SSH2 Step by Step- Step 4 - Struts2、Spring和Hibernate的整合

折騰了好幾天,終於把SSH2的框架搭起來,期間經歷的興奮,痛苦,猶豫...最終是領悟:太完美的要求,其實就是拖延...所以在以下的jar包的選擇上,跟前面幾篇的原則有了很大的區別:

  1. Struts包保持原樣。
  2. Spring 和hibernate的包按最大的導入,因爲少了個jar文件導致的錯誤查找,實在是這兩天最痛苦的事情。
  3. Hibernate從4.0降到3.6.8,原因是Hibernate4改變太大,我又不想在期初用Maven來更新Jar包.

上一篇中提到怎麼整合Struts2和hibernate,接下來,到了最最最關鍵的時刻,要把Spring融合進來...
Spring在MVC中的作用應該是C的功能,提供了一個對象的容器...

言歸正傳. 我們需要開始引入幾個Spring的包.

1. 下載Hibernate3.6.8的包,解壓後copy requred目錄下的所有的文件到lib目錄下,注意這裏有一個antlr2.7.7.jar的, 要替換掉原先struts引入的那個低版本(2.7.2)的jar文件。保險一點把jpa目錄下的那個jpa的jar包也copy(hibernate-jpa-2.0-api-1.0.1.Final.jar)
2.  導入struts2-spring-plugin-2.2.3.1.jar  (這個在Struts2的包裏面找),copy到WEB-INF/lib目錄下
3. 導入Spring的一些Jar包 : 導入spring 的dist 目錄下的所有的jar文件

接下來我們比較一下加入Spring有什麼變化:
  1. 配置web.xml, -- 一些Struts和Spring的啓動項會在這裏配置 
  2. 配置ApplicationContext.xml -- 刪除hibernate.cfg.xml, 將配置挪到這裏來做(增加SessionFactory和dataSource的設置),也就是由Spring來接管
  3. 增加POJO類和Hibernate的ORM映射文件(xxx.hbm.xml)  -- 個人建議,如果Table間的關係比較簡單,用annotation來避免重複維護ORM映射文件. 但是這裏還是按照傳統的做法。
  4. 編寫DAO接口和DAO實現類 -- 將接口和實現類分離的好處就不用我講了,(OO設計原則:將類的行爲和實現分離,面向接口編程)
  5. 將DAO的實現類的配置增加到ApplicationContext.xml中 -- 注意,Application中的Bean都是class,而不是interface.
  6. 增加業務類接口和實現類 -- (個人理解:DAO類只對應一個Table,但是業務類對應的可能是一個業務流程...歡迎扔磚)
  7. 增加Client端Jsp頁面
  8. 增加Action類,將jsp的請求轉發給業務處理類(其實這裏是轉給業務接口類)
  9. 修改struts.xml, 增加action的調用,這裏用了struts的僞調用,實際上action的請求和轉發由spring接管了 --- (struts2-spring-plugin-2.2.3.1.jar  )會幹這個活。
  10. 修改applicationContext.xml, 增加action bean

馬上開始:
1. 先把需要的jar包列一下:

2. web.xml文件的配置,增加struts2和spring的啓動項

<?xml version="1.0" encoding="UTF-8"?>
<web-app 
		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
		xmlns="http://java.sun.com/xml/ns/javaee" 
		xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
		xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
		id="WebApp_ID" version="2.5">
	
	<!-- Spring configuration -->
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>classpath:applicationContext*.xml</param-value>
	</context-param>
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
	
	<!-- Struts2 configuration -->
	<filter> 
         <filter-name>struts2</filter-name> 
         <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class> 
     </filter> 
     <filter-mapping> 
         <filter-name>struts2</filter-name> 
         <url-pattern>/*</url-pattern> 
     </filter-mapping> 
     
</web-app>

3. 配置ApplicationContext.xml -- 刪除hibernate.cfg.xml, 將配置挪到這裏來做(增加SessionFactory和dataSource的設置),也就是由Spring來接管,該文件放在src目錄下:
注意這裏我將一個applicationContext.xml分成了3部分,

