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04-mybatis注解开发-一对一的注解开发

发布时间：2025-02-03 15:05:47编辑：雪饮阅读（）

拷贝上一个module中的Order.java到D:\os\SpringWebApp\SpringProject2Module9\src\main\java\sp29\domain\Order.java:
package sp29.domain;

import java.util.Date;

public class Order {
    private int id;
    private Date ordertime;
    private double total;
    //当前订单属于哪一个用户
    private User user;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public Date getOrdertime() {
        return ordertime;
    }

    public void setOrdertime(Date ordertime) {
        this.ordertime = ordertime;
    }

    public double getTotal() {
        return total;
    }

    public void setTotal(double total) {
        this.total = total;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    @Override
    public String toString() {
        return "Order{" +
                "id=" + id +
                ", ordertime=" + ordertime +
                ", total=" + total +
                ", user=" + user +
                '}';
    }
}
然后建立一对一映射的接口D:\os\SpringWebApp\SpringProject2Module9\src\main\java\sp29\dao\OrderMapper.java:
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 java.util.List;

public interface OrderMapper {
    @Select(" select *,o.id oid from orders o,user u where o.uid=u.id")
    @Results({
            @Result(column="oid",property = "id"),
            @Result(column="ordertime",property = "ordertime"),
            @Result(column="total",property = "total"),
            @Result(column="uid",property = "user.id"),
            @Result(column="username",property = "user.username"),
            @Result(column="password",property = "user.password")
    })
    public List<Order> findAll();
}
由于之前mybatis配置文件中
<mappers>
    <package name="sp29.dao"/>
</mappers>
该配置是直接扫描sp29.dao这个包的，所以新增的这个接口中的一对一映射的抽象方法也会生效。都在同一个包下。
然后编写测试类及测试方法
D:\os\SpringWebApp\SpringProject2Module9\src\test\java\sp29\MapperTest2.java:
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);
        }
    }
}