hibernate--联合主键--annotation

有3种方式:

1.@Embeddedable

2.@EmbeddedId

3. @IdClass

2,3 最常用

一, @Embeddedable

1.新建TeacherPK.java, 加入@Embeddable:

package com.bjsxt.hibernate;

import javax.persistence.Embeddable;

@Embeddable
public class TeacherPK implements java.io.Serializable{
    private int id;
    private String name;
    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. 重写Teacher.java, 加入pk对象, 并设置@Id:

package com.bjsxt.hibernate;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="_Teacher")
public class Teacher {
	private TeacherPK pk;
	@Id
	public TeacherPK getPk() {
		return pk;
	}
	public void setPk(TeacherPK pk) {
		this.pk = pk;
	}
	private String title;

	public String getTitle() {
		return title;
	}
	public void setTitle(String title) {
		this.title = title;
	}
}

3. 重写junit测试方法:

@Test
	public void testTeacherSave() {
		TeacherPK pk=new TeacherPK();
		pk.setId(1);
		pk.setName("lisi");

		Teacher t =new Teacher();
		t.setPk(pk);
		t.setTitle("higfdfsdfsadh");

		Session session =  sf.openSession();
		session.beginTransaction();
		session.save(t);
		session.getTransaction().commit();
		session.close();
	}

二: @EmbeddedId

1. 去掉TeacherPK.java的@Embeddable:

package com.bjsxt.hibernate;

import javax.persistence.Embeddable;

public class TeacherPK implements java.io.Serializable{
    private int id;
    private String name;
    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. Teacher.java里@Id的地方改成@EmbeddedId

package com.bjsxt.hibernate;

import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.IdClass;
import javax.persistence.Table;

@Entity
@Table(name="_Teacher")
//@IdClass(value=TeacherPK.class)
public class Teacher {
	private TeacherPK pk = new TeacherPK();
	@EmbeddedId
	public TeacherPK getPk() {
		return pk;
	}
	public void setPk(TeacherPK pk) {
		this.pk = pk;
	}
	private String title;	

	public String getTitle() {
		return title;
	}
	public void setTitle(String title) {
		this.title = title;
	}
}

　　

3. test方法:

@Test
	public void testTeacherSave() {
		TeacherPK pk=new TeacherPK();
		pk.setId(2);
		pk.setName("lisi");

		Teacher t =new Teacher();
		t.setPk(pk);
		t.setTitle("higfdfsdfsadh");

		Session session =  sf.openSession();
		session.beginTransaction();
		session.save(t);
		session.getTransaction().commit();
		session.close();
	}

　　

三, @IdClass

1. TeacherPK.java:

package com.bjsxt.hibernate;

import javax.persistence.Embeddable;

public class TeacherPK implements java.io.Serializable{
    private int id;
    private String name;
    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. Teacher.java里类前加入IdClass:

package com.bjsxt.hibernate;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.IdClass;
import javax.persistence.Table;

@Entity
@Table(name="_Teacher")
@IdClass(value=TeacherPK.class)
public class Teacher {
	private int id;
	private String name;
	private String title;

	@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;
	}
	public String getTitle() {
		return title;
	}
	public void setTitle(String title) {
		this.title = title;
	}
}

3. junit的测试方法;

@Test
	public void testTeacherSave() {
		Teacher t =new Teacher();
		t.setId(1);
		t.setName("zhagnsan");
		t.setTitle("higfdfsdfsadh");

		Session session =  sf.openSession();
		session.beginTransaction();
		session.save(t);
		session.getTransaction().commit();
		session.close();
	}