servlet forward action问题以及struts2拦截servlet问题

 

其实这个问题自己以前就遇到过了但当时没有深入解决就下了定论：Servlet是不能转发到Action的。今天看到他人也有这个问题，所以特意的深入了一下也看了他人的资料。

           这个问题的原因是filter默认拦截的是request，而forwardfilter是不会拦截的，所以想要想struts2拦截forward就需要配置：

Java代码  

1. <filter>   
2.         <filter-name>struts2</filter-name>   
3.         <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>   
4.     </filter>   
5.   
6.     <filter-mapping>   
7.         <filter-name>struts2</filter-name>   
8.         <url-pattern>/*</url-pattern>   
9.         <dispatcher>request</dispatcher>   
10.         <dispatcher>forward</dispatcher>   
11.     </filter-mapping>  

<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>        <dispatcher>request</dispatcher>        <dispatcher>forward</dispatcher>    </filter-mapping>

 

另一个问题就是struts2的核心filter配置的是"/*"所以他会拦截所有的请求，如果你配有servlet，你的请求是会先被filter拦截的也就是会进入struts2的流程而不是servlet的，但有时你又真的需要使用的servlet（就像你要整合DWR），为了解决这种情况也有两种解决方案：

              1，在struts2 core包org.apache.struts2下的default.properties：修改这个键值对struts.action.extension=action，当然我们不希望直接在这个文件里改，可以通过在struts.xml中增加常量的方式来配置

                2，在web.xml里添加一个拦截器，过滤我们的Servlet。web.xml文件内容：

Java代码  

1. <!-- 自定义过滤器，过滤servlet请求。解决struts和servlet冲突问题 -->      
2.     <filter>      
3.       <filter-name>ServletFilter</filter-name>      
4.       <filter-class>org.bts.base.filter.ServletFilters</filter-class>      
5.       <init-param>      
6.         <param-name>includeServlets</param-name>      
7.         <param-value>proxool_admin</param-value>      
8.       </init-param>      
9.     </filter>      
10.     <filter-mapping>      
11.       <filter-name>ServletFilter</filter-name>      
12.       <url-pattern>/*</url-pattern>      
13.     </filter-mapping>      
14.            
15.     <!-- 定义Struts2的FilterDispathcer的Filter -->      
16.  <filter>      
17.         <filter-name>struts2</filter-name>      
18.         <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>      
19.  </filter>      
20.  <!-- FilterDispatcher用来初始化struts2并且处理所有的WEB请求 -->      
21.  <filter-mapping>      
22.   <filter-name>struts2</filter-name>      
23.   <url-pattern>/*</url-pattern>      
24.  </filter-mapping>      
25.       
26.   <!-- 用于初始化Spring容器的Listener -->      
27.  <context-param>      
28.   <param-name>contextConfigLocation</param-name>      
29.    <param-value>WEB-INF/classes/applicationContext.xml</param-value>      
30.  </context-param>      
31.  <listener>      
32.         <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>      
33.  </listener>      
34.       
35.     <!-- 配置proxool管理工具 -->      
36.  <servlet>      
37.    <servlet-name>proxool_admin</servlet-name>      
38.    <servlet-class>org.logicalcobwebs.proxool.admin.servlet.AdminServlet </servlet-class>      
39.  </servlet>      
40.  <servlet-mapping>      
41.    <servlet-name>proxool_admin</servlet-name>      
42.    <url-pattern>/proxool_admin</url-pattern>      
43.  </servlet-mapping>      
44.  <security-constraint>      
45.    <web-resource-collection>      
46.      <web-resource-name>proxool</web-resource-name>      
47.      <url-pattern>/proxool_admin</url-pattern>      
48.    </web-resource-collection>      
49.    <auth-constraint>      
50.      <role-name>manager</role-name>      
51.    </auth-constraint>      
52.  </security-constraint>      
53.  <login-config>      
54.    <auth-method>BASIC</auth-method>      
55.    <realm-name> proxool manager Application</realm-name>      
56.  </login-config>      
57.  <security-role>      
58.    <description>      
59.      The role that is required to log in to the Manager Application       
60.    </description>      
61.    <role-name>manager</role-name>      
62.  </security-role>      
63.  <error-page>      
64.    <error-code>401</error-code>      
65.    <location>/jsp/error/401.jsp</location>      
66.  </error-page>     

