參考鏈接:html
http://blog.csdn.net/laner0515/article/details/27692673/java
http://www.cnblogs.com/sobne/articles/5443114.htmlweb
1、Struts2原理spring
Struts設計的第一目標就是使MVC模式應用於web程序設計。在這兒MVC模式的好處就不在提了。apache
Struts2有兩方面的技術優點,一是全部的Struts2應用程序都是基於client/server HTTP交換協議,The Java Servlet API揭示了java Servlet只是Java API的一個很小子集,這樣咱們能夠在業務邏輯部分使用功能強大的Java語言進行程序設計。json
二是提供了對MVC的一個清晰的實現,這一實現包含了不少參與對因此請求進行處理的關鍵組件,如:攔截器、OGNL表達式語言、堆棧。設計模式
由於struts2有這樣目標,而且有這樣的優點,因此,這是咱們學習struts2的理由,下面,咱們在深刻剖析一下struts的工做原理。api
Suruts2的工做原理能夠用下面這張圖來描述,下面咱們分步驟介紹一下每一步的核心內容安全
一個請求在Struts2框架中的處理大概分爲如下幾個步驟 session
一、客戶端初始化一個指向Servlet容器(例如Tomcat)的請求
二、這個請求通過一系列的過濾器(Filter)(這些過濾器中有一個叫作ActionContextCleanUp的可選過濾器,這個過濾器對於Struts2和其餘框架的集成頗有幫助,例如:SiteMesh Plugin)
三、接着FilterDispatcher被調用,FilterDispatcher詢問ActionMapper來決定這個請是否須要調用某個Action
FilterDispatcher是控制器的核心,就是mvc中c控制層的核心。下面粗略的分析下我理解的FilterDispatcher工做流程和原理:FilterDispatcher進行初始化並啓用核心doFilter
1 public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException ...{ 2 HttpServletRequest request = (HttpServletRequest) req; 3 HttpServletResponse response = (HttpServletResponse) res; 4 ServletContext servletContext = filterConfig.getServletContext(); 5 // 在這裏處理了HttpServletRequest和HttpServletResponse。 6 DispatcherUtils du = DispatcherUtils.getInstance(); 7 du.prepare(request, response);//正如這個方法名字同樣進行locale、encoding以及特殊request parameters設置 8 try ...{ 9 request = du.wrapRequest(request, servletContext);//對request進行包裝 10 } catch (IOException e) ...{ 11 String message = "Could not wrap servlet request with MultipartRequestWrapper!"; 12 LOG.error(message, e); 13 throw new ServletException(message, e); 14 } 15 ActionMapperIF mapper = ActionMapperFactory.getMapper();//獲得action的mapper 16 ActionMapping mapping = mapper.getMapping(request);// 獲得action 的 mapping 17 if (mapping == null) ...{ 18 // there is no action in this request, should we look for a static resource? 19 String resourcePath = RequestUtils.getServletPath(request); 20 if ("".equals(resourcePath) && null != request.getPathInfo()) ...{ 21 resourcePath = request.getPathInfo(); 22 } 23 if ("true".equals(Configuration.get(WebWorkConstants.WEBWORK_SERVE_STATIC_CONTENT)) 24 && resourcePath.startsWith("/webwork")) ...{ 25 String name = resourcePath.substring("/webwork".length()); 26 findStaticResource(name, response); 27 } else ...{ 28 // this is a normal request, let it pass through 29 chain.doFilter(request, response); 30 } 31 // WW did its job here 32 return; 33 } 34 Object o = null; 35 try ...{ 36 //setupContainer(request); 37 o = beforeActionInvocation(request, servletContext); 38 //整個框架最最核心的方法,下面分析 39 du.serviceAction(request, response, servletContext, mapping); 40 } finally ...{ 41 afterActionInvocation(request, servletContext, o); 42 ActionContext.setContext(null); 43 } 44 } 45 du.serviceAction(request, response, servletContext, mapping); 46 //這個方法詢問ActionMapper是否須要調用某個Action來處理這個(request)請求,若是ActionMapper決定須要調用某個Action,FilterDispatcher把請求的處理交給ActionProxy 47 48 public void serviceAction(HttpServletRequest request, HttpServletResponse response, String namespace, String actionName, Map requestMap, Map parameterMap, Map sessionMap, Map applicationMap) ...{ 49 HashMap extraContext = createContextMap(requestMap, parameterMap, sessionMap, applicationMap, request, response, getServletConfig()); //實例化Map請求 ,詢問ActionMapper是否須要調用某個Action來處理這個(request)請求 50 extraContext.put(SERVLET_DISPATCHER, this); 51 OgnlValueStack stack = (OgnlValueStack) request.getAttribute(ServletActionContext.WEBWORK_VALUESTACK_KEY); 52 if (stack != null) ...