MyBatis注解之多对一

1、CategoryMapper（一方）

public interface CategoryMapper {@Select(" select * from category_ where id = #{id}")public Category get(int id);
}

2、ProductMapper（多方）

public interface ProductMapper {@Select(" select * from product_ ")@Results({ @Result(property="category",column="cid",one=@One(select="com.how2java.mapper.CategoryMapper.get")) })public List<Product> list();
}

3、mybatis-config.xml

<mappers><mapper class="com.how2java.mapper.CategoryMapper"/> <mapper class="com.how2java.mapper.ProductMapper"/> </mappers>

4、Test类

public class TestMybatis {public static void main(String[] args) throws IOException {String resource = "mybatis-config.xml";InputStream inputStream = Resources.getResourceAsStream(resource);SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);SqlSession session = sqlSessionFactory.openSession();ProductMapper mapper = session.getMapper(ProductMapper.class);List<Product> ps= mapper.list();for (Product p : ps) {System.out.println(p + "\t对应的分类是:\t" + p.getCategory().getName());}session.commit();session.close();}
}

运行结果：