Q一Q?br> 下列是所有文Ӟ(x)
CheckRequestProcessor RequestProcessorcd
UserLoginAction action
userLogin.jsp
successfullyLogin.jsp
failureLogin.jsp
manage.jsp
accessDenied.jsp
Q二Q文件的内容Q?br>
2.1Q?br> struts-config.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.1//EN" "http://jakarta.apache.org/struts/dtds/struts-config_1_1.dtd">
<struts-config>
<data-sources />
<form-beans >
<form-bean name="userLoginForm" type="cn.edu.scut.www.ginge.form.UserLoginForm" />
</form-beans>
<global-exceptions />
<global-forwards />
<action-mappings >
<action
attribute="userLoginForm"
input="/form/userLogin.jsp"
name="userLoginForm"
path="/userLogin"
scope="request"
type="cn.edu.scut.www.ginge.action.UserLoginAction">
<forward name="successfullyLogin" path="/successfullyLogin.jsp" />
<forward name="failureLogin" path="/failureLogin.jsp" />
</action>
<action
path="/accessManagePage"
type="cn.edu.scut.www.ginge.action.AccessManagePageAction"
roles="administrator">
<forward name="success" path="/manage.jsp" />
<forward name="failure" path="/accessDenied.jsp" />
</action>
</action-mappings>
<controller>
<set-property property="processorClass"
value="cn.edu.scut.www.ginge.CheckRequestProcessor"/>
</controller>
<message-resources parameter="cn.edu.scut.www.ginge.ApplicationResources" />
</struts-config>
2.2Q?br> userLogin.jsp的主要内?
<html:form action="/userLogin.do">
userName : <html:text property="userName"/><html:errors property="userName"/><br/>
password : <html:password property="password"/><html:errors property="password"/><br/>
<html:submit/><html:cancel/>
2.3Q?br> successfullyLogin.jsp的主要内容：(x)
<a href="http://localhost:8099/StrutsRoles/accessManagePage.do">manage all members</a>
2.4 manage.jsp的主要内容：(x)
<h1><font color="red">q是理员管理的面</font></h1> <br>
2.5 accessDenied.jsp的主要内容：(x)
<h1><font color="red">抱歉Q你的权限不够！</font></h1>
2.6Q?br> UserLoginAction.java:
//Created by MyEclipse Struts
// XSL source (default): platform:/plugin/com.genuitec.eclipse.cross.easystruts.eclipse_3.9.210/xslt/JavaClass.xsl
package cn.edu.scut.www.ginge.action;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import cn.edu.scut.www.ginge.form.UserLoginForm;
/**
* MyEclipse Struts
* Creation date: 12-10-2005
*
* XDoclet definition:
* @struts:action path="/userLogin" name="userLoginForm" input="/form/userLogin.jsp" scope="request" validate="true"
* @struts:action-forward name="success" path="/accessDenied.jsp"
* @struts:action-forward name="failure" path="/accessDenied.jsp"
*/
public class UserLoginAction extends Action {
// --------------------------------------------------------- Instance Variables
// --------------------------------------------------------- Methods
/**
* Method execute
* @param mapping
* @param form
* @param request
* @param response
* @return ActionForward
*/
public ActionForward execute(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
UserLoginForm userLoginForm = (UserLoginForm) form;
if("ginge".equals(userLoginForm.getUserName()) && "ginge".equals(userLoginForm.getPassword()))
{
HttpSession session = request.getSession(true);
session.setAttribute("userName", userLoginForm.getUserName());
return mapping.findForward("successfullyLogin");
}
if("fantasyginge".equals(userLoginForm.getUserName()) && "fantasyginge".equals(userLoginForm.getPassword()))
{
HttpSession session = request.getSession(true);
session.setAttribute("userName", userLoginForm.getUserName());
return mapping.findForward("successfullyLogin");
}
else
return mapping.findForward("failureLogin");
}
}
2.7Q?br> AccessManagePageAction.java
//Created by MyEclipse Struts
// XSL source (default): platform:/plugin/com.genuitec.eclipse.cross.easystruts.eclipse_3.9.210/xslt/JavaClass.xsl
package cn.edu.scut.www.ginge.action;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
/**
* MyEclipse Struts
