学步园

1

package com.bjsxt.hibernate;

import java.util.HashMap;
import java.util.Map;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.MapKey;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
@Table(name="t_group")
public class Group {
	private int id;
	private String name;
	//private Set<User> users = new HashSet<User>();
	
	/*private List<User> users = new ArrayList<User>();
	
	@OneToMany(mappedBy="group",
			cascade={CascadeType.ALL}
			)
	@OrderBy("name ASC")
	public List<User> getUsers() {
		return users;
	}
	public void setUsers(List<User> users) {
		this.users = users;
	}*/
	
	
	private Map<Integer, User> users = new HashMap<Integer, User>();
	
	@OneToMany(mappedBy="group", cascade=CascadeType.ALL)
	@MapKey(name="id")
	public Map<Integer, User> getUsers() {
		return users;
	}
	public void setUsers(Map<Integer, User> users) {
		this.users = users;
	}
	@Id
	@GeneratedValue
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
}

2

package com.bjsxt.hibernate;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name="t_user")
public class User {
	private int id;
	private String name;
	private Group group;
	@ManyToOne(cascade={CascadeType.ALL})
	public Group getGroup() {
		return group;
	}
	public void setGroup(Group group) {
		this.group = group;
	}
	@Id
	@GeneratedValue
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
}

3

package com.bjsxt.hibernate;

import java.util.Map;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class HibernateORMappingTest {
	private static SessionFactory sessionFactory;
	
	@BeforeClass
	public static void beforeClass() {
		//new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
		sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
	}
	@AfterClass
	public static void afterClass() {
		sessionFactory.close();
	}
	
	@Test
	public void testLoadGroup() {
		
		Session s = sessionFactory.getCurrentSession();
		s.beginTransaction();
		//User u = (User)s.load(User.class, 1);
		//u.setGroup(null);
		//s.delete(u);
		Group g = (Group)s.load(Group.class, 1);
		for(Map.Entry<Integer, User> entry : g.getUsers().entrySet()) {
			System.out.println(entry.getValue().getName());
		}
		//s.createQuery("delete from User u where u.id = 1").executeUpdate();
		s.getTransaction().commit();
		
	}
	
	@Test
	public void testSchemaExport() {
		new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
	}
	
	
	public static void main(String[] args) {
		beforeClass();
	}
}