hibernate 联合主键

Hibernate 联合主键有三种写法 ：

第一种：使用 @Embeddable注解 

import java.io.Serializable;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class TestPerson implements Serializable{
	private static final long serialVersionUID = 1L;
	private String password;
	private String email;
	private String adress;
	@Id
	private TestPersonPk testPersonPk;
	
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public String getAdress() {
		return adress;
	}
	public void setAdress(String adress) {
		this.adress = adress;
	}
	public TestPersonPk getTestPersonPk() {
		return testPersonPk;
	}
	public void setTestPersonPk(TestPersonPk testPersonPk) {
		this.testPersonPk = testPersonPk;
	}
	
	
}

import java.io.Serializable;

import javax.persistence.Embeddable;

@Embeddable
public class TestPersonPk implements Serializable{
	private static final long serialVersionUID = 1L;
	private Integer id;
	private String name;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	@Override
	public int hashCode() {
		return super.hashCode();
	}
	@Override
	public boolean equals(Object obj) {
		if(obj instanceof TestPersonPk){
			TestPersonPk testPersonPk = (TestPersonPk) obj;
			if(testPersonPk.getId().equals(this.getId()) && testPersonPk.getName().equals(this.getName())){
				return true;
			}
		}
		return false;
	}
	
}

创建表后：

查看创建表的语句：show create table testperson; 可以看到

CREATE TABLE `testperson` (

  `id` int(11) NOT NULL,

  `name` varchar(255) NOT NULL,

  `adress` varchar(255) DEFAULT NULL,

  `email` varchar(255) DEFAULT NULL,

  `password` varchar(255) DEFAULT NULL,

  PRIMARY KEY (`id`,`name`)

) 

第二种：使用 @EmbeddedId  注解

import java.io.Serializable;

import javax.persistence.EmbeddedId;
import javax.persistence.Entity;

@Entity
public class TestPerson implements Serializable{
	private static final long serialVersionUID = 1L;
	private String password;
	private String email;
	private String adress;
	@EmbeddedId 
	private TestPersonPk testPersonPk;
	
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public String getAdress() {
		return adress;
	}
	public void setAdress(String adress) {
		this.adress = adress;
	}
	public TestPersonPk getTestPersonPk() {
		return testPersonPk;
	}
	public void setTestPersonPk(TestPersonPk testPersonPk) {
		this.testPersonPk = testPersonPk;
	}
	
	
}

import java.io.Serializable;

public class TestPersonPk implements Serializable{
	private static final long serialVersionUID = 1L;
	private Integer id;
	private String name;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	@Override
	public int hashCode() {
		return super.hashCode();
	}
	@Override
	public boolean equals(Object obj) {
		if(obj instanceof TestPersonPk){
			TestPersonPk testPersonPk = (TestPersonPk) obj;
			if(testPersonPk.getId().equals(this.getId()) && testPersonPk.getName().equals(this.getName())){
				return true;
			}
		}
		return false;
	}
	
}

创建结果和第一种一样

第三种：@IdClass(XXX.class)注解

import java.io.Serializable;

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

@Entity
@IdClass(TestPersonPk.class) 
public class TestPerson implements Serializable{
	private static final long serialVersionUID = 1L;
	private String password;
	private String email;
	private String adress;
	
	private Integer id;
	private String name;
	
	@Id
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	@Id
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public String getAdress() {
		return adress;
	}
	public void setAdress(String adress) {
		this.adress = adress;
	}
	
	
}

import java.io.Serializable;

public class TestPersonPk implements Serializable{
	private static final long serialVersionUID = 1L;
	private Integer id;
	private String name;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	@Override
	public int hashCode() {
		return super.hashCode();
	}
	@Override
	public boolean equals(Object obj) {
		if(obj instanceof TestPersonPk){
			TestPersonPk testPersonPk = (TestPersonPk) obj;
			if(testPersonPk.getId().equals(this.getId()) && testPersonPk.getName().equals(this.getName())){
				return true;
			}
		}
		return false;
	}
	
}

 
 第三种结果和前两种一样；

注：使用联合主键要重写equals 和hashCode方法；