* Creation date: 12-10-2005
*
* XDoclet definition:
* @struts:action validate="true"
* @struts:action-forward name="success" path="/authorizedAccess.jsp"
* @struts:action-forward name="failure" path="/accessDenied.jsp"
*/
public class AccessManagePageAction extends Action {
// --------------------------------------------------------- Instance Variables
// --------------------------------------------------------- Methods
/**
* Method execute
* @param mapping
* @param form
* @param request
* @param response
* @return ActionForward
*/
public ActionForward execute(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
//if processRoles passed, then forward the user to the resources he has asked
return mapping.findForward("success");
}
}
2.8
q是RequestProcess process method的默认实玎ͼ(x)
public void process(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
// Wrap multipart requests with a special wrapper
request = processMultipart(request);
// Identify the path component we will use to select a mapping
String path = processPath(request, response);
if (path == null) {
return;
}
if (log.isDebugEnabled()) {
log.debug("Processing a '" + request.getMethod() +
"' for path '" + path + "'");
}
// Select a Locale for the current user if requested
processLocale(request, response);
// Set the content type and no-caching headers if requested
processContent(request, response);
processNoCache(request, response);
// General purpose preprocessing hook
if (!processPreprocess(request, response)) {
return;
}
this.processCachedMessages(request, response);
// Identify the mapping for this request
ActionMapping mapping = processMapping(request, response, path);
if (mapping == null) {
return;
}
// Check for any role required to perform this action
if (!processRoles(request, response, mapping)) {
return;
}
// Process any ActionForm bean related to this request
ActionForm form = processActionForm(request, response, mapping);
processPopulate(request, response, form, mapping);
if (!processValidate(request, response, form, mapping)) {
return;
}
// Process a forward or include specified by this mapping
if (!processForward(request, response, mapping)) {
return;
}
if (!processInclude(request, response, mapping)) {
return;
}
// Create or acquire the Action instance to process this request
Action action = processActionCreate(request, response, mapping);
if (action == null) {
return;
}
// Call the Action instance itself
ActionForward forward =
processActionPerform(request, response,
action, form, mapping);
// Process the returned ActionForward instance
processForwardConfig(request, response, forward);
}
2.9
CheckRequestProcessor 的代码：(x)
package cn.edu.scut.www.ginge;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.RequestProcessor;
public class CheckRequestProcessor extends RequestProcessor {
protected boolean processPreprocess(HttpServletRequest request,
HttpServletResponse response) {
// TODO Auto-generated method stub
HttpSession session = request.getSession(false);
// If user is trying to access login page
// then don't check
if (request.getServletPath().equals("/userLogin.do")
|| request.getServletPath().equals("/login.do"))
return true;
// Check if userName attribute is there is session.
// If so, it means user has allready logged in
if (session != null && session.getAttribute("userName") != null)
return true;
else {
try {
// If no redirect user to login Page
request.getRequestDispatcher("/form/userLogin.jsp").forward(request,
response);
} catch (Exception ex) {
}
}
return false;
}
protected boolean processRoles(HttpServletRequest request,
HttpServletResponse response, ActionMapping mapping) throws IOException,
ServletException {
// TODO Auto-generated method stub
String [] roles = mapping.getRoleNames();
if ((roles == null) || (roles.length < 1)) {
