一. 简介:
本实例使用顾客和订单的例子做说明: 一个顾客可以有多个订单, 一个订单只对应一个顾客
二. 例子:
1. 代码结构图:
2. 建表语句:
CREATE DATABASE test;
USE test;
CREATE TABLE person(
personId VARCHAR(36) PRIMARY KEY,
personName VARCHAR(64),
personAddress VARCHAR(128),
personTel VARCHAR(11)
);
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'
/**
* 客户实体
*/
public class Person {
private String id;
private String name;
private String address;
private String tel;
private List orders;
@Override
public String toString() {
return "{id: " + id + ", name: " + name + ", address: " + address + ", tel: " + tel + "}";
}
}
// 省略getter和setter方法
/**
* 订单实体
*/
public class Order {
private String id;
private String number;
private int price;
private Person person;
@Override
public String toString() {
return "{id: " + id + ", number: " + number + ", price: " + price + "}";
}
}
// 省略getter和setter方法
/**
* 测试一对多和多对一
*/
public class MybatisTest {
private SqlSessionFactory ssf;
@Before
public void initSF() throws Exception {
String resource = "sqlMapConfig.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
ssf = new SqlSessionFactoryBuilder().build(inputStream);
}
@Test//一对多关联查询
public void selectPersonById()throws Exception{
SqlSession session = ssf.openSession();
Person person = session.selectOne("com.zdp.domain.Person.selectPersonById", "001");
System.out.println(person.getOrders());
}
@Test//多对一关联查询
public void selectOrderById()throws Exception{
SqlSession session = ssf.openSession();
Order order = session.selectOne("com.zdp.domain.Order.selectOrderById", "O_00001");
System.out.println(order.getPerson().getName());
}
}