Struts2边学边练(3)-Struts2集成Hibernate完成CRUD操作

Struts2边学边练(3)-Struts2集成Hibernate完成CRUD操作

在这个项目中,准备用Struts2集成hibernate来完成数据库的简单CRUD操作,暂时不涉及集成spring。项目需要的lib文件：
antlr-2.7.6.jar
cglib-nodep-2.1_3.jar
commons-collections-3.1.jar
commons-logging-1.0.4.jar
dom4j-1.6.1.jar
ehcache-1.2.3.jar
freemarker-2.3.8.jar
hibernate3.jar
javassist-3.4.GA.jar
jta-1.1.jar
log4j-1.2.15.jar
mysql-connector-java-5.1.7-bin.jar
ognl-2.6.11.jar
servlet-api.jar
slf4j-api-1.5.6.jar
slf4j-log4j12-1.5.6.jar
struts2-core-2.0.14.jar
xwork-2.0.7.jar

在这个系统中将完成User对象的增、删、改、查功能。Uer对象的属性有id，name和password。

将分为如下几个步骤来完成：

1.编写Hibernate工具类
2.编写Hibernate拦截器控制事务
3.编写DAO类
4.编写User对象和hibernate映射文件
5.编写UserAction类
6.编写所需的listUser.jsp和editUser.jsp页面
7.编写struts配置文件
8.配置web.xml文件
9.发布测试

首先新建一个web project项目Struts2Hibernate，将上面所需的jar全部复制到WEB-INF下的lib文件夹中。

1.编写Hibernate工具类：

首先编写hibernate.cfg.xml文件，文件放在src目录下。此文件主要配置hibernate的数据库连接和事务管理。

<? 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" >

< hibernate-configuration >

     < session-factory >

         < property  name ="hibernate.connection.driver_class" > com.mysql.jdbc.Driver </ property >
        
         < property  name ="hibernate.connection.url" > jdbc:mysql://localhost:3306/test </ property >
        
         < property  name ="hibernate.connection.username" > root </ property >
        
         < property  name ="hibernate.connection.password" ></ property >
        
         < property  name ="dialect" > org.hibernate.dialect.MySQLDialect </ property >
        
         < property  name ="hibernate.current_session_context_class" > thread </ property >
        
         < property  name ="hibernate.transaction.JDBCTransactionFactory" >
            org.hibernate.transaction.JDBCTransactionFactory
         </ property >

         <!--  Echo all executed SQL to stdout  -->
         < property  name ="show_sql" > true </ property >

         <!--  Drop and re-create the database schema on startup  -->
         < property  name ="hbm2ddl.auto" > create </ property >

         < mapping  resource ="com/hibernate/domain/User.hbm.xml" />

     </ session-factory >

</ hibernate-configuration >

接着编写HibernateUtil类，用于获取SessionFactory实例。此类可以在hibernate-distribution-3.3.1.GA包的\project\tutorials下找到。

package  com.hibernate.util;

import  org.hibernate.SessionFactory;
import  org.hibernate.cfg.Configuration;

public   class  HibernateUtil  {
    
    private static final SessionFactory sessionFactory;

    static {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
            sessionFactory = new Configuration().configure().buildSessionFactory();
        } catch (Throwable ex) {
            // Make sure you log the exception, as it might be swallowed
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
}

接着编写一个ExportDB类，方便用户直接将写好的hibernate映射表结构创建到数据库中。此类可以单独直接运行。

package  com.hibernate.util;

import  org.hibernate.cfg.Configuration;
import  org.hibernate.tool.hbm2ddl.SchemaExport;

public   class  ExportDB  {

    public static void main(String[] args) {
        
          Configuration cf =   new Configuration().configure();
          
          SchemaExport se =   new SchemaExport(cf);
          se.create(false, true);
        }
}

2.编写Hibernate拦截器控制事务
编写一个SessionInterceptor类来解决hibernate的lazyInitializationException。主要是采用过滤器的方式，在请求到达目标资源之前开始事务，在目标资源响应之后结束事务，来支持请求/响应模式所需的长事务。为了能执行此filter，需要在web.xml中增加filter。

package  com.hibernate.web;

import  java.io.IOException;

import  javax.servlet.Filter;
import  javax.servlet.FilterChain;
import  javax.servlet.FilterConfig;
import  javax.servlet.ServletException;
import  javax.servlet.ServletRequest;
import  javax.servlet.ServletResponse;

import  org.hibernate.SessionFactory;
import  org.hibernate.StaleObjectStateException;


import  com.hibernate.util.HibernateUtil;

public   class  SessionInterceptor  implements  Filter   {

    private SessionFactory sf = null;

