13-注解增删改查

注解增删改查

自动提交事务

public static SqlSession getSqlSession(){
    return sqlSessionFactory.openSession(true);//自动提交事务
}

编写接口，增加注解

package com.tian.dao;

import com.tian.pojo.User;
import org.apache.ibatis.annotations.*;

import java.util.List;
import java.util.Map;

public interface UserMapper {

    //方法存在多个参数，所有的参数前面必须加上@Param()注解
    @Select("select * from user where id =#{id}")
    User getUserById(@Param("id") int id);

    @Insert("insert into user(id,name,pwd) values(#{id},#{name},#{password})")
    int addUser(User user);

    @Update("update user set name=#{name},pwd=#{password} where id=#{id}")
    int updateUser(User user);

    @Delete("delete from user where id=#{uid}")
    int deleteUser(@Param("uid")int id);
}

测试

import com.tian.dao.UserMapper;
import com.tian.pojo.User;
import com.tian.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.HashMap;
import java.util.List;

public class UserMapperTest {
 
    @Test
    public void test1(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User userById = userMapper.getUserById(1);
        System.out.println(userById);
        //关闭sqlsession
        sqlSession.close();
    }
    @Test
    public void test2(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        int i = userMapper.addUser(new User(6, "he", "456"));
        System.out.println(i);
        sqlSession.close();
    }

    @Test
    public void test3(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
       userMapper.updateUser(new User(6, "hel", "456"));
        sqlSession.close();
    }

    @Test
    public void test4(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        userMapper.deleteUser(6);
        sqlSession.close();
    }
}

• 注意：我们必须要将接口绑定到我们的核心配置文件中！

<!-- 绑定接口   -->
<mappers>
    <mapper class="com.tian.dao.UserMapper"/>
</mappers>

关于@Param()注解

• 基本类型的参数或者String类型，需要加上
• 引用类型不需要加
• 如果只有一个基本类型的话，可以忽略，但是建议大家都加上!·
• 我们在SQL中引用的就是我们这里的@Param()中设定的属性名!