Posted on 2010-03-29 23:17
Gavin.lee 閱讀(499)
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SSH2 --Struts2
一、攔截器定義
攔截器，在AOP（Aspect-Oriented Programming）中用于在某個方法或字段被訪問之前，進行攔截然后在之前或之后加入某些操作。攔截是AOP的一種實現策略。
在Webwork的中文文檔的解釋為——攔截器是動態攔截Action調用的對象。它提供了一種機制可以使開發者可以定義在一個action執行的前后執行的代碼，也可以在一個action執行前阻止其執行。同時也是提供了一種可以提取action中可重用的部分的方式。
談到攔截器，還有一個詞大家應該知道——攔截器鏈（Interceptor Chain，在Struts 2中稱為攔截器棧Interceptor Stack）。攔截器鏈就是將攔截器按一定的順序聯結成一條鏈。在訪問被攔截的方法或字段時，攔截器鏈中的攔截器就會按其之前定義的順序被調用。
二、攔截器的流程 訪問： http://localhost:8080/interceptor1/test_interceptor.action
1.攔截器的觸發頁面
<%
@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";
%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<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="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<s:form action="test_interceptor">
<s:textfield name="username" label="username"></s:textfield>
<s:submit name="submit"></s:submit>
</s:form>
</body>
</html>
2.Struts2配置文件，攔截器的映射
<?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>
<package name="interceptor1" extends="struts-default">
<!-- 定義攔截器 -->
<interceptors>
<interceptor name="myInterceptor" class="cn.edu.hdu.interceptor.MyInterceptor"></interceptor>
</interceptors>
<!-- 配置action -->
<action name="test_interceptor" class="cn.edu.hdu.action.Test_InterceptorAction">
<result name="success">/success.jsp</result>
<result name="input">/test.jsp</result>
<!-- 將聲明好的攔截器插入action中 -->
<interceptor-ref name="myInterceptor" />
<interceptor-ref name="defaultStack" />
</action>
</package>
</struts>
3.攔截器MyInterceptor
package cn.edu.hdu.interceptor;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;
/** *//**
* 自定義攔截器
* @author gavin
* @date 2010-3-29
*/
public class MyInterceptor implements Interceptor {
/** *//**
*
*/
private static final long serialVersionUID = -4855835386612768133L;
public void destroy() {
System.out.println("destroy");
}
public void init() {
System.out.println("攔截器已經被加載");
}
public String intercept(ActionInvocation invocation) throws Exception {
System.out.println("調用intercept方法");
// invocation.invoke（）方法檢查是否還有攔截器 有的話繼續調用余下的攔截器 沒有了 執行action的業務邏輯
String result = invocation.invoke();
return result;
}
}
4.通過攔截器后進入Action
package cn.edu.hdu.action;
import com.opensymphony.xwork2.ActionSupport;
public class Test_InterceptorAction extends ActionSupport {
/** *//**
*
*/
private static final long serialVersionUID = 5138320466369666402L;
private String username;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String execute() throws Exception {
return SUCCESS;
}
public String test() throws Exception {
System.out.println("此時所有攔截器完畢，已經調用了action中的test方法");
return SUCCESS;
}
}
5.通過Action處理后的視圖頁面
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'success.jsp' starting page</title>
<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="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
去看看控制臺吧
</body>
</html>
三、Struts2默認的攔截器
<!--struts2中攔截器的定義-->
<interceptors>
<!--實現在不同請求中相似參數別名的準換-->
<interceptor name="alias" class="com.opensymphony.xwork2.interceptor.AliasInterceptor"/>
<!--與Spring整合時自動裝配的攔截器-->
<interceptor name="autowiring" class="com.opensymphony.xwork2.spring.interceptor.ActionAutowiringInterceptor"/>
<!--構建一個action鏈，使當前action可以訪問前一個action，與<result-type="chain" />配合使用-->
<interceptor name="chain" class="com.opensymphony.xwork2.interceptor.ChainingInterceptor"/>
<!--負責類型轉換的攔截器-->
<interceptor name="conversionError" class="org.apache.struts2.interceptor.StrutsConversionErrorInterceptor"/>
<!--使用配置的name,value來是指cookies -->
<interceptor name="cookie" class="org.apache.struts2.interceptor.CookieInterceptor"/>