    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        
        try{
            if (sf.getCurrentSession()==null){
                sf.openSession();
            }else{
                sf.getCurrentSession().beginTransaction();        
            }
            chain.doFilter(request, response);
            sf.getCurrentSession().getTransaction().commit();
        }catch(StaleObjectStateException ex){
            throw ex;
        }catch(Throwable tx){
            tx.printStackTrace();
            try{
                if(sf.getCurrentSession().getTransaction().isActive()){
                    sf.getCurrentSession().getTransaction().rollback();
                }
            }catch(Throwable rbEx){
                System.err.println(rbEx.toString());
            }
        }
    }

    public void init(FilterConfig arg0) throws ServletException {    
        sf = HibernateUtil.getSessionFactory();
    }
    
    public void destroy() {
        
    }

}

3.编写DAO类

编写一个DAOFactorty类用于屏蔽具体的DAO实现。

package  com.hibernate.dao;

public   abstract   class  DaoFactory  {

    private static final DaoFactory daoFactory = new HibernateDaoFactory();
    
    public static DaoFactory getInstance(){
        
        return daoFactory;
    }
    
    public abstract UserDao getUserDao();
}

编写HibernateDaoFactory工厂类，获得具体的DAO实现类。

package  com.hibernate.dao;

import  org.hibernate.Session;

import  com.hibernate.dao.impl.UserDaoImpl;
import  com.hibernate.util.HibernateUtil;

public   class  HibernateDaoFactory  extends  DaoFactory  {

    public UserDao getUserDao(){
        UserDao userdao = new UserDaoImpl(getCurrentSession());
        return userdao;
    }
    
    private Session getCurrentSession(){
        return HibernateUtil.getSessionFactory().getCurrentSession();
    }
}

编写UserDAO接口，便于不让上层依赖具体的DAO实现类。

package  com.hibernate.dao;

import  java.util.List;
import  com.hibernate.domain.User;

public   interface  UserDao  {
  
    public User findById(Integer id);
    public List<User> findAll();
    public void makePersistent(User user);
    public void delete(Integer id);
}

编写具体的实现类UserDaoImpl类

package  com.hibernate.dao.impl;

import  java.util.List;

import  org.hibernate.Session;

import  com.hibernate.dao.UserDao;
import  com.hibernate.domain.User;

public   class  UserDaoImpl  implements  UserDao  {

    private Session session ;
    
    public UserDaoImpl(Session session) {
        this.session = session;
    }
    
    public Session getSession() {
        return session;
    }

    public void delete(Integer id) {
        session.delete(getSession().get(User.class, id));
    }

    public List<User> findAll() {
        return session.createCriteria(User.class).list();
    }

    public User findById(Integer id) {
        return (User)session.get(User.class, id);
    }

    public void makePersistent(User user) {
        session.saveOrUpdate(user);
    }

}

4.编写User对象和hibernate映射文件

编写领域对象User。

package  com.hibernate.domain;

public   class  User  {
 
    private int id;
    
    private String name;
    
    private String password;

    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 String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
    
}

对上述领域对象编写hibernate映射文件User.hbm.xml

<? xml version="1.0" ?>
<! DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >

< hibernate-mapping  package ="com.hibernate.domain" >

     < class  name ="User"  table ="user" >
         < id  name ="id"  column ="id" >
             < generator  class ="native" />
         </ id >
         < property  name ="name" />
         < property  name ="password" />
     </ class >

</ hibernate-mapping >

5.编写UserAction类

在UserAction中完成User对象的CRUD相关函数的开发。同时需要创建3个属性，users,user,id

package  com.struts2.action;

import  java.util.List;

import  com.hibernate.dao.DaoFactory;
import  com.hibernate.domain.User;
import  com.opensymphony.xwork2.ActionSupport;
import  com.opensymphony.xwork2.Preparable;


public   class  UserAction  extends  ActionSupport  implements  Preparable  {

    private static final long serialVersionUID = -1057922687577124881L;
    
    private List<User> users;
    private User user;
    private Integer id;
    
    public List<User> getUsers() {
        return users;
    }

    public void setUsers(List<User> users) {
        this.users = users;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public Integer getId() {
        return id;
    }

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

    public String list() throws Exception{
        users = DaoFactory.getInstance().getUserDao().findAll();
        return SUCCESS;
    }
    
    public String delete() throws Exception{
        if(id!=null){
          DaoFactory.getInstance().getUserDao().delete(id);
        }
        return SUCCESS;
    }
    
    public String save() throws Exception{
        DaoFactory.getInstance().getUserDao().makePersistent(user);
        return SUCCESS;
    }
    
    public void prepare() throws Exception{
        if(id!=null){
         user = DaoFactory.getInstance().getUserDao().findById(id);
        }
    }

}

6.编写所需的listUser.jsp和editUser.jsp页面
index.jsp如下：

<% @ page language = " java "  contentType = " text/html; charset=ISO-8859-1 "  pageEncoding = " ISO-8859-1 " %>
<% @ taglib prefix = " s "  uri = " /struts-tags " %>
<! DOCTYPE html PUBLIC  " -//W3C//DTD HTML 4.01 Transitional//EN "   " http://www.w3.org/TR/html4/loose.dtd " >

