06-MyBatis_关联映射之多对一

向右看齐 2022-09-17 12:23 129阅读 0赞

# 0. 源码下载 #

[MyBatis\_关联映射之多对一\_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(MySQL) ##

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'
    
    SELECT o.*, p.*
    FROM orders o 
      JOIN person p ON (p.personId=o.pid)
    WHERE o.orderId = 'O_00001'

# 2. 实体 #

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

# 3. 总配置  #

同上一篇[05-MyBatis\_关联映射之一对多][05-MyBatis]

# 4. 映射文件 #

<mapper namespace="com.hehe.mybatis.domain.Order">
        <resultMap type="Order" id="orderMap">
            <id column="orderId" property="id"/>
            <result column="orderNumber" property="number"/>
            <result column="orderPrice" property="price"/>
            
            
            
            <association property="person" javaType="Person">
                <id column="personId" property="id"/>
                <result column="personName" property="name"/>
                <result column="personAddress" property="address"/>
                <result column="personTel" property="tel"/>
            </association>
        </resultMap>
        
        
        <select id="selectOrderById" parameterType="string" resultMap="orderMap">
            SELECT o.*, p.*
            FROM orders o 
              JOIN person p ON (p.personId=o.pid)
            WHERE o.orderId = 'O_00001' 
        </select>
        
    </mapper>

# 5. 测试 #

/* 
    
    <select id="selectOrderById" parameterType="string" resultMap="orderMap">
    	SELECT o.*, p.*
    	FROM orders o 
    	  JOIN person p ON (p.personId=o.pid)
    	WHERE o.orderId = 'O_00001'	
    </select>
    */	@Test public void testSelectOrderById() throws Exception {
    		SqlSession session = sqlSessionFactory.openSession();
    		
    		Order order = session.selectOne("com.hehe.mybatis.domain.Order.selectOrderById", "O_00001");
    		System.out.println(
    						order.getId() + "\t" +
    						order.getNumber() + "\t" +
    						order.getPrice() + "\t" +
    						order.getPerson().getId() + "\t" +
    						order.getPerson().getName() + "\t" +
    						order.getPerson().getAddress() + "\t" +
    						order.getPerson().getTel()
    				);		
    		session.close();
    	}

[MyBatis_src.zip]: http://download.csdn.net/detail/wuqinfei_cs/6424757
[05-MyBatis]: http://blog.csdn.net/wuqinfei_cs/article/details/12875909