<!--負責創建httpSession-->
<interceptor name="createSession" class="org.apache.struts2.interceptor.CreateSessionInterceptor" />
<!--輸出調試信息-->
<interceptor name="debugging" class="org.apache.struts2.interceptor.debugging.DebuggingInterceptor" />
<!--擴展引用-->
<interceptor name="externalRef" class="com.opensymphony.xwork2.interceptor.ExternalReferencesInterceptor"/>
<!--后臺執行action負責發送等待畫面給用戶-->
<interceptor name="execAndWait" class="org.apache.struts2.interceptor.ExecuteAndWaitInterceptor"/>
<!--異常處理-->
<interceptor name="exception" class="com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor"/>
<!--文件上傳，解析表單域的內容-->
<interceptor name="fileUpload" class="org.apache.struts2.interceptor.FileUploadInterceptor"/>
<!--支持國際化-->
<interceptor name="i18n" class="com.opensymphony.xwork2.interceptor.I18nInterceptor"/>
<!--日志記錄-->
<interceptor name="logger" class="com.opensymphony.xwork2.interceptor.LoggingInterceptor"/>
<!--模型攔截器，當action實現了ModelDriven接口時，負責把getModel的結果放入valueStack中-->
<interceptor name="modelDriven" class="com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor"/>
<!--有生命周期的ModelDriven-->
<interceptor name="scopedModelDriven" class="com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor"/>
<!--負責解析請求中的參數，并賦值給action中對應的屬性-->
<interceptor name="params" class="com.opensymphony.xwork2.interceptor.ParametersInterceptor"/>
<!--實現該Preparable接口的action，會調用攔截器的prepare方法-->
<interceptor name="prepare" class="com.opensymphony.xwork2.interceptor.PrepareInterceptor"/>
<!--負責將action 標簽下的param參數值傳遞給action實例-->
<interceptor name="staticParams" class="com.opensymphony.xwork2.interceptor.StaticParametersInterceptor"/>
<!--范圍轉換-->
<interceptor name="scope" class="org.apache.struts2.interceptor.ScopeInterceptor"/>
<!--用于訪問Servlet API-->
<interceptor name="servletConfig" class="org.apache.struts2.interceptor.ServletConfigInterceptor"/>
<interceptor name="sessionAutowiring" class="org.apache.struts2.spring.interceptor.SessionContextAutowiringInterceptor"/>
<!--輸出action執行時間-->
<interceptor name="timer" class="com.opensymphony.xwork2.interceptor.TimerInterceptor"/>
<!--防止表單重復提交-->
<interceptor name="token" class="org.apache.struts2.interceptor.TokenInterceptor"/>
<!--與token攔截器相似，只是把token保存到HttpSession-->
<interceptor name="tokenSession" class="org.apache.struts2.interceptor.TokenSessionStoreInterceptor"/>
<!--負責表單字段的驗證 *-validation.xml-->
<interceptor name="validation" class="org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor"/>
<!--負責執行action的validate()-->
<interceptor name="workflow" class="com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor"/>
<!--存儲和重新獲取Action 消息/錯誤/字段錯誤為Action，實現ValidationAware接口到seesion-->
<interceptor name="store" class="org.apache.struts2.interceptor.MessageStoreInterceptor" />
<!--添加自動checkbox處理代碼,這樣檢探測checkbox和添加它作為一個參數使用默認值(通常’false’).使用一個指定名字隱藏字段探測沒提交的checkbox-->
<interceptor name="checkbox" class="org.apache.struts2.interceptor.CheckboxInterceptor" />
<interceptor name="profiling" class="org.apache.struts2.interceptor.ProfilingActivationInterceptor" />
<!--JAAS服務攔截器-->
<interceptor name="roles" class="org.apache.struts2.interceptor.RolesInterceptor" />
<!-- 一個基本的攔截器棧 -->
<interceptor-stack name="basicStack">
<interceptor-ref name="exception"/>
<interceptor-ref name="servletConfig"/>
<interceptor-ref name="prepare"/>
<interceptor-ref name="checkbox"/>
<interceptor-ref name="params"/>
<interceptor-ref name="conversionError"/>
</interceptor-stack>
<!-- 簡單的validtion和webflow棧 -->
<interceptor-stack name="validationWorkflowStack">
<interceptor-ref name="basicStack"/>
