mybatis通过注解完成数据库操作（不适用xml配置）

mybatis-config.xml中绑定接口

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

UserMapper.java中写CRUD

package dao;

import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import org.junit.Test;
import pojo.User;

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

public interface UserMapper {
    //需要在核心配置文件绑定
    @Select("select * from user")
    List<User> getUser();

    //方法存在多个参数，所有的参数前面最好加上@Param注解,注解的内容将决定另一个参数
    @Select("select * from user where id = #{id}")
    User getUserById(@Param("id") int id);


}

UserDaoTest中测试

package dao;

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

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


public class UserDaoTest {

    @Test
    public void test()
    {
        SqlSession sqlSession=MybatisUtils.getSqlSession();
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);

        List<User> userList = userMapper.getUser();
        for (User user : userList) {
            System.out.println(user.getName());
        }
        sqlSession.close();
    }
    @Test
    public void testByID()
    {
        SqlSession sqlSession=MybatisUtils.getSqlSession();
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
        User user=userMapper.getUserById(3);
        System.out.println(user.getName());
        sqlSession.close();
    }




}