  • 數據庫的連接串單獨放一個文件(dataSource.properties)
  • 平時不大會動的數據庫配置放到database.xml中
  • applicationContext.xml會導入上面的內容,我們可以集中在bean的設置上

applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/aop 
           http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd  
           http://www.springframework.org/schema/tx 
  		   http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

	<!-- Hibernate configuration -->
	<import resource="classpath:database.xml"/>
	
</beans>
database.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/aop 
           http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd  
           http://www.springframework.org/schema/tx 
  		   http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
	
	<bean id="configBean" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		<property name="location">
			<value>classpath:dataSource.properties</value>
		</property>
	</bean>
	<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
		<property name="driverClassName" value="${dataSource.driverClassName}" />
		<property name="url" value="${dataSource.url}" />
		<property name="username" value="${dataSource.username}" />
		<property name="password" value="${dataSource.password}" />
	</bean>
	<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
		<property name="dataSource" ref="dataSource" />
		<property name="hibernateProperties">
			<props>
				<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
				<prop key="hibernate.show_sql">true</prop>
			</props>
		</property>
		<property name="mappingResources">
			<list>
				<value>com/test/bean/User.hbm.xml</value>
			</list>
		</property>
	</bean>

	
</beans>    

dataSource.properties
dataSource.driverClassName=com.mysql.jdbc.Driver
dataSource.url=jdbc:mysql://localhost/test?characterEncoding=utf-8
dataSource.username=root
dataSource.password=root
4. 增加一個User的POJO類和Hibernate對應的映射文件.
package com.test.bean;

public class User {
	private Integer id;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	private String name;
	private String password;
	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;
	}
	
}

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>  
    <class name="com.test.bean.User" table="User" catalog="test">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="name" length="40" />
        </property>
        <property name="password" type="java.lang.String">
            <column name="password" length="40" />
        </property>
    </class>
</hibernate-mapping>

5. 編寫DAO接口和DAO實現
package com.test.dao;

import com.test.bean.User;

public interface UserDao {
	public User find(String name, String password);
	public User find(User user);
}

package com.test.daoImpl;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;

import com.test.bean.User;
import com.test.dao.UserDao;

public class UserDaoImpl implements UserDao {
	
	private SessionFactory sessionFactory;
	
	@Override
	public User find(String name, String password) {
		Session session = sessionFactory.openSession();
		String hql = "FROM User AS u WHERE u.name = :name AND u.password = :password";
		Query q = session.createQuery(hql);
		q.setString("name", name);
		q.setString("password", password);		
		List<User> list = q.list();
		session.close();
		if (list.size()==0)
			return null;
		else
			return list.get(0);
	}

	public SessionFactory getSessionFactory() {
		return sessionFactory;
	}

	public void setSessionFactory(SessionFactory sessionFactory) {
		this.sessionFactory = sessionFactory;
	}


	public User find(User user) {
		return find(user.getName(),user.getPassword());
	}

}
注意上面的sessionFactory是由Spring來負責注入和管理的,因此一定要有一個set的方法來加載sessionFactory對象。

6, 編寫業務接口和實現類
UserService接口
package com.test.service;

import com.test.bean.User;

public interface UserService {

	public boolean isLogin(User user);
	public boolean isLogin(String name, String password);
}
UserService實現類
package com.test.serviceImpl;

import com.test.bean.User;
import com.test.dao.UserDao;
import com.test.service.UserService;

public class UserServiceImpl implements UserService {
	private UserDao userDao;
	
	public boolean isLogin(User user) {
		return isLogin(user.getName(),user.getPassword());
	}

	public UserDao getUserDao() {
		return userDao;
	}

	public void setUserDao(UserDao userDao) {
		this.userDao = userDao;
	}

	@Override
	public boolean isLogin(String name, String password) {
		boolean isLogin = false;
		try
			{
			User u = userDao.find(name, password);
			if (u != null)
				{
				isLogin = true;
				}
			}
		catch (Exception e)
			{
			System.out.println("isLogin error\n" + e.getMessage());
			}
		return isLogin;
	}