<interceptor-ref name="validation"/>
<interceptor-ref name="workflow"/>
</interceptor-stack>
<!-- 文件上傳的攔截器棧 -->
<interceptor-stack name="fileUploadStack">
<interceptor-ref name="fileUpload"/>
<interceptor-ref name="basicStack"/>
</interceptor-stack>
<!-- model-driven 棧 -->
<interceptor-stack name="modelDrivenStack">
<interceptor-ref name="modelDriven"/>
<interceptor-ref name="basicStack"/>
</interceptor-stack>
<!-- action鏈的攔截器棧 -->
<interceptor-stack name="chainStack">
<interceptor-ref name="chain"/>
<interceptor-ref name="basicStack"/>
</interceptor-stack>
<!-- i18n 攔截器棧 -->
<interceptor-stack name="i18nStack">
<interceptor-ref name="i18n"/>
<interceptor-ref name="basicStack"/>
</interceptor-stack>
<!-- 結合preparable和ModenDriven攔截器-->
<interceptor-stack name="paramsPrepareParamsStack">
<interceptor-ref name="exception"/>
<interceptor-ref name="alias"/>
<interceptor-ref name="params"/>
<interceptor-ref name="servletConfig"/>
<interceptor-ref name="prepare"/>
<interceptor-ref name="i18n"/>
<interceptor-ref name="chain"/>
<interceptor-ref name="modelDriven"/>
<interceptor-ref name="fileUpload"/>
<interceptor-ref name="checkbox"/>
<interceptor-ref name="staticParams"/>
<interceptor-ref name="params"/>
<interceptor-ref name="conversionError"/>
<interceptor-ref name="validation">
<param name="excludeMethods">input,back,cancel</param>
</interceptor-ref>
<interceptor-ref name="workflow">
<param name="excludeMethods">input,back,cancel</param>
</interceptor-ref>
</interceptor-stack>
<!--定義默認的攔截器棧 -->
<interceptor-stack name="defaultStack">
<interceptor-ref name="exception"/>
<interceptor-ref name="alias"/>
<interceptor-ref name="servletConfig"/>
<interceptor-ref name="prepare"/>
<interceptor-ref name="i18n"/>
<interceptor-ref name="chain"/>
<interceptor-ref name="debugging"/>
<interceptor-ref name="profiling"/>
<interceptor-ref name="scopedModelDriven"/>
<interceptor-ref name="modelDriven"/>
<interceptor-ref name="fileUpload"/>
<interceptor-ref name="checkbox"/>
<interceptor-ref name="staticParams"/>
<interceptor-ref name="params">
<param name="excludeParams">dojo\..*</param>
</interceptor-ref>
<interceptor-ref name="conversionError"/>
<interceptor-ref name="validation">
<param name="excludeMethods">input,back,cancel,browse</param>
</interceptor-ref>
<interceptor-ref name="workflow">
<param name="excludeMethods">input,back,cancel,browse</param>
</interceptor-ref>
</interceptor-stack>
<interceptor-stack name="completeStack">
<interceptor-ref name="defaultStack"/>
</interceptor-stack>
<interceptor-stack name="executeAndWaitStack">
<interceptor-ref name="execAndWait">
<param name="excludeMethods">input,back,cancel</param>
</interceptor-ref>
<interceptor-ref name="defaultStack"/>
<interceptor-ref name="execAndWait">
<param name="excludeMethods">input,back,cancel</param>
</interceptor-ref>
</interceptor-stack>
<interceptor name="external-ref" class="com.opensymphony.xwork2.interceptor.ExternalReferencesInterceptor"/>
<interceptor name="model-driven" class="com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor"/>
<interceptor name="static-params" class="com.opensymphony.xwork2.interceptor.StaticParametersInterceptor"/>
<interceptor name="scoped-model-driven" class="com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor"/>
<interceptor name="servlet-config" class="org.apache.struts2.interceptor.ServletConfigInterceptor"/>
<interceptor name="token-session" class="org.apache.struts2.interceptor.TokenSessionStoreInterceptor"/>
</interceptors>
<!--定義默認攔截器為"defaultStack"-->
<default-interceptor-ref name="defaultStack"/>