return (true);
}
HttpSession session = request.getSession(false);
String userName = null;
String actualRoles = null;
if (session != null && session.getAttribute("userName") != null)
{
userName = (String)session.getAttribute("userName");
//unidentified user
if((actualRoles = processUserActualRole(userName)) == null)
{
return false;
}
for(int i = 0; i < roles.length; i ++)
{
if (actualRoles.equalsIgnoreCase(roles[i])) {
if (log.isDebugEnabled()) {
log.debug(" User '" + request.getRemoteUser() +
"' has role '" + roles[i] + "', granting access");
}
return (true);
}
}
}
// The current user is not authorized for this action
if (log.isDebugEnabled()) {
log.debug(" User '" + request.getRemoteUser() +
"' does not have any required role, denying access");
}
//user's priviledge isn't sufficient
/*
response.sendError(
HttpServletResponse.SC_FORBIDDEN,
getInternal().getMessage("notAuthorized", mapping.getPath()));
*/
try {
// If no redirect user to login Page
request.getRequestDispatcher((mapping.findForward("failure")).getPath()).forward(request,
response);
} catch (Exception ex) {
}
return (false);
}
protected void processContent(HttpServletRequest request,
HttpServletResponse response) {
// TODO Auto-generated method stub
// Check if user is requesting ContactImageAction
// if yes then set image/gif as content type
response.setContentType("text/html;charset=gb2312");
}
protected String processUserActualRole(String userName)
{
//or other bussiness login,or access database to get the user information
if("fantasyginge".equalsIgnoreCase(userName))
{
return "administrator";
}
else if("ginge".equals(userName))
{
return "normalUser";
}
else
return null;
}
}
E序q行效果Q?br> 用用户名gingedq且讉K已设roles讉K控制的结果：(x)
抱歉Q你的权限不够！
而用fantasygingedq且讉K已设roles讉K控制的结果：(x)
q是理员管理的面
fantasyginge 2005-12-10 23:51 发表评论
]]>发表?cnJava | 发表旉: 2005q十?2? 15:48
我见q许多项目开发者实现自׃有的MVC框架。这些开发者ƈ不是因ؓ(f)惛_C同于Struts的某些功能，而是q没有意识到怎么L展Struts。通过开发自qMVC框架Q你可以掌控全局Q但同时q也意味着你必M出很大的代h(hun)Q在目计划很紧的情况下也许Ҏ(gu)׃可能实现?BR>
Struts不但功能强大也易于扩展。你可以通过三种方式来扩展Struts:
1.PlugInQ在应用启动或关闭时L行某业务逻辑Q创Z自己的PlugInc?BR>
2.RequestProcessorQ在h处理阶段一个特定点Ʋ执行某业务逻辑Q创Z自己的RequestProcessor。例如：(x)你想l承RequestProcessor来检查用L(fng)录及(qing)在执行每个请求时他是否有权限执行某个动作?BR>
3.ActionServletQ在应用启动或关闭或在请求处理阶D|执行某业务逻辑Q(h)承ActionServletcR但是必M只能在PligIn和RequestProcessor都不能满你的需求时候用?BR>
本文?x)列举一个简单的Struts应用来示范如何用以上三U方式扩展Struts。在本文末尾资源区有每种方式的可下蝲样例源代码。Struts Validation 框架?Tiles 框架是最成功两个的Struts扩展例子?BR>
我是假设读者已l熟(zhn)Struts框架q知道怎样使用它创建简单的应用。如想了(jin)解更多有关Struts的资料请参见资源区?BR>
PlugIn
Ҏ(gu)Struts文Q“PlugIn是一个须在应用启动和关闭旉被通知的模块定制资源或服务配置包”。这是_(d)你可以创Z个类Q它实现PlugIn的接口以便在应用启动和关闭时做你惌的事?BR>
假如创徏?jin)一个web应用Q其中用Hibernate做ؓ(f)持久化机Ӟ当应用一启动Q就需初始化HinernateQ这样在web应用接收到第一个请求时QHibernate已被配置完毕q待命。同时在应用关闭时要关闭Hibernate。跟着以下两步可以实现Hibernate PlugIn的需求?BR>
1.创徏一个实现PlugIn接口的类Q如下：(x)
public class HibernatePlugIn implements PlugIn{
private String configFile;
// This method will be called at application shutdown time
public void destroy() {
System.out.println("Entering HibernatePlugIn.destroy()");
//Put hibernate cleanup code here
System.out.println("Exiting HibernatePlugIn.destroy()");
}
//This method will be called at application startup time
public void init(ActionServlet actionServlet, ModuleConfig config)
throws ServletException {
System.out.println("Entering HibernatePlugIn.init()");
System.out.println("Value of init parameter " +
getConfigFile());
System.out.println("Exiting HibernatePlugIn.init()");
}
public String getConfigFile() {
return name;
}
public void setConfigFile(String string) {
configFile = string;
}
}实现PlugIn接口的类必须是实C下两个方法：(x)
init() 和destroy().。在应用启动时init()被调用，关闭destroy()被调用。Struts允许你传入初始参数给你的PlugInc；Z(jin)传入参数你必dPlugInc里为每个参数创Z个类似JavaBean形式的setterҎ(gu)。在HibernatePlugInc里Q欲传入configFile的名字而不是在应用里将它硬~码q去
2.在struts-condig.xml里面加入以下几行告知Strutsq个新的PlugIn
<struts-config>
...
