1 关于在Struts2的自定义的验证拦截器（Interceptor）中的invocation.invoke()是什么意思？
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5
6 package com.xjtu.interceptor;
7
8 import com.opensymphony.xwork2.ActionContext;
9 import com.opensymphony.xwork2.ActionInvocation;
10 import com.opensymphony.xwork2.interceptor.Interceptor;
11
12 public class PermissionInterceptor implements Interceptor {
13
14 /**
15 *
16 */
17 private static final long serialVersionUID = 1L;
18
19 @Override
20 public void destroy() {
21 // TODO Auto-generated method stub
22
23 }
24
25 @Override
26 public void init() {
27 // TODO Auto-generated method stub
28
29 }
30
31 @Override
32 public String intercept(ActionInvocation invocation) throws Exception {
33 System.out.println("进入拦截器");
34 Object user = ActionContext.getContext().getSession().get("user");
35 System.out.println(user);
36 if (user != null) {
37 return invocation.invoke();
38 }
39 ActionContext.getContext().put("message", "您无权执行该操作！");
40 return "success";
41 }
42
43 }
44
45
46
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48
49
50 package com.xjtu.soft;
51
52 public class HelloWorldAction {
53 private String message;
54
55 public String getMessage() {
56 return message;
57 }
58
59 public void setMessage(String message) {
60 this.message = message;
61 }
62
63 public String execute(){
64 System.out.println("执行execute");
65 message = "execute";
66 return "success";
67 }
68
69 public String addUI() {
70 System.out.println("执行addUI");
71 message = "addUI";
72 return "success";
73 }
74
75
76 }
77
78
79
80 struts.xml配置自定义的拦截器如下：
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83
84
85 <?xml version="1.0" encoding="UTF-8" ?>
86 <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd">
87 <struts>
88 <constant name="struts.action.extension" value="do,action" />
89 <constant name="struts.multipart.maxSize" value="10485760" />
90
91
92 <package name="itcast" namespace="/test" extends="struts-default">
93 <interceptors>
94 <interceptor name="permission"
95 class="com.xjtu.interceptor.PermissionInterceptor" />
96 <interceptor-stack name="permissionstack">
97 <interceptor-ref name="defaultStack"></interceptor-ref>
98 <interceptor-ref name="permission"></interceptor-ref>
99 </interceptor-stack>
100 </interceptors>
101
102 <global-results>
103 <result name="success">/WEB-INF/page/message.jsp</result>
104 </global-results>
105
106 <action name="list_*" class="com.xjtu.soft.HelloWorldAction"
107 method="{1}">
108 <interceptor-ref name="permissionstack"></interceptor-ref>
109 </action>
110 </package>
111
112 </struts>
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116
117 invocation.invoke() 就是通知struts2接着干下面的事情
118 比如 调用下一个拦截器 或 执行下一个Action
119 就等于退出了你自己编写的这个interceptor了
120
121
122 如何使用struts2拦截器，或者自定义拦截器。特别注意，在使用拦截器的时候，在Action里面必须最后一定要引用struts2自带的拦截器缺省堆栈defaultStack,如下(这里我是引用了struts2自带的checkbox拦截器)：
123
124 <interceptor-ref name="checkbox">
125 <param name="uncheckedValue">0</param>
126 </interceptor-ref>
127 <interceptor-ref name="defaultStack"/>
128 ******(必须加，否则出错)
