject(index++, entity.getId());
pstmt.setObject(index++, entity.getName());
pstmt.setObject(index++, entity.getPass());
pstmt.setObject(index++, entity.getSex());
pstmt.setObject(index++, entity.getAge());
// 执行更新
int i = pstmt.executeUpdate();
if (i > 0) {
flag = true;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

// 释放资源
JdbcUtil.release(rs, pstmt);
return flag;
}

// 删
public boolean deleteById(Integer id) {
// 声明返回值变量
boolean flag = false;
// 获取连接对象
conn = JdbcUtil.getConn();
// 定义sql语句
String sql = "delete from users where id=?";
try {
// 根据sql语句创建预处理对象
pstmt = conn.prepareStatement(sql);
// 为占位符赋值
int index = 1;
pstmt.setObject(index++, id);
// 执行更新
int i = pstmt.executeUpdate();
if (i > 0) {
flag = true;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

// 释放资源
JdbcUtil.release(rs, pstmt);
return flag;
}

// 改
public boolean updateById(User entity) {
// 声明返回值变量
boolean flag = false;
// 获取连接对象
conn = JdbcUtil.getConn();
// 定义sql语句
String sql = "update users set name=?,pass=?,sex=?,age=? where id=?";
try {
// 根据sql语句创建预处理对象
pstmt = conn.prepareStatement(sql);
// 为占位符赋值
int index = 1;
pstmt.setObject(index++, entity.getName());
pstmt.setObject(index++, entity.getPass());
pstmt.setObject(index++, entity.getSex());
pstmt.setObject(index++, entity.getAge());
pstmt.setObject(index++, entity.getId());
// 执行更新
int i = pstmt.executeUpdate();
if (i > 0) {
flag = true;
}
} catch (SQLException e) {
e.printStackTrace();
}

// 释放资源
JdbcUtil.release(rs, pstmt);
return flag;
}

// 查所有
public List<User> findAll() {
List<User> users = new ArrayList<User>();

// 获取连接对象
conn = JdbcUtil.getConn();
// 定义sql语句
String sql = "select * from users";
try {
// 根据sql语句创建预处理对象
pstmt = conn.prepareStatement(sql);
// 执行更新
rs = pstmt.executeQuery();
while (rs.next()) {
// 声明返回值变量
User entity = new User();
entity.setId(rs.getInt("id"));
entity.setName(rs.getString("name"));
entity.setPass(rs.getString("pass"));
entity.setSex(rs.getString("sex"));
entity.setAge(rs.getInt("age"));
users.add(entity);
}

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

// 释放资源
JdbcUtil.release(rs, pstmt);
return users;
}

// 查单个
public User findById(Integer id) {
// 声明返回值变量
User entity = new User();
// 获取连接对象
conn = JdbcUtil.getConn();
// 定义sql语句
String sql = "select * from users where id=?";
try {
// 根据sql语句创建预处理对象
pstmt = conn.prepareStatement(sql);
// 为占位符赋值
int index = 1;
pstmt.setObject(index++, id);
// 执行更新
rs = pstmt.executeQuery();
if (rs.next()) {
entity.setId(rs.getInt("id"));
entity.setName(rs.getString("name"));
entity.setPass(rs.getString("pass"));
entity.setSex(rs.getString("sex"));
entity.setAge(rs.getInt("age"));
}

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

// 释放资源
JdbcUtil.release(rs, pstmt);
return entity;
}
}

====================

package com.xx.model;

public class User {
private Integer id;
private String name;
private String pass;
private String sex;
private Integer age;

===============

package com.xx.Test;

import org.junit.Test;

import com.xx.dao.UserDao;
import com.xx.model.User;

public class UserTest {
UserDao uDao = new UserDao();

@Test
public void insert() {
User entity = new User();
entity.setName("测试1");
entity.setPass("123");
entity.setSex("女");
entity.setAge(21);
boolean flag = uDao.insert(entity);
if (flag) {
System.out.println("插入成功");
} else {
System.out.println("插入失败");
}
}

@Test
public void findById() {
User entity = uDao.findById(1);
System.out.println(entity.toString());
}

@Test
public void update() {
User entity = uDao.findById(4);
entity.setName("测试2");
entity.setAge(20);
boolean flag = uDao.updateById(entity);
if (flag) {
System.out.println("更新成功");
} else {
System.out.println("更新失败");
}
}

@Test
public void deleteById() {
boolean flag = uDao.deleteById(27);
if (flag) {
System.out.println("删除成功");
} else {
System.out.println("删除失败");
}
}
}

=============

package com.xx.util;

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

public class JdbcUtil {
public static Connection getConn() {
// 传统jdbc取得数据库连接
Connection con = null;
String driver = "org.gjt.mm.mysql.Driver";
String db_server = "jdbc:mysql://127.0.0.1/jspdemo"; // jspdemo表示database
String user = "root";
String pwd = "123";// 设置你的数据库密码
try {
// 加载数据库驱动
Class.forName(driver);
// 创建连接
con = DriverManager.getConnection(db_server, user, pwd);
} catch (Exception e) {
e.printStackTrace();
}
// 返回一个数据库连接
return con;
}

// 释放资源方法
public static void release(ResultSet rs, PreparedStatement pstmt) {
// 关闭顺序由里到外（使用的时候首先打开的事pstmt→rs，关闭的时候反过来）

if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (pstmt != null) {
try {
pstmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}

============

create database jspdemo;
use jspdemo;
CREATE TABLE user (
id int unsigned not null auto_increment primary key,
name varchar(20) DEFAULT NULL,
password varchar(20) DEFAULT NULL,
sex varchar(10) DEFAULT NULL,
age int DEFAULT NULL
);
charset gbk;