< html >
< head >
< title > Struts2Hibernate </ title >
</ head >
< body >
  Welcome to Struts2Hibernate Project
   < p >
   < a href = " listUser.jsp " > View all users </ a >
</ body >
</ html >

listUser.jsp如下

<% @ page language = " java "  contentType = " text/html; charset=ISO-8859-1 "
    pageEncoding = " ISO-8859-1 " %>
<% @ taglib prefix = " s "  uri = " /struts-tags " %>

<! DOCTYPE html PUBLIC  " -//W3C//DTD HTML 4.01 Transitional//EN "   " http://www.w3.org/TR/html4/loose.dtd " >

< html >
< head >
< title > Struts2Hibernate </ title >
</ head >
< body >
< table >
    < tr >
      < th > id </ th >
      < th > name </ th >
      < th > password </ th >
    </ tr >
     < s:iterator value = " users " >
         < tr >
             < td >< a href = " <s:url action= " edit -% {id} " /> " >< s:property value = " id " /></ a ></ td >
             < td >< s:property value = " name "   /></ td >
             < td >< s:property value = " password "   /></ td >
             < td >< a href = " <s:url action= " delete -% {id} " /> " > delete </ a ></ td >
         </ tr >
     </ s:iterator >
</ table >
< p >
< a href = " <s:url action= " edit - "  includeParams= " none " /> " > create  new  user </ a >
</ body >
</ html >

editUser.jsp如下：

<% @ page language = " java "  contentType = " text/html; charset=ISO-8859-1 "  pageEncoding = " ISO-8859-1 " %>
<% @ taglib prefix = " s "  uri = " /struts-tags "   %>

<! 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=ISO-8859-1 " >
< title > Struts2Hibernate </ title >
</ head >
< body >
   < s: if  test = " user!=null " >
     < s:text id = " title "  name = " edit user " />
   </ s: if >
   < s: else >
     < s:text id = " title "  name = " create user " />
   </ s: else >
  
   < s:property value = " #title " />
  
   < s:form action = " save "  method = " post " >
      < s:hidden name = " user.id "  name = " user.id "  value = " %{user.id} " ></ s:hidden >
      < s:textfield label = " name "  name = " user.name "  value = " %{user.name} " ></ s:textfield >
      < s:password label = " password "  name = " user.password "  value = " %{user.password} " ></ s:password >
      < s:submit value = " save " ></ s:submit >
   </ s:form >
</ body >
</ html >

7.编写struts配置文件struts.xml

<? xml version="1.0" encoding="UTF-8"  ?>
<! DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd" >

< struts >
     < constant  name ="struts.i18n.encoding"  value ="GBK"   />
    
     < package  name ="default"  extends ="struts-default" >
         < action  name ="list"  class ="com.struts2.action.UserAction"  method ="list" >
             < result  name ="success" > /listUser.jsp </ result >
             < interceptor-ref  name ="basicStack"   />
         </ action >
 
         < action  name ="edit-*"  class ="com.struts2.action.UserAction" >
             < param  name ="id" > {1} </ param >
             < result > /editUser.jsp </ result >
             < interceptor-ref  name ="static-params"   />
             < interceptor-ref  name ="basicStack"   />
         </ action >
        
         < action  name ="save"  class ="com.struts2.action.UserAction"  method ="save" >
             < result  name ="input" > /editUser.jsp </ result >
             < result  type ="redirect" > list.action </ result >
         </ action >
        
         < action  name ="delete-*"  class ="com.struts2.action.UserAction"  method ="delete" >
             < param  name ="id" > {1} </ param >
             < result  type ="redirect" > list.action </ result >
             < interceptor-ref  name ="static-params"   />
         </ action >
        
     </ package >

</ struts >

8.配置web.xml文件
注意：SessionInterceptor的filter要放在第一个filer的位置。

<? xml version="1.0" encoding="UTF-8" ?>
< web-app  id ="WebApp_ID"  version ="2.4"  xmlns ="http://java.sun.com/xml/ns/j2ee"  xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation ="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" >
    
     < display-name > Struts2Hibernate </ display-name >
    
     < welcome-file-list >
         < welcome-file > index.jsp </ welcome-file >
     </ welcome-file-list >
    
     < filter >
         < filter-name > SessionInterceptor </ filter-name >
         < filter-class > com.hibernate.web.SessionInterceptor </ filter-class >
     </ filter >
     < filter-mapping >
         < filter-name > SessionInterceptor </ filter-name >
         < url-pattern > /* </ url-pattern >
     </ filter-mapping >
    
     < filter >
         < filter-name > struts2 </ filter-name >
         < filter-class > org.apache.struts2.dispatcher.FilterDispatcher </ filter-class >
     </ filter >
     < filter-mapping >
         < filter-name > struts2 </ filter-name >
         < url-pattern > /* </ url-pattern >
     </ filter-mapping >
    
</ web-app >

9.发布测试