Mybatis resultMap实现一对多的映射

淩亂°似流年 2022-03-02 15:08 372阅读 0赞

假设user和orders为一对多的关系，一个user对应多个订单  
User.java

package per.czt.ssm.domain;
    
    import java.util.List;
    import java.util.Set;
    
    public class User {
    	private Integer id;
    	private String username;
    	
    	private String password;
    
    	private List<Orders> ordersList;
    	public Integer getId() {
    		return id;
    	}
    	public void setId(Integer 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;
    	}
    	public List<Orders> getOrdersList() {
    		return ordersList;
    	}
    	public void setOrdersList(List<Orders> ordersList) {
    		this.ordersList = ordersList;
    	}
    	
    	
    	
    	
    	
    }

Orders.java

package per.czt.ssm.domain;
    
    public class Orders {
    	private Integer id;
    	private User user;
    	private Integer userId;
    	
    	public Integer getId() {
    		return id;
    	}
    	public void setId(Integer id) {
    		this.id = id;
    	}
    	public User getUser() {
    		return user;
    	}
    	public void setUser(User user) {
    		this.user = user;
    	}
    	public Integer getUserId() {
    		return userId;
    	}
    	public void setUserId(Integer userId) {
    		this.userId = userId;
    	}
    	
    	
    }

配置文件

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    
    
    <mapper namespace="per.czt.ssm.domain">
    	
        <resultMap type="per.czt.ssm.domain.Orders" id="Orders">
    		<id property="id" column="oid" />
    		
    		<association property="user"
    			javaType="per.czt.ssm.domain.User" >
    			
    			<id property="id" column="uid" />
    		  <result property="username" column="username" />
    			<result property="password" column="password" />
    
    		</association>
    	</resultMap>
    
    	
    
    	
    	<select id="searchOrders"
    		parameterType="per.czt.ssm.domain.Orders" resultMap="Orders">
    		select * from
    		orders,user where user.uid=orders.userId
    
    	</select>
    
    	
    	<resultMap type="per.czt.ssm.domain.User" id="userMap">
    		<id property="id" column="uid" />
    		<result column="username" property="username" />
    		<result column="password" property="password" />
    		<collection property="ordersList"
    			ofType="per.czt.ssm.domain.Orders" >
    			<id property="id" column="oid" />
    			<result property="userId" column="userId"/>
    		
    		</collection>
    	</resultMap>
    
    	
    	<select id="searchUser" parameterType="per.czt.ssm.domain.User"
    		resultMap="userMap">
    		select *  from user,orders where user.uid=orders.userId
    
    	</select>
    
    
    
    
    
    
    
    
    
    
    </mapper>