{ 53 extraContext.put(ActionContext.VALUE_STACK,new OgnlValueStack(stack)); 54 } 55 try ...{ 56 ActionProxy proxy = ActionProxyFactory.getFactory().createActionProxy(namespace, actionName, extraContext); 57 //這裏actionName是經過兩道getActionName解析出來的, FilterDispatcher把請求的處理交給ActionProxy,下面是ServletDispatcher的 TODO: 58 request.setAttribute(ServletActionContext.WEBWORK_VALUESTACK_KEY, proxy.getInvocation().getStack()); 59 proxy.execute(); 60 //經過代理模式執行ActionProxy 61 if (stack != null)...{ 62 request.setAttribute(ServletActionContext.WEBWORK_VALUESTACK_KEY,stack); 63 } 64 } catch (ConfigurationException e) ...{ 65 log.error("Could not find action", e); 66 sendError(request, response, HttpServletResponse.SC_NOT_FOUND, e); 67 } catch (Exception e) ...{ 68 log.error("Could not execute action", e); 69 sendError(request, response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e); 70 } 71 }
四、若是ActionMapper決定須要調用某個Action,FilterDispatcher把請求的處理交給ActionProxy
五、ActionProxy經過ConfigurationManager詢問框架的配置文件,找到須要調用的Action類 ,這裏,咱們通常是從struts.xml配置中讀取。
六、ActionProxy建立一個ActionInvocation的實例。
七、ActionInvocation實例使用命名模式來調用,在調用Action的過程先後,涉及到相關攔截器(Intercepter)的調用。
下面咱們來看看ActionInvocation是如何工做的:
ActionInvocation是Xworks 中Action 調度的核心。而對Interceptor 的調度,也正是由ActionInvocation負責。ActionInvocation 是一個接口,而DefaultActionInvocation 則是Webwork 對ActionInvocation的默認實現。
Interceptor的調度流程大體以下:
1.ActionInvocation初始化時,根據配置,加載Action相關的全部Interceptor。
2. 經過ActionInvocation.invoke方法調用Action實現時,執行Interceptor。
Interceptor將不少功能從咱們的Action中獨立出來,大量減小了咱們Action的代碼,獨立出來的行爲具備很好的重用性。XWork、WebWork的許多功能都是有Interceptor實現,能夠在配置文件中組裝Action用到的Interceptor,它會按照你指定的順序,在Action執行先後運行。
這裏,咱們簡單的介紹一下Interceptor
在struts2中自帶了不少攔截器,在struts2-core-2.1.6.jar這個包下的struts-default.xml中咱們能夠發現:
1 <interceptors> 2 <interceptor name="alias"class="com.opensymphony.xwork2.interceptor.AliasInterceptor"/> 3 <interceptor name="autowiring"class="com.opensymphony.xwork2.spring.interceptor.ActionAutowiringInterceptor"/> 4 <interceptor name="chain"class="com.opensymphony.xwork2.interceptor.ChainingInterceptor"/> 5 <interceptor name="conversionError"class="org.apache.struts2.interceptor.StrutsConversionErrorInterceptor"/> 6 <interceptor name="clearSession"class="org.apache.struts2.interceptor.ClearSessionInterceptor"/> 7 <interceptor name="createSession"class="org.apache.struts2.interceptor.CreateSessionInterceptor"/> 8 <interceptor name="debugging"class="org.apache.struts2.interceptor.debugging.DebuggingInterceptor"/> 9 <interceptor name="externalRef"class="com.opensymphony.xwork2.interceptor.ExternalReferencesInterceptor"/> 10 <interceptor name="execAndWait"class="org.apache.struts2.interceptor.ExecuteAndWaitInterceptor"/> 11 <interceptor name="exception"class="com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor"/> 12 <interceptor name="fileUpload"class="org.apache.struts2.interceptor.FileUploadInterceptor"/> 13 <interceptor name="i18n"class="com.opensymphony.xwork2.interceptor.I18nInterceptor"/> 14 <interceptor name="logger"class="com.opensymphony.xwork2.interceptor.LoggingInterceptor"/> 15 <interceptor name="modelDriven"class="com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor"/> 16 <interceptor