Mybatis注解实现CRUD

我们可以在工具类创建的时候实现自动提交事务！

沿用上一篇博客“Mybatis使用注解开发和执行流程剖析”项目

修改部分工具类代码如下

package com.massimo.dao;

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

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

public interface UserMapper {

    @Select("select * from users")
    List getUsers();

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

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

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

    //删除用户
    @Delete("delete from users where id = #{uid}")
    int deleteUser(@Param("uid") int id);
}

package com.massimo.dao;

import com.massimo.pojo.User;
import com.massimo.utils.MybatisUtils;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.session.SqlSession;
import org.apache.log4j.Logger;
import org.junit.Test;

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


public class UserDaoTest {

    @Test
    public void test(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        //底层主要运用反射
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List userList = mapper.getUsers();
        for(User user : userList){
            System.out.println(user);
        }
        sqlSession.close();
    }

    @Test
    public void getUserById(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = mapper.getUserById(1);
        System.out.println(user);
        sqlSession.close();
    }

    @Test
    public void addUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.addUser(new User(4,"橙留香","234567"));
        sqlSession.close();
    }

    @Test
    public void updateUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.updateUser(new User(4 , "菠萝吹雪" , "345677"));
        sqlSession.close();
    }

    @Test
    public void deleteUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.deleteUser(4);
        sqlSession.close();
    }
}

注意：必须要将接口注册绑定到核心配置文件中！

• 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
• 我们在SQL中引入的就是我们这里的@Param()设定的属性名