<!-- Message Resources -->
<message-resources parameter=
"sample1.resources.ApplicationResources"/>
<!-- Declare your plugins -->
<plug-in className="com.sample.util.HibernatePlugIn">
<set-property property="configFile"
value="/hibernate.cfg.xml"/>
</plug-in>
</struts-config>
ClassName属性是实现PlugIn接口cȝ全名。ؓ(f)每一个初始化传入PlugIncȝ初始化参数增加一?lt;set-property>元素。在q个例子里，传入config文档的名Uͼ所以增加了(jin)一个config文路径?lt;set-property>元素?BR>
Tiles和Validator框架都是利用PlugInl初始化d配置文g。另外两个你q可以在PlugInc里做的事情是：(x)
假如应用依赖于某配置文gQ那么可以在PlugInc里(g)查其可用性，假如配置文g不可用则抛出ServletException。这导致ActionServlet不可用?BR>
PlugIn接口的init()Ҏ(gu)是你改变ModuleConfigҎ(gu)的最后机?x)，ModuleConfigҎ(gu)是描q基于Struts模型?rn)态配|信息的集合。一旦PlugIn被处理完毕，Struts׃(x)ModuleCOnfigȝh?BR>
h是如何被处理?/SPAN>
ActionServlet是Struts框架里唯一一个ServletQ它负责处理所有请求。它无论何时收到一个请求，都会(x)首先试着为现有请求找C个子应用。一旦子应用被找刎ͼ它会(x)为其生成一个RequestProcessor对象Qƈ调用传入HttpServletRequest和HttpServletResponse为参数的process()Ҏ(gu)?BR>
大部分请处理都是在RequestProcessor.process()发生的。Process()Ҏ(gu)是以模板Ҏ(gu)QTemplate MethodQ的设计模式来实现的Q其中有完成request处理的每个步骤的Ҏ(gu)Q所有这些方法都从process()Ҏ(gu)序调用。例如，L当前h的ActionFormcd(g)查当前用h否有权限执行action mapping都有几个单独的方法。这l我们提供了(jin)极大的弹性空间。Struts的RequestProcessorҎ(gu)个请求处理步骤都提供?jin)默认的实现?gu)。这意味着Q你可以重写你感兴趣的方法，而其余剩下的保留默认实现。例如，Struts默认调用request.isUserInRole()(g)查用h否有权限执行当前的ActionMappingQ但如果你需要从数据库中查找Q那么你要做的就是重写processRoles()Ҏ(gu)QƈҎ(gu)用户角色q回true ?false?BR>
首先我们看一下process()Ҏ(gu)的默认实现方式，然后我将解释RequestProcessorc里的每个默认的Ҏ(gu)Q以便你军_要修改请求处理的哪一部分?BR>
public void process(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
// Wrap multipart requests with a special wrapper
request = processMultipart(request);
// Identify the path component we will
// use to select a mapping
String path = processPath(request, response);
if (path == null) {
return;
}
if (log.isDebugEnabled()) {
log.debug("Processing a '" + request.getMethod() +
"' for path '" + path + "'");
}
// Select a Locale for the current user if requested
processLocale(request, response);
// Set the content type and no-caching headers
// if requested
processContent(request, response);
processNoCache(request, response);
// General purpose preprocessing hook
if (!processPreprocess(request, response)) {
return;
}
// Identify the mapping for this request
ActionMapping mapping =
processMapping(request, response, path);
if (mapping == null) {
return;
}
// Check for any role required to perform this action
if (!processRoles(request, response, mapping)) {
return;
}
// Process any ActionForm bean related to this request
ActionForm form =
processActionForm(request, response, mapping);
processPopulate(request, response, form, mapping);
if (!processValidate(request, response, form, mapping)) {
return;
}
// Process a forward or include specified by this mapping
if (!processForward(request, response, mapping)) {
return;
}
if (!processInclude(request, response, mapping)) {
return;
}
// Create or acquire the Action instance to
// process this request
Action action =
processActionCreate(request, response, mapping);
if (action == null) {
return;
}
// Call the Action instance itself
ActionForward forward =
processActionPerform(request, response,
action, form, mapping);
// Process the returned ActionForward instance
processForwardConfig(request, response, forward);
}
