05-MyBatis_关联映射之一对多

朴灿烈づ我的快乐病毒、 2022-09-17 12:22 74阅读 0赞

一对多: 一个人 对应 多个订单

# 0. 源码下载 #

[MyBatis\_关系映射之一对多-src.zip][MyBatis_-src.zip]

# 1. 表 #

##  1.1 表名和字段 ##

person(personId,personName,personAddress,personTel)  
orders(orderId,ordreNumber,orderPrice,pid)

##  1.2 SQL脚本 ##

USE mybatis;
    
    CREATE TABLE person
    (
      personId VARCHAR(36) PRIMARY KEY,
      personName VARCHAR(64),
      personAddress VARCHAR(128),
      personTel VARCHAR(11)
    );
    
    -- order 在MySQL中是关键字
    CREATE TABLE orders
    (
      orderId VARCHAR(36) PRIMARY KEY,
      orderNumber VARCHAR(20),
      orderPrice INT,
      pid VARCHAR(36)
    );
    
    INSERT INTO person VALUES('001', 'Jack', 'Wuhan', '1234567');
    
    INSERT INTO orders VALUES('O_00001', '00001', 100, '001');
    INSERT INTO orders VALUES('O_00002', '00002', 200, '001');
    
    SELECT p.*, o.*
    FROM person p 
      JOIN orders o ON (p.personId=o.pid)
    WHERE p.personId = '001'

# 2. 实体 #

public class Person {
    
        private String id;
        private String name;
        private String address;
        private String tel;
        
        List<Order> orders;
    
        // get / set 已省略
    }    
    
    public class Order {
        
        private String id;
        private String number;
        private Integer price;
    
        // get / set 已省略
    }

# 3. 总配置  #

# 4. 映射文件 #

<mapper namespace="com.hehe.mybatis.domain.Person">
    
    	<resultMap type="Person" id="personMap">
    		<id column="personId" property="id"/>
    		<result column="personName" property="name"/>
    		<result column="personAddress" property="address"/>
    		<result column="personTel" property="tel"/>
    		
    		
    		
    		<collection property="orders" ofType="Order">
    			<id column="orderId" property="id"/>
    			<result column="orderNumber" property="number"/>
    			<result column="orderPrice" property="price"/>
    		</collection>
    		
    	</resultMap>
    	
    	<select id="selectPersonById" parameterType="string" resultMap="personMap">
    		SELECT p.*, o.*
    		FROM person p 
    		  JOIN orders o ON (p.personId=o.pid)
    		WHERE p.personId = #{id}
    	</select>
    
    </mapper>

# 5. 测试 #

/*
    <select id="selectPersonById" parameterType="string" resultMap="orderMap">
    	SELECT p.*, o.* 
    	FROM person p 
      		JOIN orders o ON (p.personId=o.pid);
    	where p.id = #{id}
    </select> 
    */	@Test public void testSelectPersonById() throws Exception {
    		SqlSession session = sqlSessionFactory.openSession();
    		
    		List<Person> persons = session.selectList("com.hehe.mybatis.domain.Person.selectPersonById", "001");
    		
    		// 在此处打断点查看
    		for (Person p : persons) {
    			System.out.println(
    					p.getId() + "\t" +
    					p.getName() + "\t" +
    					p.getAddress() + "\t" +
    					p.getTel() 
    					);
    			for (Order o : p.getOrders()) {
    				System.out.println(
    						o.getId() + "\t" +
    						o.getNumber() + "\t" +
    						o.getPrice() 
    						);
    			}
    		}
    		
    		session.close();
    	}

[MyBatis_-src.zip]: http://download.csdn.net/detail/wuqinfei_cs/6424563