<!-- 自定义过滤器，过滤servlet请求。解决struts和servlet冲突问题 -->       <filter>         <filter-name>ServletFilter</filter-name>         <filter-class>org.bts.base.filter.ServletFilters</filter-class>         <init-param>           <param-name>includeServlets</param-name>           <param-value>proxool_admin</param-value>         </init-param>       </filter>       <filter-mapping>         <filter-name>ServletFilter</filter-name>         <url-pattern>/*</url-pattern>       </filter-mapping>               <!-- 定义Struts2的FilterDispathcer的Filter -->    <filter>           <filter-name>struts2</filter-name>           <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>    </filter>    <!-- FilterDispatcher用来初始化struts2并且处理所有的WEB请求 -->    <filter-mapping>     <filter-name>struts2</filter-name>     <url-pattern>/*</url-pattern>    </filter-mapping>        <!-- 用于初始化Spring容器的Listener -->    <context-param>     <param-name>contextConfigLocation</param-name>      <param-value>WEB-INF/classes/applicationContext.xml</param-value>    </context-param>    <listener>           <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>    </listener>          <!-- 配置proxool管理工具 -->    <servlet>      <servlet-name>proxool_admin</servlet-name>      <servlet-class>org.logicalcobwebs.proxool.admin.servlet.AdminServlet </servlet-class>    </servlet>    <servlet-mapping>      <servlet-name>proxool_admin</servlet-name>      <url-pattern>/proxool_admin</url-pattern>    </servlet-mapping>    <security-constraint>      <web-resource-collection>        <web-resource-name>proxool</web-resource-name>        <url-pattern>/proxool_admin</url-pattern>      </web-resource-collection>      <auth-constraint>        <role-name>manager</role-name>      </auth-constraint>    </security-constraint>    <login-config>      <auth-method>BASIC</auth-method>      <realm-name> proxool manager Application</realm-name>    </login-config>    <security-role>      <description>        The role that is required to log in to the Manager Application       </description>      <role-name>manager</role-name>    </security-role>    <error-page>      <error-code>401</error-code>      <location>/jsp/error/401.jsp</location>    </error-page>   

 过滤器的实现

Java代码  

1. package org.bts.base.filter;       
2.       
3. import java.io.IOException;       
4. import java.util.ArrayList;       
5. import java.util.Arrays;       
6. import java.util.List;       
7.       
8. import javax.servlet.Filter;       
9. import javax.servlet.FilterChain;       
10. import javax.servlet.FilterConfig;       
11. import javax.servlet.RequestDispatcher;       
12. import javax.servlet.ServletException;       
13. import javax.servlet.ServletRequest;       
14. import javax.servlet.ServletResponse;       
15. import javax.servlet.http.HttpServletRequest;       
16.       
17. public class ServletFilters implements Filter {       
18.       
19.     private List<String> initParameters = new ArrayList<String>();       
20.     @Override      
21.     public void destroy() {       
22.        System.out.println("ServletFilters destroied!");       
23.     }       
24.       
25.     @Override      
26.     public void doFilter(ServletRequest req, ServletResponse resp,FilterChain chain) throws IOException, ServletException {       
27.                
28.         HttpServletRequest request = (HttpServletRequest) req;       
29.         String target = request.getRequestURI();       
30.         System.out.println("1: "+target);       
31.         target = target.lastIndexOf("?") > 0 ? target.substring(target       
32.                 .lastIndexOf("/") + 1, target.lastIndexOf("?")       
33.                 - target.lastIndexOf("/")) : target.substring(target       
34.                 .lastIndexOf("/") + 1);       
35.           System.out.println("2:"+target);       
36.         if (this.initParameters.contains(target)) {       
37.             RequestDispatcher rdsp = request.getRequestDispatcher(target);       
38.             rdsp.forward(req, resp);//转发我们的请求，跳出FilterChain      
39.         } else      
40.             chain.doFilter(req, resp);       
41.       
42.     }       
43.       
44.     @Override      
45.     public void init(FilterConfig config) throws ServletException {       
46.         String parameters = config.getInitParameter("includeServlets");       
47.         System.out.println("************"+config.getFilterName()+" initing with value "+parameters+"********************");       
48.         this.initParameters.addAll(Arrays.asList(parameters.split(",")));       
49.     }       
50.       
51. }      

package org.bts.base.filter;       import java.io.IOException;    import java.util.ArrayList;    import java.util.Arrays;    import java.util.List;       import javax.servlet.Filter;    import javax.servlet.FilterChain;    import javax.servlet.FilterConfig;    import javax.servlet.RequestDispatcher;    import javax.servlet.ServletException;    import javax.servlet.ServletRequest;    import javax.servlet.ServletResponse;    import javax.servlet.http.HttpServletRequest;       public class ServletFilters implements Filter {           private List<String> initParameters = new ArrayList<String>();        @Override       public void destroy() {           System.out.println("ServletFilters destroied!");        }           @Override       public void doFilter(ServletRequest req, ServletResponse resp,FilterChain chain) throws IOException, ServletException {                        HttpServletRequest request = (HttpServletRequest) req;            String target = request.getRequestURI();            System.out.println("1: "+target);            target = target.lastIndexOf("?") > 0 ? target.substring(target                    .lastIndexOf("/") + 1, target.lastIndexOf("?")                    - target.lastIndexOf("/")) : target.substring(target                    .lastIndexOf("/") + 1);              System.out.println("2:"+target);            if (this.initParameters.contains(target)) {                RequestDispatcher rdsp = request.getRequestDispatcher(target);                rdsp.forward(req, resp);//转发我们的请求，跳出FilterChain            } else               chain.doFilter(req, resp);           }           @Override       public void init(FilterConfig config) throws ServletException {            String parameters = config.getInitParameter("includeServlets");            System.out.println("************"+config.getFilterName()+" initing with value "+parameters+"********************");            this.initParameters.addAll(Arrays.asList(parameters.split(",")));        }       }    

 

我个人比较倾向于第一种方法，第二种方案我没有自己测试，来源与他人的文章，使用第一种就是每次要用到action时要在请求url后面加“.action”，当然你如果使用的是struts2的标签那么他会自动加的，而且我认为有.action用来区分其他处理请求和struts的处理请求是需要的。