jap单映射

/**
*
*/
package com.jpa.bean;

import java.util.Date;

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.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

/**
* @author DZC
* 2012-8-3下午8:12:03
*/
@Entity
@Table(name="user")
public class User {
    @Id
    @GeneratedValue()
private int id;
    @Column(length=20)
private String name;
    @Temporal(TemporalType.DATE)
private Date birthday;
    @Column(length=10)
private int age;
    @ManyToOne(cascade={CascadeType.ALL}, fetch = FetchType.EAGER)
    @JoinColumn(name="unit_id") //生成外键用
    private Unit unit;
   
public Unit getUnit() {
return unit;
}
public void setUnit(Unit unit) {
this.unit = unit;
}
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 Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}

}

Unit实体类
/**
*
*/
package com.jpa.bean;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumns;
import javax.persistence.OneToMany;
import javax.persistence.Table;

import com.sun.org.apache.bcel.internal.generic.NEW;

/**
* @author DZC
* 2012-8-4下午6:16:35
*/
@Entity
@Table(name="unit")
public class Unit {
@Id @GeneratedValue()
private int id;
@Column(length=10)
private  int developdepartment;//研发部
@Column(length=10)
private int marketdepartment; //市场部

public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getDevelopdepartment() {
return developdepartment;
}
public void setDevelopdepartment(int developdepartment) {
this.developdepartment = developdepartment;
}
public int getMarketdepartment() {
return marketdepartment;
}
public void setMarketdepartment(int marketdepartment) {
this.marketdepartment = marketdepartment;
}
}

Dao类：
/**
*
*/
package com.jpa.dao;

import java.util.Date;

import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;

import com.jpa.bean.Unit;
import com.jpa.bean.User;
import com.jpa.factory.JpaInIt;

/**
* @author DZC
* 2012-8-3下午8:26:01
*/
public class UserDao {

public static void main(String[] args) {
Unit unit=new Unit();
unit.setDevelopdepartment(0);
unit.setMarketdepartment(1);

User user=new User();
user.setName("丁志超");
user.setAge(20);
user.setBirthday(new Date());
user.setUnit(unit);
addUser(user);
}

static void addUser(User user){
EntityManager em=null;
EntityTransaction tx=null;
try {
em=JpaInIt.getEntityManager();
tx=em.getTransaction();
tx.begin();
em.persist(user);
tx.commit();
} catch (Exception e) {

}
finally
{
if (em!=null) {
em.close();
}
}
}

}