目的： 使用Mybatis完成增删改查功能。

第一步，配置好mybatis的环境，参考博客：

https://blog.csdn.net/tomwildboar/article/details/81329060

第二步：pojo，和sqlMapConfig.xml主配置文件和上面博客中一样，就不写了。直接给出test和User.xml文件

User.xml配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!-- 写sql语句的 
	namespace 命名空间，这个mapper的名字
-->
<mapper namespace="test">
	<!-- 
		通过id查询一个用户
		id:是待会我们调用那条sql的标识
		parameterType:传入的参数的类型 （支持基本数据类型简写）
		resultType:返回的数据类型
		#{xxx} : 相当于占位符 xxx随便写
	 -->
	
	<select id="findUserById" parameterType="Integer" resultType="com.ziyang.mybatis.pojo.User">
		select * from user where id = #{a}
	</select>
	<!-- 
		根据用户名模糊查询
		#{}  :  相对于占位符 id = #{v}  ==  id = '1'
		${}  :  相当于字符串拼接  id = ${value}  == 	id = 1
		#{} 里面可以随意写  ${} 里面只能是value
	
	-->
	<select id="findUserByUsername" parameterType="String" resultType="com.ziyang.mybatis.pojo.User">
		<!--  	select * from user where username like '%${value}%'-->
		select * from user where username like "%"#{value}"%"
	
	</select> 
	
	<!-- 添加用户 -->
	<insert id="insertUser" parameterType="com.ziyang.mybatis.pojo.User">
		<!-- 获取这个条数据的id -->
		<selectKey keyProperty="id" resultType="Integer" order="AFTER">
			select LAST_INSERT_ID()
		</selectKey>
		insert into user (username,birthday,sex,address) 
		values (#{username},#{birthday},#{sex},#{address}) 
	</insert>
	
	<!-- 更新用户 -->
	<update id="updateUserById" parameterType="com.ziyang.mybatis.pojo.User">
		update user
		set username = #{username},sex = #{sex},
			birthday = #{birthday},address = #{address}
		where id = #{id}
	
	</update>
	
	<!-- 删除 -->
	<delete id="deleteById" parameterType="Integer">
		delete from user 
		where id = #{v} 
	</delete>	
	
	
</mapper>

test测试类

package com.ziyang.mybatis.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import com.ziyang.mybatis.pojo.User;

public class Demo_1 {
	
	/*根据id查询*/
//	@Test
//	public void test1() throws IOException {
//		//加载核心配置文件
//		InputStream stream = Resources.getResourceAsStream("sqlMapConfig.xml");
//		//创建一个sqlSessionFactory
//		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(stream);
//		//创建sqlsession
//		SqlSession sqlSession = sqlSessionFactory.openSession();
//		//执行sql语句
//		User user = sqlSession.selectOne("test.findUserById",1);
//		
//		System.out.println(user);
//	}
	
	/*根据name模糊查询*/
	@Test
	public void test2() throws IOException {
		//加载核心配置文件
		InputStream stream = Resources.getResourceAsStream("sqlMapConfig.xml");
		//创建一个sqlSessionFactory
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(stream);
		//创建sqlsession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		//执行sql语句
		List<User> user = sqlSession.selectList("test.findUserByUsername","五");
		for (User user2 : user) {
			System.out.println(user2);
		}
		
	}
	/*添加用户*/
	@Test
	public void test3() throws IOException {
		//加载核心配置文件
		InputStream stream = Resources.getResourceAsStream("sqlMapConfig.xml");
		//创建一个sqlSessionFactory
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(stream);
		//创建sqlsession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		//执行sql语句
		User user = new User();
		user.setUsername("aa");
		user.setBirthday(new Date());
		user.setAddress("aaa");
		user.setSex("a");
		int i = sqlSession.insert("test.insertUser",user);
		sqlSession.commit();
		System.out.println(user.getId());
		
	}
	
	/*添加用户*/
	@Test
	public void test4() throws IOException {
		//加载核心配置文件
		InputStream stream = Resources.getResourceAsStream("sqlMapConfig.xml");
		//创建一个sqlSessionFactory
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(stream);
		//创建sqlsession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		//执行sql语句
		User user = new User();
		user.setId(27);
		user.setUsername("bb");
		user.setBirthday(new Date());
		user.setAddress("bb");
		user.setSex("b");
		int i = sqlSession.update("test.updateUserById", user);
		sqlSession.commit();
		
	}
	
	//删除	
	@Test
	public void test5() throws IOException {
		//加载核心配置文件
		InputStream stream = Resources.getResourceAsStream("sqlMapConfig.xml");
		//创建一个sqlSessionFactory
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(stream);
		//创建sqlsession
		SqlSession sqlSession = sqlSessionFactory.openSession();
		//执行sql语句
		
		int i = sqlSession.delete("test.deleteById", 27);
		sqlSession.commit();
		
	}
	
	
	
}