mybatis学习笔记 2.1 增删改_mybatisp 2.1

（从有道云笔记搬运，博客做备份）

mapper

public interface PlayersDao {
	//查询选手信息列表
	List<Players> getPlayersList();
	
	//查询选手信息，通过id
	Players getPlayersById(String id);
	
	//插入选手信息
	int insertPlayersInfo(Players player);
	
	//更新选手信息，通过id
	int updatePlayersInfoById(Players player);
	
	//删除选手信息，通过id
	int deletePlayersInfoById(String id);
	
}
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XML

<?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">
  
<!-- mapper对应的就是dao，namespace就是对应dao层的地址，绑定接口 -->
<mapper namespace="com.study.mybatis.dao.PlayersDao">
	<!-- id是对应方法的名字，resultType是返回类型 -->
	<select id="getPlayerList" resultType="com.study.mybatis.pojo.Players">
		<!-- 这里面写的是sql -->
		select * from players;
	</select>
	
	<select id="getPlayersById" resultType="com.study.mybatis.pojo.Players" parameterType="java.lang.String">
		select * from players where id = #{id};
	</select>
	
	<insert id="insertPlayersInfo" parameterType="com.study.mybatis.pojo.Players">
		insert into players(id,team,situation) values(#{id}, #{team}, #{situation});
	</insert>
	
	<update id="updatePlayersInfoById" parameterType="com.study.mybatis.pojo.Players">
		update players set team = #{team}, situation = #{situation} where id=#{id};
	</update>
	
	<delete id="deletePlayersInfoById" parameterType="java.lang.String">
		delete from players where id = #{id};
	</delete>
	
</mapper>
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测试类

@Test
public void test() {
    //获取sqlSession
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    //获取mapper（Dao）
    PlayersDao playersDao = sqlSession.getMapper(PlayersDao.class);
    //执行SQL
    /*
    * List<Players> players = playersDao.getPlayersList(); for (Players p :
    * players) { System.out.println(p.getTeam() + "-" + p.getSituation() + "-"
    * +p.getId()); }
    */
    //增删改查
    //这里写mapper，方便理解（现在已经理解了，就不用dao来命名了）
    PlayersDao mapper = playersDao;
    //查
    Players p = mapper.getPlayersById("BurNing");
    System.out.println(p.getTeam() + "-" + p.getSituation());
    //add
    int res = mapper.insertPlayersInfo(new Players("yueru", "DK", "二号位"));
    //成功，res = 1
    if (res > 0) {
        System.out.println("插入成功，提交事务");
        sqlSession.commit();
    }else {
        System.out.println("插入失败，回滚事务");
        sqlSession.rollback();
    }	
    //改
    res = mapper.updatePlayersInfoById(new Players("yueru", "DK", "二号位"));
    //成功，res = 1
    if (res > 0) {
        System.out.println("插入成功，提交事务");
        sqlSession.commit();
    }else {
        System.out.println("插入失败，回滚事务");
        sqlSession.rollback();
    }
    //删
    res = mapper.deletePlayersInfoById("2009");
    if (res > 0) {
        System.out.println("删除成功，提交事务");
        sqlSession.commit();
    }else {
        System.out.println("删除失败，回滚事务");
        sqlSession.rollback();
    }
    //关闭sqlSession
    sqlSession.close();
}
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注意

insert和update没有返回类型
增删改需要提交事务（commit）