1、processMultipart(): 在这个方法中QStrutsdrequest以找出contentType是否为multipart/form-data。假如是Q则解析q将其打包成一个实现HttpServletRequest的包。当你成生一个放|数据的HTML FORMӞrequest的contentType默认是application/x-www-form-urlencoded。但是如果你的form的inputcd是FILE-type允许用户上蝲文gQ那么你必须把form的contentType改ؓ(f)multipart/form-data。如q样做，你永q不能通过HttpServletRequest的getParameter()来读取用h交的form|你必MInputStream的Ş式读取requestQ然后解析它得到倹{?BR>
2、processPath(): 在这个方法中QStruts读取request的URI以判断用来得到ActionMapping元素的\径?BR>
3、processLocale(): 在这个方法中QStruts得到当前request的LocaleQLocale假如被配|，作为org.apache.struts.action.LOCALE属性的D存入HttpSession。这个方法的附作用是HttpSession?x)被创徏。假如你不想此事发生Q可在struts-config.xml 文g里ControllerConfig的local属性设|ؓ(f)false,如下Q?BR>
<controller>
<set-property property="locale" value="false"/>
</controller>
4、processContent()Q?/B>通过调用response.setContentType()讄response的contentType。这个方法首先会(x)试着的得到配|在struts-config.xml里的contentType。默认ؓ(f)text/htmlQ重写方法如下：(x)
<controller>
<set-property property="contentType" value="text/plain"/>
</controller>
5、processNoCache()Q?/B>Strutsؓ(f)每个response的设|以下三个headerQ假如已在struts 的config.xml配|ؓ(f)no-cache?BR>
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 1);假如你想讄为no-cache headerQ在struts-config.xml中加如以下几?BR>
<controller>
<set-property property="noCache" value="true"/>
</controller>
6、processPreprocess()Q?/B>q是一个一般意义的预处理hookQ其可被子类重写。在RequestProcessor里的实现什么都没有做，Lq回true。如此方法返回false?x)中断请求处理?BR>
7、processMapping():q个Ҏ(gu)?x)利用path信息扑ֈActionMapping对象。ActionMapping对象在struts-config.xml file文g里表CZؓ(f)<action>
<action path="/newcontact" type="com.sample.NewContactAction"
name="newContactForm" scope="request">
<forward name="sucess" path="/sucessPage.do"/>
<forward name="failure" path="/failurePage.do"/>
</action>
ActionMapping元素包含?jin)如Actioncȝ名称?qing)在h中用到的ActionForm的信息，另外q有配置在当前ActionMapping的里的ActionForwards信息?BR>
8、processRoles(): Struts的web 应用安全提供?jin)一个认证机制。这是_(d)一旦用L(fng)录到容器QStruts的processRoles()Ҏ(gu)通过调用request.isUserInRole()可以(g)查他是否有权限执行给定的ActionMapping?BR> <action path="/addUser" roles="administrator"/>
假如你有一个AddUserActionQ限制只有administrator权限的用h能新d用户。你所要做的就是在AddUserAction 的action元素里添加一个gؓ(f)administrator的role属性?BR>
9、processActionForm()Q?/B>每个ActionMapping都有一个与它关联的ActionFormcRstruts在处理ActionMappingӞ他会(x)?lt;action>里name属性找到相关的ActionFormcȝ倹{?BR>
<form-bean name="newContactForm"
type="org.apache.struts.action.DynaActionForm">
<form-property name="firstName"
type="java.lang.String"/>
<form-property name="lastName"
type="java.lang.String"/>
</form-bean>
在这个例子里Q首先会(x)(g)查org.apache.struts.action.DynaActionFormcȝ对象是否在request 范围内。如是，则用它Q否则创Z个新的对象ƈ在request范围内设|它?BR>
10、processPopulate():Q?/B>在这个方法里QStruts匹配的request parameters值填入ActionFormcȝ实例变量中?BR>
11、processValidate()Q?/B>Struts调用ActionForm的validate()Ҏ(gu)。假如validate()q回ActionErrorsQStruts用戯{到由<action>里的input属性标C的面?BR>
12、processForward() and processInclude()Q?/B>在这两个Ҏ(gu)里，Struts(g)?lt;action>元素的forward和include属性的|假如有配|，则把forward和include h攑֜配置的页面内?BR>
<action forward="/Login.jsp" path="/loginInput"/>
<action include="/Login.jsp" path="/loginInput"/>
你可以从他们的名字看出其不同之处。processForward()调用RequestDispatcher.forward(),QprocessInclude()调用RequestDispatcher.include()。假如你同时配置?jin)orward 和include 属性，StrutsM(x)调用forwardQ因为forward,是首先被处理的?BR>
13、processActionCreate()Q?/B>q个Ҏ(gu)?lt;action>的type属性得到ActioncdQƈ创徏q回它的实例。在q里例子中struts创Z个com.sample.NewContactActioncȝ实例?BR>
