在上篇mybatis小程式的基礎上,實作增删改查
1、UserMapper接口
package com.lizheng.dao;
import com.lizheng.pojo.User;
import java.util.List;
/**
* 操作對象資料庫的實體
*/
public interface UserMapper {
//隻寫方法名,不寫方法體,花括号也不行
//查詢所有使用者
List<User> getUserList();
//根據id查詢使用者
User getUserById (int id);
//增加使用者
int addUser (User user);
//修改使用者
int modifyUser (User user);
//根據使用者id删除使用者
int deleteUserById (int id);
}
2、UserMapper.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">
<!--namespace對應全路徑下的mapper-->
<mapper namespace="com.lizheng.dao.UserMapper">
<!-- id 對應 重寫方法名稱-->
<!-- resultType 對應傳回類型,list 隻寫範型-->
<select id="getUserList" resultType="com.lizheng.pojo.User">
select * from mybatis.user
</select>
<select id="getUserById" parameterType="int" resultType="com.lizheng.pojo.User">
select * from mybatis.user where id = #{id}
</select>
<!-- 對象中的屬性可以直接取出來-->
<insert id="addUser" parameterType="com.lizheng.pojo.User">
insert into mybatis.user (id,name,pwd) values (#{id},#{name},#{pwd})
</insert>
<update id="modifyUser" parameterType="com.lizheng.pojo.User">
update mybatis.user set name=#{name},pwd=#{pwd} where id = #{id} ;
</update>
<delete id="deleteUserById" parameterType="int" >
delete from mybatis.user where id = #{id}
</delete>
</mapper>
3、測試類
package com.lizheng.dao;
import com.lizheng.Utils.MybatisUtils;
import com.lizheng.pojo.User;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.List;
//測試
public class UserMapperTest {
@Test
public void test(){
//第一步:擷取sqlsession對象
SqlSession session = MybatisUtils.getSqlSession();
//執行SQL語句
UserMapper mapper = session.getMapper(UserMapper.class);
List<User> userList = mapper.getUserList();
for (User user : userList) {
System.out.println(user);
}
//關閉sqlSession
session.close();
}
@Test
public void getUserByIdTest (){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
User user = mapper.getUserById(3);
System.out.println(user);
sqlSession.close();
}
@Test
public void addUserTest(){
//增删改一定要送出事務
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
int junjun = mapper.addUser(new User(1, "junjun", "123456"));
if (junjun > 0 ){
System.out.println(junjun+"增加成功");
}
//送出事務
sqlSession.commit();
//關閉sqlsession對象
sqlSession.close();
}
@Test
public void modifyUserTset(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
int doudou = mapper.modifyUser(new User(1, "doudou", "123456"));
if (doudou > 0) {
System.out.println("修改成功");
}
sqlSession.commit();
sqlSession.close();
}
@Test
public void deleteUserByIdTest (){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
int i = mapper.deleteUserById(1);
if (i>0) {
System.out.println("删除成功");
}
sqlSession.commit();
sqlSession.close();
}
}
注意:1、增删改查sql語句的寫法,多練
2、增删改需要送出事務,sqlSession.commit()