JPA入门（三）双向一对一

package org.jzkangta.onetoone;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
/**
 * 选择了Person是关系维护端，所以Person为负责外键的更新
 * @author Administrator
 *
 */
@Entity
public class Person {

	@Id
	@GeneratedValue
	private int id;
	
	@Column(nullable=false)
	private String name;
	
	@OneToOne(cascade=CascadeType.ALL,optional=false)
	@JoinColumn(name="idCard_id") //关系维护端设置外键
	private IDCard idCard;
	
	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 IDCard getIdCard() {
    	return idCard;
    }
	public void setIdCard( IDCard idCard ) {
    	this.idCard = idCard;
    }
	
}


package org.jzkangta.onetoone;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToOne;

@Entity
public class IDCard {

	@Id
	@GeneratedValue
	private int id;
	
	@Column(length=18,nullable=false)
	private String idNumber;
	
	@OneToOne(mappedBy="idCard",cascade={CascadeType.MERGE,CascadeType.PERSIST,CascadeType.REFRESH},optional=false,fetch=FetchType.EAGER)//被维护端，idCard为维护端里的属性,optional=false不允许为null
	private Person person;
	
	
	public int getId() {
    	return id;
    }
	public void setId( int id ) {
    	this.id = id;
    }
	public String getIdNumber() {
    	return idNumber;
    }
	public void setIdNumber( String idNumber ) {
    	this.idNumber = idNumber;
    }
	public Person getPerson() {
    	return person;
    }
	public void setPerson( Person person ) {
    	this.person = person;
    }
	
}