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05-mybatis注解开发-一对一的注解开发2

发布时间：2025-02-03 17:25:14编辑：雪饮阅读（）

上篇的一对一的注解方式mybatis开发实际上还欠优雅。
由于D:\os\SpringWebApp\SpringProject2Module9\src\main\java\sp29\dao\UserMapper.java中有findById的抽象方法，如：
package sp29.dao;


import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import sp29.domain.User;

import java.util.List;

public interface UserMapper {
    @Select("select * from user")
    public List<User> findAll();

    @Select("select * from user where id=#{id}")
    public User findById(int id);

    @Delete("delete from user where id=#{id}")
    public void delete(int id);

    @Update("update user set username=#{username},password=#{password} where id=#{id}")
    public void update(User user);

    @Insert("insert into user values(#{id},#{username},#{password},'','',#{birthday})")
    public void save(User user);
}
所以D:\os\SpringWebApp\SpringProject2Module9\src\main\java\sp29\dao\OrderMapper.java中可以利用该findById方法，如：
package sp29.dao;

import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import sp29.domain.Order;
import sp29.domain.User;

import java.util.List;

public interface OrderMapper {
    @Select(" select * from orders")
    @Results({
            @Result(column="id",property = "id"),
            @Result(column="ordertime",property = "ordertime"),
            @Result(column="total",property = "total"),
            @Result(
                    property = "user",
                    column = "uid",
                    javaType = User.class,
                    one = @org.apache.ibatis.annotations.One(
                            select = "sp29.dao.UserMapper.findById"
                    )
            )
    })
    public List<Order> findAll();
}
这样同样实现了一对一的注解开发，并且看起来更加优雅。
测试代码D:\os\SpringWebApp\SpringProject2Module9\src\test\java\sp29\MapperTest2.java保持不变：
package sp29;

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 org.junit.Before;
import org.junit.Test;
import sp29.dao.OrderMapper;
import sp29.domain.Order;

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

public class MapperTest2 {
    private OrderMapper mapper;
    @Before
    public void before() throws IOException{
        InputStream resourceAsStream= Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession=sqlSessionFactory.openSession(true);
         mapper=sqlSession.getMapper(OrderMapper.class);
    }
    @Test
    public void testFindAll(){
        List<Order> orderList=mapper.findAll();
        for (Order order:orderList) {
            System.out.println(order);
        }
    }
}