主配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/MyBatis?useUnicode=true&characterEncoding=UTF8"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<!-- 加载映射文件 -->
<mappers>
<mapper resource="mapper/usermapper.xml"/>
</mappers>
</configuration>

映射文件

<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- 对sql进行分开处理，隔离 -->
<mapper namespace="com.hl.mybatis.first.mapper.UserMapper">
<!-- 执行数据库的查询 ID用来标识次sql语句，称为Statement的ID
#{}表示一个占位符
parameterType指定输入参数类型
id:接收参数名叫id,如果参数为简单类型，参数名随意
resultType:输出结果的类型,单条记录所映射的对象类。
-->
<select id="findUserById" parameterType="int" resultType="com.hl.myabtis.first.beas.User">
select * FROM user WHERE id = #{id}
</select>
<!--${value}表示sql拼接串 -->
<select id="findUserByNaem" parameterType="String" resultType="com.hl.myabtis.first.beas.User">
select * FROM user WHERE address LIKE '%${value}%'
</select>

<!-- 添加用户
SELECT_LAST_INSERT_ID()只适用于自增长情况
keyProperty:将查询到的结果设置到parameterType指定的属性
order：执行顺序，在插入后执行
resultType：结果类型
-->
<insert id="insertUser" parameterType="com.hl.myabtis.first.beas.User">
<selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
SELECT LAST_INSERT_ID()
</selectKey>
insert into user (username,birthday,sex,address) value(#{username},#{birthday},#{sex},#{address})
</insert>
<!-- 删除
parameterType:参数类型
-->
<delete id="deleteUser" parameterType="java.lang.Integer">
delete from user where id = #{value}
</delete>
<!-- 更新
需求：根据ID更新用户信息
parameterType:需要更新的用户信息
#{id}：从输入的user对象中获取ID属性，名称需要和属性名一致
-->
<update id="updateUserByID" parameterType="com.hl.myabtis.first.beas.User">
update user set username = #{username},birthday = #{birthday},sex = #{sex},address = #{address} where id = #{id}
</update>
</mapper>

mapper接口

package com.hl.mybatis.first.mapper;


import java.util.List;

import com.hl.myabtis.first.beas.User;

public interface UserMapper {

//根据id查询用户信息
public User findUserById(int id) throws Exception;
//添加用户信息
public void insertUser(User user);
//根据id删除用户
public void deleteUser(int id);
//根据用户姓名模糊查找
public List<User> findUserByName(String name);
}

测试：

package com.hl.mybatis.first.test;

import java.io.InputStream;
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.Before;
import org.junit.Test;

import com.hl.myabtis.first.beas.User;
import com.hl.mybatis.first.mapper.UserMapper;

public class UserMapperTest {

private SqlSessionFactory sqlSessionFactory;

@Before
public void before() throws Exception{
//创建sqlSessionFactory
//创建会话工厂
String resource = "SqlMapConfig.xml";
InputStream inputStream = Resources.getResourceAsStream(resource );
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
@Test
public void testInsertUser(){
SqlSession sqlSession = sqlSessionFactory.openSession();
UserMapper usermapper = sqlSession.getMapper(UserMapper.class);
User user = new User();
user.setUsername("卫庄");
user.setAddress("秦时明月之君临天下");
user.setSex('1');
usermapper.insertUser(user);
}
@Test
public void testfindUserByID() throws Exception{
SqlSession sqlSession = sqlSessionFactory.openSession();
UserMapper usermapper = sqlSession.getMapper(UserMapper.class);
User user = usermapper.findUserById(3);
System.out.println(user);
sqlSession.commit();
sqlSession.close();
}
@Test
public void testDeleteUserByID() throws Exception{
SqlSession sqlSession = sqlSessionFactory.openSession();
UserMapper usermapper = sqlSession.getMapper(UserMapper.class);
usermapper.deleteUser(14);
sqlSession.close();
}
@Test
public void testfindUserByName() throws Exception{
SqlSession sqlSession = sqlSessionFactory.openSession();
UserMapper usermapper = sqlSession.getMapper(UserMapper.class);
List<User> userList = usermapper.findUserByName("秦时明月");
sqlSession.close();
for (User user : userList) {
System.out.println(user);
}
}
}

mapper代理开发规范参考​