526互联

javaweb--Mapper代理开发

发布时间 2023-11-01 16:54:54作者: na2co3-

 1、使Mapper接口和SQL映射文件放置在同一文件夹下，可以在resources文件夹下新建一个和SQL映射文件相同的文件夹（例如：com/avb/Mapper）不能用.分割文件夹，用/

 2、把SQL映射表里的namespace属性为Mapper接口的全限定名

 3、在Mapper中定义方法，方法名是SQL映射文件中sql语句的id，并保持参数类型和返回值类型一致

List<User> selectAll();

修改resource

 4、编码

import com.avb.Mapper.UserMapper;
import com.avb.pojo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MyBatisDemo {
    public static void main(String[] args) throws IOException {
        //1、加载mybatis的核心配置文件，获取SqlSessionFactory
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //2、获取SqlSession对象，用它来执行sql
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //3、执行sql
       /* List<User> users = sqlSession.selectList("test.selectAll");
        System.out.println(users);*/
        //Class<UserMapper> userMapperClass = UserMapper.class;
        UserMapper usermapper = sqlSession.getMapper(UserMapper.class);
        List<User> users = usermapper.selectAll();
        System.out.println(users);
        //释放资源
        sqlSession.close();
    }
}