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06-mybatis注解开发-一对多的注解开发

发布时间：2025-02-04 09:40:59编辑：雪饮阅读（）

在User.java中新增orders属性并并getter和setter以及重新toString，如：D:\os\SpringWebApp\SpringProject2Module9\src\main\java\sp29\domain\User.java:
package sp29.domain;

import java.util.Date;
import java.util.List;

public class User {

    private int id;
    private String username;
    private String password;
    private Date birthday;
    private List<Order> orders;
    public List<Order> getOrders() {
        return orders;
    }

    public void setOrders(List<Order> orders) {
        this.orders = orders;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }



    public int getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", birthday=" + birthday +
                ", orders=" + orders +
                '}';
    }

}
然后OderMapper.java接口中新增findByUid抽象方法，提供给UserMapper以User为主体查询每个user的订单列表，如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 sp29.domain.User;

import java.util.List;

public interface OrderMapper {

    @Select("select * from orders where uid=#{uid}}")
    public List<Order> findByUid(int uid);

    @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();
}
UserMapper以User为主体查询每个user的订单列表，如D:\os\SpringWebApp\SpringProject2Module9\src\main\java\sp29\dao\UserMapper.java:
package sp29.dao;


import org.apache.ibatis.annotations.*;
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);

    @Select("select * from user")
    @Results({
            @Result(column="id",property = "id"),
            @Result(column = "username",property = "username"),
            @Result(column = "password",property = "password"),
            @Result(
                    property = "orders",
                    column = "id",
                    javaType = List.class,
                    many = @Many(select = "sp29.dao.OrderMapper.findByUid")
            )

    })
    public List<User> findUserAndOrdersAll();
}
然后编写测试类如D:\os\SpringWebApp\SpringProject2Module9\src\test\java\sp29\MapperTest3.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.UserMapper;
import sp29.domain.User;

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

public class MapperTest3 {
    private UserMapper 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(UserMapper.class);
    }
    @Test
    public void testFindAll(){
        List<User> userList=mapper.findUserAndOrdersAll();
        for (User user:userList) {
            System.out.println(user);
        }
    }
}