使用AppFuse的七个理由: 学习Java开放源码工具并使用这些工具提高生产效率 - 编程入门网

测试代码：

1.package com.hb3.pack_16;2.3.import java.io.IOException;4.import java.sql.SQLException;5.
6.import org.hibernate.Session;7.import org.hibernate.SessionFactory;8.import org.hibernate.Transaction;9.import org.hibernate.cfg.Configuration;10.
11.import com.hb3.pack_16.model.Room;12.import com.hb3.pack_16.model.User;13.14.
15.public class BusinessService {16.
17.    public static void main(String[] args) throws IOException, SQLException {18.19.        Configuration config = new Configuration().configure();20.        SessionFactory sessionFactory = config.buildSessionFactory();21.        Session session = sessionFactory.openSession();22.
23.        Room room1 = new Room();24.        room1.setAddress("NTU-M8-419");25.        Room room2 = new Room();26.        room2.setAddress("NTU-G3-302");27.28.        User user1 = new User();29.        user1.setName("shenbin");30.        user1.setRoom(room1);31.32.        User user2 = new User();33.        user2.setName("chenyan");34.        user2.setRoom(room1);35.36.        User user3 = new User();37.        user3.setName("yangye");38.        user3.setRoom(room2);39.
40.        Transaction tx = session.beginTransaction();41.        session.save(user1);42.        session.save(user2);43.        session.save(user3);44.        tx.commit();45.
46.        User user = (User) session.load(User.class, new Integer(1));47.        System.out.println(user.getName());48.        System.out.println(user.getRoom().getAddress());49.
50.51.        session.close();52.        sessionFactory.close();53.    }54.}

hibernate3学习笔记(十七)｜关系映射：多对一(4)

在<many-to-one>的设定中：

cascade表示操作时的级联关系。表示主控方在进行增删改操作时，被控方是否进行相关操作。

outer-join表示查询时是否使用外连接查询方式。

outer-join为true的时候，生成的查询SQL为：

Hibernate: select user0_.id as id1_, user0_.name as name0_1_, user0_.room_id as room3_0_1_, room1_.id as id0_, room1_.address as address1_0_ from user user0_ left outer join room room1_ on user0_.room_id=room1_.id where user0_.id=? outer-join为false的时候，生成的查询SQL为：Hibernate: select user0_.id as id0_, user0_.name as name0_0_, user0_.room_id as room3_0_0_ from user user0_ where user0_.id=? Hibernate: select room0_.id as id0_, room0_.address as address1_0_ from room room0_ where room0_.id=?

不过最好使用fetch属性来表示，及fetch="join"或者fetch="select"。

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