一、实体类实现增删改查
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1.1、增 > insert
①抽象接口
Integer addUserInfo(User user);
②xml
- 这里要注意关键字的书写方式
- like要用括号来包起来，防止跟关键字引起冲突！
<insert id="addUserInfo" parameterType="com.dbright.pojo.User">
insert into user(name,age,`like`)values(#{name},#{age},#{like} )
</insert>
③测试类
- session.commit(); 这个是提交事务！必须得写，不然语句不会生效！
@Test
public void addUserInfo() {
SqlSession session = MybatisUtils.getSession();
UserMapper mapper = session.getMapper(UserMapper.class);
//造数据
User user = new User();
user.setName("面条");
user.setAge(22);
user.setLike("王者荣耀");
Integer statusNum = mapper.addUserInfo(user);
System.out.println(statusNum);
session.commit();//提交事务
session.close();
}
④执行结果
image.png
image.png
1.2、删 > delete
①抽象接口
Integer deleteUserInfo(int id);
②xml
<delete id="deleteUserInfo" parameterType="int">
delete from user where id = #{id}
</delete>
③测试类
- 删除也需要提交事务才会生效！
@Test
public void deleteUserInfo() {
SqlSession session = MybatisUtils.getSession();
UserMapper mapper = session.getMapper(UserMapper.class);
Integer statusNum = mapper.deleteUserInfo(26);
System.out.println(statusNum);
session.commit();//提交事务
session.close();
}
④执行结果
image.png
1.3、改 > update
①抽象接口
Integer updateUserInfo(User user);
②xml
<update id="updateUserInfo" parameterType="com.dbright.pojo.User">
update user set name = #{name},age = #{age},`like` = #{like} where id = #{id}
</update>
③测试类
@Test
public void updateUserInfo() {
SqlSession session = MybatisUtils.getSession();
UserMapper mapper = session.getMapper(UserMapper.class);
//造数据
User user = new User();
user.setId(30);
user.setName("丁大大");
user.setAge(23);
user.setLike("钓鱼");
Integer statusNum = mapper.updateUserInfo(user);
System.out.println(statusNum);
session.commit();//提交事务
session.close();
}
④执行结果
- 原先：
image.png
- 执行后：
image.png
1.4、查 > select
①抽象接口
List<User> getUserInfo();
User getUserInfoById(int id);
User getUserInfoByIF(@Param("name") String name , @Param("age") Integer age);
②xml
<select id="getUserInfo" resultType="com.dbright.pojo.User">
select * from user
</select>
<select id="getUserInfoById" resultType="com.dbright.pojo.User">
select
*
from
user
where
id = #{id}
</select>
<select id="getUserInfoByIF" resultType="com.dbright.pojo.User">
select
*
from
`user`
where
`name` = #{name}
and
age = #{age}
</select>
③测试类
@Test
public void selectUser() {
SqlSession session = MybatisUtils.getSession();
UserMapper mapper = session.getMapper(UserMapper.class);
List<User> users = mapper.getUserInfo();
for (User map: users){
System.out.println(map);
}
session.close();
}
@Test
public void getUserInfoById() {
SqlSession session = MybatisUtils.getSession();
UserMapper mapper = session.getMapper(UserMapper.class);
User userInfo = mapper.getUserInfoById(30);
System.out.println(userInfo);
session.close();
}
@Test
public void getUserInfoByIF() {
SqlSession session = MybatisUtils.getSession();
UserMapper mapper = session.getMapper(UserMapper.class);
User userInfo = mapper.getUserInfoByIF("丁大大",23);
System.out.println(userInfo);
session.close();
}
④执行结果
- 数据如下：
image.png
- 查询表里所有信息
image.png
- 待条件查询
image.png
- 多条件查询
image.png
二、Map实现增删改查
- 这里不举太多例子了，因为mapper会自动将map中的值根据key对应起来
- 十分方便，在实际工作中，使用Map查询居多
- 前提是前后端联调使用的是PostMan或者Yapi等联调工具
- 如果使用swaager联调，必须使用实体类来进行开发
- 例子：
①接口类
Integer addUserInfo(Map<String,Object> map);
②xml
<insert id="addUserInfo" parameterType="map">
insert into user(name,age,`like`)values(#{name},#{age},#{like} )
</insert>
③测试类
@Test
public void addUserInfo() {
SqlSession session = MybatisUtils.getSession();
UserMapper mapper = session.getMapper(UserMapper.class);
//造数据
Map<String,Object> map = new HashMap<>();
map.put("name","面条");
map.put("age","50");
map.put("like","王者荣耀");
Integer statusNum = mapper.addUserInfo(map);
System.out.println(statusNum);
session.commit();//提交事务
session.close();
}
④执行结果
image.png
作者：大鱼丶
原文链接：https://juejin.cn/post/6982743087143452708