name="scopedModelDriven"class="com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor"/> 17 <interceptor name="params"class="com.opensymphony.xwork2.interceptor.ParametersInterceptor"/> 18 <interceptor name="actionMappingParams"class="org.apache.struts2.interceptor.ActionMappingParametersInteceptor"/> 19 <interceptor name="prepare"class="com.opensymphony.xwork2.interceptor.PrepareInterceptor"/> 20 <interceptor name="staticParams"class="com.opensymphony.xwork2.interceptor.StaticParametersInterceptor"/> 21 <interceptor name="scope"class="org.apache.struts2.interceptor.ScopeInterceptor"/> 22 <interceptor name="servletConfig"class="org.apache.struts2.interceptor.ServletConfigInterceptor"/> 23 <interceptor name="sessionAutowiring"class="org.apache.struts2.spring.interceptor.SessionContextAutowiringInterceptor"/> 24 <interceptor name="timer"class="com.opensymphony.xwork2.interceptor.TimerInterceptor"/> 25 <interceptor name="token"class="org.apache.struts2.interceptor.TokenInterceptor"/> 26 <interceptor name="tokenSession"class="org.apache.struts2.interceptor.TokenSessionStoreInterceptor"/> 27 <interceptor name="validation"class="org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor"/> 28 <interceptor name="workflow"class="com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor"/> 29 <interceptor name="store"class="org.apache.struts2.interceptor.MessageStoreInterceptor"/> 30 <interceptor name="checkbox"class="org.apache.struts2.interceptor.CheckboxInterceptor"/> 31 <interceptor name="profiling"class="org.apache.struts2.interceptor.ProfilingActivationInterceptor"/> 32 <interceptor name="roles"class="org.apache.struts2.interceptor.RolesInterceptor"/> 33 <interceptor name="jsonValidation"class="org.apache.struts2.interceptor.validation.JSONValidationInterceptor"/> 34 <interceptornameinterceptorname="annotationWorkflow"class="com.opensymphony.xwork2.interceptor.annotations.AnnotationWorkflowInterceptor"/>
對於sturts2自帶的攔截器,使用起來就相對比較方便了,咱們只須要在struts.xml的action標籤中加入<interceptor-ref name=" logger " />而且struts.xml擴展struts-default,就可使用,
若是是要自定義攔截器,首先須要寫一個攔截器的類:
1 package ceshi; 2 import com.opensymphony.xwork2.ActionInvocation; 3 import com.opensymphony.xwork2.interceptor.AbstractInterceptor; 4 5 publicclassAuthorizationInterceptor extends AbstractInterceptor { 6 7 @Override 8 public Stringintercept(ActionInvocation ai)throws Exception { 9 10 System.out.println("abc"); 11 return ai.invoke(); 12 13 } 14 15 }
而且在struts.xml中進行配置
1 <!DOCTYPEstruts PUBLIC 2 "-//Apache SoftwareFoundation//DTD Struts Configuration 2.0//EN" 3 "http://struts.apache.org/dtds/struts-2.0.dtd"> 4 5 6 <struts> 7 <package name="test"extends="struts-default"> 8 <interceptors> 9 <interceptor name="abc"class ="ceshi.AuthorizationInterceptor"/> 10 </interceptors> 11 <action name="TestLogger"class="vaannila.TestLoggerAction"> 12 <interceptor-refnameinterceptor-refname="abc"/> 13 <result name="success">/success.jsp</result> 14 </action> 15 </package> 16 </struts>
八、一旦Action執行完畢,ActionInvocation負責根據struts.xml中的配置找到對應的返回結果。返回結果一般是(但不老是,也多是另外的一個Action鏈)一個須要被表示的JSP或者FreeMarker的模版。在表示的過程當中可使用Struts2 框架中繼承的標籤。在這個過程當中須要涉及到ActionMapper
在上述過程當中全部的對象(Action,Results,Interceptors,等)都是經過ObjectFactory來建立的。
struts2相對於struts1來講簡單了不少,而且功能強大了不少,咱們能夠從幾個方面來看:
從體系結構來看:struts2大量使用攔截器來出來請求,從而容許與業務邏輯控制器 與 servlet-api分離,避免了侵入性;而struts1.x在action中明顯的侵入了servlet-api.