14、processActionPerform()Q?/B>q个Ҏ(gu)调用Action cȝexecute()Ҏ(gu)Q其中有你写入的业务逻辑?BR>
15、processForwardConfig()Q?/B>Actioncȝexecute()会(x)q回一个ActionForwardcd的对象，指出哪一面展C给用户。因此Strutsؓ(f)q个面创徏RequestDispatchetQ然后再调用RequestDispatcher.forward()Ҏ(gu)?BR>
以上列出的方法解释了(jin)RequestProcessor在请求处理的每步默认实现?qing)各个步骤执行的序。正如你所见，RequestProcessor很有Ҏ(gu)，它允怽通过讄<controller>里的属性来配置它。例如，假如你的应用生成XML内容而不是HTMLQ你可以通过讄controller的某个属性来通知Struts?BR>
创徏你自qRequestProcessor
从以上内Ҏ(gu)们已l明白了(jin)RequestProcessor的默认实现是怎样工作的，现在我将通过创徏你自qRequestProcessor.展示一个怎样自定义RequestProcessor的例子。ؓ(f)?jin)演C创Z个自定义RequestProcessorQ我修改例子实C下连个业务需求：(x)
我们要创Z个ContactImageActionc，它将生成images而不是一般的HTMl面
在处理这个请求之前，通过(g)查session里的userName属性来认用户是否d。假如此属性没有被扑ֈQ则用戯{到登录页面?BR>
分两步来实现以上q个业务需求?BR>创徏你自qCustomRequestProcessorc，它将l承RequestProcessorc，如下Q?BR>
public class CustomRequestProcessor
extends RequestProcessor {
protected boolean processPreprocess (
HttpServletRequest request,
HttpServletResponse response) {
HttpSession session = request.getSession(false);
//If user is trying to access login page
// then don't check
if( request.getServletPath().equals("/loginInput.do")
|| request.getServletPath().equals("/login.do") )
return true;
//Check if userName attribute is there is session.
//If so, it means user has allready logged in
if( session != null &&
session.getAttribute("userName") != null)
return true;
else{
try{
//If no redirect user to login Page
request.getRequestDispatcher
("/Login.jsp").forward(request,response);
}catch(Exception ex){
}
}
return false;
}
protected void processContent(HttpServletRequest request,
HttpServletResponse response) {
//Check if user is requesting ContactImageAction
// if yes then set image/gif as content type
if( request.getServletPath().equals("/contactimage.do")){
response.setContentType("image/gif");
return;
}
super.processContent(request, response);
}
}
在CustomRequestProcessor cȝprocessPreprocessҎ(gu)里，(g)查session的userName属性，假如没有扑ֈQ将用户转到d面?BR>
对于产生images作ؓ(f)ContactImageActioncȝ输出Q必要重写processContentҎ(gu)。首先检查其request是否h/contactimage路径Q如是则讄contentType为image/gifQ否则ؓ(f)text/html?BR>
加入以下几行代码到sruts-config.xml文g里的<action-mapping>后面Q告知Struts QCustomRequestProcessor应该被用作RequestProcessorc?BR>
<controller>
<set-property property="processorClass"
value="com.sample.util.CustomRequestProcessor"/>
</controller>
h意，假如你只是很生成contentType不是text/html输出的Actionc，重写processContent()没有问题。如不是q种情况Q你必须创徏一个Struts子系l来处理生成image Action的请求ƈ讄contentType为image/gif
Title框架使用自己的RequestProcessor来装饰Struts生成的输出?BR>
ActionServlet
假如你仔l研IStruts web应用的web.xml文gQ它看上dq样Q?BR>
<web-app >
<servlet>
<servlet-name>action=</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<!-- All your init-params go here-->
</servlet>
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
</web-app >
q就是说QActionServlet负责处理所有发向Struts的请求。你可以创徏ActionServlet的一个子c，假如你想在应用启动和关闭时或每次h时做某些事情。但是你必须在(h)承ActionServletcd创徏PlugIn ?RequestProcessor。在Servlet 1.1前，Title框架是基于(h)承ActionServletcL装饰一个生成的response。但?.1开始，׃用TilesRequestProcessorcR?BR>
l论
开发你自己的MVC模型是一个很大的军_(j)——你必须考虑开发和l护代码的时间和资源。Struts是一个功能强大且E_的框Ӟ你可以修改它以其满你大部分的业务需求?BR>
另一斚wQ也不要L地决定扩展Struts。假如你在RequestProcessor里放入一些低效率的代码，q些代码在每次h时执行ƈ大大地降低整个应用的效率。当然L创徏你自qMVC框架比扩展Struts更好的情c(din)?BR>
fantasyginge 2005-12-10 12:12 发表评论
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