Hibernate的@GeneratedValue注解

1.新建一个java project项目，里面新建一个lib文件夹，lib文件夹里面放置要用的一些jar文件，然后全部选中导入到项目中去。整体的框架如下图所示：

2.Students.java里面的代码如下图所示：

package entity;

import java.io.Serializable;
import java.util.Date;

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

@Entity
@Table(name = "t_students", schema = "hibernate")
public class Students implements Serializable {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	private int sid;
	private String sname;
	private String gender;
	private Date birthday;
	private String major;

	private Address add;

	public Students() {

	}

	public Students(int sid, String sname, String gender, Date birthday,
			String major, Address add) {
		this.sid = sid;
		this.sname = sname;
		this.gender = gender;
		this.birthday = birthday;
		this.major = major;
		this.add = add;
	}

	public int getSid() {
		return sid;
	}

	public void setSid(int sid) {
		this.sid = sid;
	}

	public String getSname() {
		return sname;
	}

	public void setSname(String sname) {
		this.sname = sname;
	}

	public String getGender() {
		return gender;
	}

	public void setGender(String gender) {
		this.gender = gender;
	}

	public Date getBirthday() {
		return birthday;
	}

	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}

	public String getMajor() {
		return major;
	}

	public void setMajor(String major) {
		this.major = major;
	}

	public Address getAdd() {
		return add;
	}

	public void setAdd(Address add) {
		this.add = add;
	}

}

3.Address.java里面的代码：

 package entity;

 import javax.persistence.Embeddable;

 @Embeddable
 public class Address {

     private String postCode;
     private String address;
     private String phone;

     public Address() {

     }

     public String getPostCode() {
         return postCode;
     }

     public void setPostCode(String postCode) {
         this.postCode = postCode;
     }

     public String getAddress() {
         return address;
     }

     public void setAddress(String address) {
         this.address = address;
     }

     public String getPhone() {
         return phone;
     }

     public void setPhone(String phone) {
         this.phone = phone;
     }

 }

4.hibernate.cfg.xml里面的代码如下图所示：

 xml version="1.0" encoding="UTF-8"?>

         "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
         "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
 <hibernate-configuration>
     <session-factory>
         <property name="connection.driver_class">com.mysql.jdbc.Driverproperty>
         <property name="connection.url">jdbc:mysql://localhost:3306/hibernate?characterEncoding=utf-8property>
         <property name="dialect">org.hibernate.dialect.MySQLDialectproperty>
         <property name="connection.username">rootproperty>
         <property name="connection.password">rootproperty>
         <property name="show_sql">trueproperty>
         <property name="format_sql">trueproperty>
         <property name="hbm2ddl.auto">createproperty>
         <property name="hibernate.current_session_context_clss">threadproperty>

         <mapping class="entity.Students" />
     session-factory>
 hibernate-configuration>

5.TestStudents.java里面的代码如下图所示：

 package entity;

 import org.hibernate.SessionFactory;
 import org.hibernate.cfg.Configuration;
 import org.hibernate.service.ServiceRegistry;
 import org.hibernate.service.ServiceRegistryBuilder;
 import org.hibernate.tool.hbm2ddl.SchemaExport;
 import org.junit.Test;

 public class TestStudents {

     @Test
     public void testShemaExport() {
         Configuration config = new Configuration().configure();
         ServiceRegistry serviceRegistry = new ServiceRegistryBuilder()
                 .applySettings(config.getProperties()).buildServiceRegistry();
         SessionFactory sessionFactory = config
                 .buildSessionFactory(serviceRegistry);
         SchemaExport export = new SchemaExport(config);
         export.create(true, true);
     }

 }