從線程安全分析:struts2.x是線程安全的,每個對象產生一個實例,避免了線程安全問題;而struts1.x在action中屬於單線程。
性能方面:struts2.x測試能夠脫離web容器,而struts1.x依賴servlet-api,測試須要依賴web容器。
請求參數封裝對比:struts2.x使用ModelDriven模式,這樣咱們 直接 封裝model對象,無須要繼承任何struts2的基類,避免了侵入性。
標籤的優點:標籤庫幾乎能夠徹底替代JSTL的標籤庫,而且 struts2.x支持強大的ognl表達式。
固然,struts2和struts1相比,在 文件上傳,數據校驗 等方面也 方便了好多。在這就不詳談了。
一個比較優秀的框架能夠幫着咱們更高效,穩定的開發合格的產品,不過咱們也不要依賴框架,咱們只要理解了思想,設計模式,咱們能夠本身擴展功能,否則 就要 永遠讓別人牽着走了!
Java Struts2簡單入門實例和登陸實例
1 jsp出發action
2 struts2攔截請求,調用後臺action
3 action返回結果,由不一樣的jsp展示數據
項目結構
src struts.xml com hellostruts2 action HelloStrutsAction.java LoginAction.java model HelloMessage.java WebContent HelloStruts.jsp index.jsp login error.jsp login.jsp success.jsp WEB-INF web.xml classes logging.properties mess.properties mess_zh_CN.properties lib commons-fileupload-1.3.1.jar commons-io-2.2.jar commons-lang-2.4.jar commons-lang3-3.2.jar commons-logging-1.1.3.jar freemarker-2.3.22.jar javassist-3.11.0.GA.jar ognl-3.0.14.jar struts2-core-2.3.28.1.jar xwork-core-2.3.28.1.jar
Web.xml
<?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_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>Struts 2</display-name> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <filter> <filter-name>struts2CleanupFilter</filter-name> <filter-class>org.apache.struts2.dispatcher.ActionContextCleanUp</filter-class> </filter> <filter> <filter-name>struts2Filter</filter-name> <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class> </filter> <filter-mapping> <filter-name>struts2CleanupFilter</filter-name> <url-pattern>/*</url-pattern> <dispatcher>REQUEST</dispatcher> <dispatcher>FORWARD</dispatcher> </filter-mapping> <filter-mapping> <filter-name>struts2Filter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
Struts.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE struts PUBLIC 3 "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" 4 "http://struts.apache.org/dtds/struts-2.0.dtd"> 5 <struts> 6 <constant name="struts.devMode" value="true" /> 7 8 <constant name="struts.custom.i18n.resources" value="mess"/> 9 <constant name="struts.i18n.encoding" value="utf-8"/> 10 11 12 <package name="hellostruts" extends="struts-default"> 13 <action name="index"> 14 <result >/index.jsp</result> 15 </action> 16 <action name="hello" class="com.hellostruts2.action.HelloStrutsAction" method="execute"> 17 <result name="success">/HelloStruts.jsp</result> 18 </action> 19 </package> 20 <package name="loginstruts" extends="struts-default"> 21 <action name="login" class="com.hellostruts2.action.LoginAction" method="execute"> 22 <result name="input">/login/login.jsp</result> 23 <result name="success">/login/success.jsp</result> 24 <result name="error">/login/error.jsp</result> 25 </action> 26 </package> 27 28 </struts> 29 <!-- 30 <struts> 31 <include file="my-struts1.xml"/> 32 <include file="my-struts2.xml"/> 33 </struts> 34 -->
logging.properties
org.apache.catalina.core.ContainerBase.[Catalina].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].handlers = \java.util.logging.ConsoleHandler
mess.properties
loginPage=loginPage errorPage=errorPage successPage=succPage errorTip=sorry\uFF0C login failed successTip=welcome{0},login success user=username pass=password login=login
mess_zh_CN.properties
loginPage=登錄界面 errorPage=失敗界面 successPage=成功界面 errorTip=對不起,您不能登陸! successTip=歡迎,{0},您已經登陸! user=用戶名 pass=密 碼 login=登錄
入門實例:
HelloMessage.java
1 package com.hellostruts2.model; 2 3 public class HelloMessage { 4 private String message; 5 public HelloMessage(){ 6 setMessage("Hello struts2 model."); 7 } 8 public String getMessage() { 9 return message; 10 } 11 12 public void setMessage(String message) { 13 this.message = message; 14 } 15 }
HelloStrutsAction.java
