在基于 MVC 設(shè)計(jì)模式的 JAVA WEB 應(yīng)用中,Hibernate 可以作為模型層/數(shù)據(jù)訪問(wèn)層。它通過(guò)配置文件(hibernate.properties 或 hibernate.cfg.xml)和映射文件(***.hbm.xml)把 JAVA 對(duì)象或 PO(Persistent Object,持久化對(duì)象)映射到數(shù)據(jù)庫(kù)中的數(shù)據(jù)庫(kù),然后通過(guò)操作 PO,對(duì)數(shù)據(jù)表中的數(shù)據(jù)進(jìn)行增,刪,改,查等操作。 除配置文件,映射文件和持久化類外,Hibernate 的核心組件包括以下幾部分: a)Configuration 類:用來(lái)讀取 Hibernate 配置文件,并生成 SessionFactory 對(duì)象。 b)SessionFactory 接口:產(chǎn)生 Session 實(shí)例工廠。 c)Session 接口:用來(lái)操作 PO。它有 get(),load(),save(),update()和 delete()等方法用來(lái)對(duì) PO 進(jìn)行加載,保存,更新及刪除等操作。它是 Hibernate 的核心接口。 d)Query 接口:用來(lái)對(duì) PO 進(jìn)行查詢操。它可以從 Session 的 createQuery()方法生成。 e)Transaction 接口:用來(lái)管理 Hibernate 事務(wù),它主要方法有 commit()和 rollback(),可以從 Session 的 beginTrancation()方法生成。
持久化對(duì)象可以是普通的 Javabeans,惟一特殊的是它們與(僅一個(gè))Session 相關(guān)聯(lián)。 JavaBeans 在 Hibernate 中存在三種狀態(tài):
Hibernate 的運(yùn)行過(guò)程如下: A:應(yīng)用程序先調(diào)用 Configration 類,該類讀取 Hibernate 的配置文件及映射文件中的信息,并用這些信息生成一個(gè) SessionFactpry 對(duì)象。 B:然后從 SessionFactory 對(duì)象生成一個(gè) Session 對(duì)象,并用 Session 對(duì)象生成 Transaction 對(duì)象;可通過(guò) Session 對(duì)象的 get(),load(),save(),update(),delete()和 saveOrUpdate()等方法對(duì) PO 進(jìn)行加載,保存,更新,刪除等操作;在查詢的情況下,可通過(guò) Session 對(duì)象生成一個(gè) Query 對(duì)象,然后利用 Query 對(duì)象執(zhí)行查詢操作;如果沒有異常,Transaction 對(duì)象將提交這些操作結(jié)果到數(shù)據(jù)庫(kù)中。
Hibernate 的運(yùn)行過(guò)程如下圖:
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Hibernate 簡(jiǎn)單示例: 數(shù)據(jù):
create table T_register
(
id int primary key,
userName varchar(30),
userPwd varchar(30),
sex varchar(10),
age int
)
視圖層:注冊(cè)頁(yè)面 register.jsp
<%@ page language="java" contentType="text/html; charset=GBK"
pageEncoding="GBK"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GBK">
<title>Insert title here</title>
</head>
<body>
<form action="servlet/RegisterServlet" method="POST">
用戶名:<input type="text" name="userName" /><BR>
密 碼:<input type="text" name="userPwd" /><BR>
性 別:<input type="text" name="sex" /><BR>
年 齡:<input type="text" name="age" /><BR>
<input type="submit" value="save" />
</form>
</body>
</html>
設(shè)計(jì)持久化類 TRegister.java
package hibernate.PO;
/**
* 持久化類
*/
public class TRegister implements java.io.Serializable {
// Fields
private Integer id;
private String userName;
private String userPwd;
private String sex;
private Integer age;
// Constructors
/** default constructor */
public TRegister() {
}
/** minimal constructor */
public TRegister(Integer id) {
this.id = id;
}
/** full constructor */
public TRegister(Integer id, String userName, String userPwd, String sex, Integer age) {
this.id = id;
this.userName = userName;
this.userPwd = userPwd;
this.sex = sex;
this.age = age;
}
// Property accessors
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUserName() {
return this.userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getUserPwd() {
return this.userPwd;
}
public void setUserPwd(String userPwd) {
this.userPwd = userPwd;
}
public String getSex() {
return this.sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Integer getAge() {
return this.age;
}
public void setAge(Integer age) {
this.age = age;
}
}
設(shè)計(jì) Hibernate 配置文件 hibernate.cfg.xml
<?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>
<property name="connection.username">root</property>
<property name="connection.url">
jdbc:mysql://localhost:3306/study
</property>
<property name="dialect">
org.hibernate.dialect.MySQLDialect
</property>
<property name="myeclipse.connection.profile">MySQL5.0</property>
<property name="connection.password">root</property>
<property name="connection.driver_class">
org.gjt.mm.mysql.Driver
</property>
<property name="show_sql">true</property>
<mapping resource="hibernate/PO/TRegister.hbm.xml" />
</session-factory>
</hibernate-configuration>
設(shè)計(jì)映射文件 TRegister.hbm.xml
TRegister.hbm.xml 設(shè)計(jì) hibernate 基礎(chǔ)類 HibernateUtil.java
package hibernate;
/**
* hibernate 基礎(chǔ)類
* @author fengyan
* date 2007-01-09 02:32
*/
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
private static final SessionFactory sessionFactory;
static
{
try
{
Configuration config = new Configuration().configure("/hibernate/hibernate.cfg.xml");
sessionFactory = config.buildSessionFactory();
}
catch(Throwable e)
{
throw new ExceptionInInitializerError(e);
}
}
public static final ThreadLocal session = new ThreadLocal();
public static Session currentSession() throws HibernateException
{
Session s = (Session)session.get();
//Open a new Session,if this Thread has none yet
if(s == null || !s.isOpen())
{
s = sessionFactory.openSession();
session.set(s);
}
return s;
}
public static void closeSession() throws HibernateException
{
Session s = (Session)session.get();
session.set(null);
if(s != null)
s.close();
}
}
設(shè)計(jì)控制類
package hibernate.servlet;
/**
* @author fengyan
* date 2007-01-09 02:44
* 設(shè)計(jì)Hibernate控制類
*/
import hibernate.HibernateUtil;
import hibernate.PO.TRegister;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;
public class RegisterServlet extends HttpServlet {
private static final String CONTENT_TYPE = "text/html;charset=GBK";
public void init() throws ServletException {
// Put your code here
}
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType(CONTENT_TYPE);
request.setCharacterEncoding("GBK");
PrintWriter out = response.getWriter();
String userName = request.getParameter("userName");
String userPwd = request.getParameter("userPwd");
String sex = request.getParameter("sex");
int age = Integer.parseInt(request.getParameter("age"));
TRegister rg = new TRegister();
rg.setAge(age);
rg.setSex(sex);
rg.setUserName(userName);
rg.setUserPwd(userPwd);
Session session = HibernateUtil.currentSession();//生成Session實(shí)例
Transaction tx = session.beginTransaction();
try
{
session.save(rg); //保存持久類對(duì)象
tx.commit(); //提交到數(shù)據(jù)庫(kù)
session.close();
response.sendRedirect("registerOK.jsp");
}
catch(HibernateException e)
{
e.printStackTrace();
tx.rollback();
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}
編譯----->打包----->運(yùn)行----->OK!