Hibernate JPA的使用

今天學習了Hibernate JPA ，也就是元註解吧，現在總結一下：
hibernate.cfg.xml 的配置：

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
          "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<!-- Generated by MyEclipse Hibernate Tools.                   -->
<hibernate-configuration>

    <session-factory>
    <!-- 顯示實際操作數據庫時的SQL -->  
        <property name="show_sql">true</property> 
         <property name="dialect">org.hibernate.dialect.Oracle9Dialect</property> 
        <!--<property name="dialect">org.hibernate.dialect.OracleDialect</property>-->
        <property name="connection.url">jdbc:oracle:thin:@192.9.206.168:1521:orcl</property>
        <property name="connection.username">omsystem</property>
        <property name="connection.password">tj123456</property>
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="myeclipse.connection.profile">orcl</property>
        <!--<mapping resource="Struts2/Dao/TTestUser.hbm.xml"/>-->

        <!-- 實體類 -->
    	<mapping class="Struts2.Dao.d.TTestUser"/>
    </session-factory> 
</hibernate-configuration>

使用元註解就省去了TTestUser.hbm.xml這種文件的配置了，
只需要在JavaBean中加註解就可以了：
TTestUser.java 這個文件可以通過MyEclipse自動生成：

package Struts2.Dao.d;

import javax.persistence.Column;

/**
 * TTestUser entity. @author MyEclipse Persistence Tools
 */
@SuppressWarnings("serial")
@Entity
@Table(name = "T_TEST_USER")
public class TTestUser implements java.io.Serializable {
	// Fields
	private String id;
	private String name;
	private String pwd;
	private String sex;
	// Constructors

	/** default constructor */
	public TTestUser() {
	}

	/** minimal constructor */
	public TTestUser(String id) {
		this.id = id;
	}

	/** full constructor */
	public TTestUser(String id, String name, String pwd, String sex) {
		this.id = id;
		this.name = name;
		this.pwd = pwd;
		this.sex = sex;
	}

	// Property accessors
	@Id
	@Column(name = "ID", unique = true, nullable = false, length = 20)
	public String getId() {
		return this.id;
	}

	public void setId(String id) {
		this.id = id;
	}

	@Column(name = "NAME", length = 30)
	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Column(name = "PWD", length = 30)
	public String getPwd() {
		return this.pwd;
	}

	public void setPwd(String pwd) {
		this.pwd = pwd;
	}

	@Column(name = "SEX", length = 20)
	public String getSex() {
		return this.sex;
	}

	public void setSex(String sex) {
		this.sex = sex;
	}

}

幫助類HibernateDao.java 文件：

package Struts2.Util;

import org.hibernate.HibernateException;

public class HibernateDao {
	protected SessionFactory sessionFactory;// 會話工廠，用於創建會話
	protected Session session;// hibernate會話
	protected Transaction transaction; // hiberante事務


	private static AnnotationConfiguration configuration = new AnnotationConfiguration();


	public HibernateDao() throws HibernateException {
		this.initHibernate();
	}

	// 幫助方法
	protected void initHibernate() throws HibernateException {

		// 裝載配置，構造SessionFactory對象
		//sessionFactory = new Configuration().configure().buildSessionFactory();
		sessionFactory = configuration.configure().buildSessionFactory();
	}

	/**
	 *開始一個hibernate事務
	 */
	protected void beginTransaction() throws HibernateException {
		session = sessionFactory.openSession();
		transaction = session.beginTransaction();
	}

	/**
	 *結束一個hibernate事務。
	 */
	protected void endTransaction(boolean commit) throws HibernateException {

		if (commit) {
			transaction.commit();
		} else {
			// 如果是隻讀的操作，不需要commit這個事務。
			transaction.rollback();
		}
		session.close();
	}

}

這個文件主要注意的是 裝載配置，構造SessionFactory對象//sessionFactory = new Configuration().configure().buildSessionFactory();
需要修改爲
private static AnnotationConfiguration configuration = new AnnotationConfiguration();
sessionFactory = configuration.configure().buildSessionFactory();
最後開始測試吧：

package Struts2.Action;

import Struts2.Dao.d.TTestUser;
import Struts2.Server.TestUserService;

public class TestUserAction {
	public static void main(String[] args){
		TestUserService tu = new TestUserService();
		TTestUser tuser= new TTestUser();
		tuser.setId("3");
		tuser.setName("劉利明3");
		tuser.setPwd("1233");
		tuser.setSex("男3");
		tu.addUser(tuser);
	}

}

到這裏就結束了，要導入AnnotationConfiguration 的jar包。