1 package com.hellostruts2.action; 2 3 import com.hellostruts2.model.HelloMessage; 4 5 public class HelloStrutsAction { 6 7 private String name; 8 private HelloMessage helloMessage; 9 public String execute() throws Exception{ 10 helloMessage=new HelloMessage(); 11 helloMessage.setMessage("Hello struts model."); 12 return "success"; 13 } 14 public String getName(){ 15 return name; 16 } 17 public void setName(String name){ 18 this.name=name; 19 } 20 21 public HelloMessage getMessage(){ 22 return helloMessage; 23 } 24 public void setMessage(HelloMessage helloMessage){ 25 this.helloMessage=helloMessage; 26 } 27 }
index.jsp
<%@ 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>Hello Struts2 Form</title> </head> <body> <h1>Hello Struts2 Form</h1> <form action="hello"> <label for="name">Please enter your name</label><br/> <input type="text" name="name"/> <input type="submit" value="Say Hello"/> <p><a href="<s:url action='hello'/>">Hello Struts Model</a></p> </form> </body> </html>
HelloStruts.jsp
1 <%@ page language="java" contentType="text/html; charset=ISO-8859-1" 2 pageEncoding="ISO-8859-1"%> 3 <%@ taglib prefix="s" uri="/struts-tags" %> 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 5 <html> 6 <head> 7 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 8 <title>Hello Struts2</title> 9 </head> 10 <body> 11 <s:debug></s:debug> 12 Hello Struts2, <s:property value="name"/> 13 <br/> 14 Hello Model, <s:property value="message.message"></s:property> 15 ${message.message} 16 </body> 17 </html>
登陸實例:
當login.jsp觸發action時,就會向後擡發送login.action的請求,這個請求被後臺攔截,交給struts.xml中配置的action處理。
LoginAction.java
1 package com.hellostruts2.action; 2 3 import com.opensymphony.xwork2.ActionContext; 4 import com.opensymphony.xwork2.ActionSupport; 5 6 public class LoginAction extends ActionSupport { 7 private static final long serialVersionUID = 1L; 8 private String username; 9 private String password; 10 public String getUsername() { 11 return username; 12 } 13 public void setUsername(String username) { 14 this.username = username; 15 } 16 public String getPassword() { 17 return password; 18 } 19 public void setPassword(String password) { 20 this.password = password; 21 } 22 public String execute() throws Exception{ 23 if(getUsername().equals("test") && getPassword().equals("test")){ 24 ActionContext.getContext().getSession().put("user", getUsername()); 25 return SUCCESS; 26 }else{ 27 return ERROR; 28 } 29 } 30 public void validate(){ 31 if(username ==null || username.trim().equals("")){ 32 addFieldError("username", "user name is required"); 33 } 34 if(password.length()<3){ 35 addFieldError("password", "password must be more than 3"); 36 } 37 } 38 }
login.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <%@taglib prefix="s" uri="/struts-tags" %> 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 5 <html> 6 <head> 7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 8 <title><s:text name="loginPage"/></title> 9 </head> 10 <body> 11 <s:form action="login"> 12 <s:textfield name="username" key="user"></s:textfield> 13 <s:textfield name="password" key="pass"></s:textfield> 14 <s:submit key="login"></s:submit> 15 </s:form> 16 </body> 17 </html>
success.jsp
1 <%@ page language="java" contentType="text/html; charset=utf-8" 2 pageEncoding="utf-8"%> 3 <%@taglib prefix="s" uri="/struts-tags" %> 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 5 <html> 6 <head> 7 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 8 <title><s:text name="successPage"></s:text></title> 9 </head> 10 <body> 11 <s:text name="successTip"> 12 <s:param>${sessionScope.user}</s:param> 13 </s:text> 14 </body> 15 </html>
error.jsp
1 <%@ page language="java" contentType="text/html; charset=utf-8" 2 pageEncoding="utf-8"%> 3 <%@taglib prefix="s" uri="/struts-tags" %> 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 5 <html> 6 <head> 7 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 8 <title><s:text name="errorPage"></s:text></title> 9 </head> 10 <body> 11 <s:text name="errorTip"></s:text> 12 </body> 13 </html>
library下載:http://struts.apache.org/download.cgi