}

6. 在applicatonContext.xml中配置bean
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/aop 
           http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd  
           http://www.springframework.org/schema/tx 
  		   http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

	<!-- Hibernate configuration -->
	<import resource="classpath:database.xml"/>
	
	<!-- struts beans -->
	<bean id="LoginAction" class="com.test.action.LoginAction" scope="prototype">
		<property name="userService" ref="userService" />
	</bean>
	
	<bean id="userDao" class="com.test.daoImpl.UserDaoImpl">
		<property name="sessionFactory" ref="sessionFactory"></property>
	</bean>
	
	<bean id="userService" class="com.test.serviceImpl.UserServiceImpl">
		<property name="userDao" ref="userDao"></property>
	</bean>

</beans>

7. 增加jsp頁面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s" %>
    
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
	<base href="<%=basePath%>">
	<title><s:text name="home.title" /></title>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="easyTalk">
	<meta http-equiv="description" content="This is my page">
</head>
<body>
	<s:form name="loginFrm" action="login">
		<s:textfield name="username" key="username"></s:textfield>
		<s:textfield name="password" key="password"></s:textfield>
		<s:submit label="submit"></s:submit>
	</s:form>
	<s:actionerror/>
</body>
</html>

8. 配置struts.xml, 注意這裏有兩個改動,a. 增加了一個常量,聲明objectFactory由Spring接管. b. action 的class屬性中,維護的是Spring的bean對象,而不是具體的class.
<?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.custom.i18n.resources" value="message"></constant>
	<constant name="struts.objectFactory" value="spring"></constant>
	<constant name="struts.devMode" value="true" />
	
	<package name="struts2" extends="struts-default">
		<action name="login" class="LoginAction">
			<result name="success" >loginresult.jsp</result>
			<result name="input">login.jsp</result>
			<result name="error">login.jsp</result>
		</action>
	</package>
	
</struts>

9. 增加action類,接受客戶端的響應
package com.test.action;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.test.service.UserService;

public class LoginAction extends ActionSupport {

		public String username;
		public String password;
		private UserService userService;
		
		public LoginAction()
		{
			System.out.println("initialize LoginAction......");
		}
		public void setUserService(UserService userService)
		{
			this.userService = userService;
		}
		
		public String execute()
		{
			if (true == this.userService.isLogin(username, password))
			{
				ActionContext.getContext().getSession().put("username", username);
				return SUCCESS;
			}else{
				super.addActionError(super.getText("loginfailed"));
				return ERROR;
			}
		}
		
		public void validate()
		{
			if ((null == username) || (0==username.length()))
			{
				super.addActionError(super.getText("warning.empty",new String[] {getText("username")}));
			}
			
			if ((null == password) || (0 == password.length()))
			{
				super.addActionError(super.getText("warning.empty",new String[] {getText("password")}));
				
			}
		}
}
10. 在applicationContext.xml中增加action的bean,請參考上面的xml文件,這裏略過。
11. 最後整個代碼的架構如下:



12. 測試登錄功能
Login 頁面:

登錄成功:

系統日誌:


測試通過............................................................

12. 總結:
  • 初期階段不要過分追求jar包的最小配置,否則會出現很多意料之外的錯誤.
  • Jar包的版本要小心,最後我無奈將Hibernate從4.0降回3.6.8, 因爲差異太大.
  • spring中bean的配置要小心,注入的時候是實現類,不是接口,名字也要注意,property name是引用對象的名字,而不是類的名字,這裏我就吃了一次虧,login的時候怎麼都說LoginAction對象找不到,其實是配置文件寫得有問題,結果Spring無法生成bean實例,這個錯誤很像Struts無法調用Spring的容器...但是其實是Spring容器無法生成Bean對象。

源代碼已上傳,請點擊此處下載


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