WARN org.apache.struts2.dispatcher.Dispatcher - Could not find action or result

下面是jsp页面：

<form action="servlet/ShowData" method="post">

查询公司ID<input type="text" name="com_id" size="15"><br> <br>

<input type="submit" value="查询" />

</form>

下面是web的配置文件

<servlet>

    <description>This is the description of my J2EE component</description>

    <display-name>This is the display name of my J2EE component</display-name>

    <servlet-name>ShowData</servlet-name>

    <servlet-class>com.cn.data.ShowData</servlet-class>

  </servlet>

  <servlet-mapping>

    <servlet-name>ShowData</servlet-name>

    <url-pattern>/servlet/ShowData</url-pattern>

  </servlet-mapping>

开发环境是myeclipse，ShowData是一个Servlet文件，运行是报错如下：

WARN org.apache.struts2.dispatcher.Dispatcher - Could not find action or result: /Website/servlet/ShowData
There is no Action mapped for action name servletN. - [unknown location]
at com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:185)
at org.apache.struts2.impl.StrutsActionProxy.prepare(StrutsActionProxy.java:63)
at org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:37)
at com.opensymphony.xwork2.DefaultActionProxyFactory.createActionProxy(DefaultActionProxyFactory.java:58)
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:554)
at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)

一、问题的提出
   先让我们看下web.xml中struts2和servlet的配置：
    <!-- struts2拦截页面请求的配置 -->

   <filter>

        <filter-name>struts2</filter-name>

        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>

    </filter>

    <filter-mapping>

        <filter-name>struts2</filter-name>

        <url-pattern>/*</url-pattern>

    </filter-mapping>

     <!-- servlet的配置 -->

    <servlet>

        <servlet-name>ImageServlet</servlet-name>

        <servlet-class>com.servlets.ImageServlet

        </servlet-class>

    </servlet>

    <servlet-mapping>

        <servlet-name>ImageServlet</servlet-name>

        <url-pattern>/myImageServlet/*</url-pattern>

    </servlet-mapping>

  当我们在页面在请求应用时，struts2将会截获所有请求，对于servlet请求将不能够正常响应的
（报错信息为：HTTP
Status 404 - There is no Action mapped for namespace / and action name myImageServlet.）,
这是因为struts2把servlet当成action了，因为servlet和action都是没有后缀的.

二、解决方案

   解决方法目前有四种：
方法1：

   统一在servlet后面加上.servlet结尾（包括web.xml配置文件中和页面上使用servlet的地方）

   (备注：我使用的就是这种办法)

如下所示：

下面是修改之后的jsp页面：

<form action="servlet/ShowData.servlet" method="post">

查询公司ID<input type="text" name="com_id" size="15"><br> <br>

<input type="submit" value="查询" />

</form>

[b]下面是修改之后的web的配置文件

<servlet>

    <description>This is the description of my J2EE component</description>

    <display-name>This is the display name of my J2EE component</display-name>

    <servlet-name>ShowData</servlet-name>

    <servlet-class>com.cn.data.ShowData</servlet-class>

  </servlet>

  <servlet-mapping>

    <servlet-name>ShowData</servlet-name>

    <url-pattern>/servlet/ShowData[/b].servlet</url-pattern>

  </servlet-mapping>

方法2（比较通用奥）：

    在struts.xml中的<struts>的节点下面添加struts2处理的请求后缀 常量：
<!--  
该属性指定需要Struts
2处理的请求后缀，该属性的默认值是action，即所有匹配*.action的请求都由Struts
2处理。 
如果用户需要指定多个请求后缀，则多个后缀之间以英文逗号（，）隔开。 

 --> 

<constant name="struts.action.extension" value="action" /> 

方法3：

     在web.xml中修改struts2拦截页面请求的配置：
原：

   <filter>

        <filter-name>struts2</filter-name>

        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>

    </filter>

    <filter-mapping>

        <filter-name>struts2</filter-name>

        <url-pattern>/*</url-pattern>

    </filter-mapping>

现：

   <filter-mapping>

      <filter-name>struts2</filter-name>

      <url-pattern>*.action</url-pattern>

   </filter-mapping>

   <filter-mapping>

      <filter-name>struts2</filter-name>

      <url-pattern>*.jsp</url-pattern>

   </filter-mapping>

   <filter-mapping>

      <filter-name>struts2</filter-name>

      <url-pattern>/user/*</url-pattern>

   </filter-mapping>

  servlet的请求路径不必改变

方法4：

     自定义filter对servlet进行过滤：

##############################################

# 该类是定义了一个过滤器（随便你放在摸个包下面），当既用到struts2有用到servlet时，

# 必须用该过滤器对所有的servlet做一次过滤，否则servlet将无法正常运行。

# 同时在web.xml中，在定义struts的核心控制器的过滤器前面添加该过滤器，添加代码如下：

* <filter>

*   <filter-name>redisp</filter-name>

*   <filter-class>filters.ReDispatcherFilter（该过滤器的类名）</filter-class>

*   <init-param>

*    <param-name>includeServlets</param-name>

*    <param-value>所配置的servlet，注意是那url-pattern</param-value>

*   </init-param>

* </filter>

* <filter-mapping>

*   <filter-name>redisp</filter-name>

*   <url-pattern>/*</url-pattern>

* </filter-mapping>

*该类也可以直接继承StrutsPrepareAndExecuteFilter的

###########################################################

public class ReDispatcherFilter implements Filter {

public void destroy() {

   // TODO Auto-generated method stub

}

public void doFilter(ServletRequest req, ServletResponse resp,

    FilterChain chain) throws IOException, ServletException

{

 

   HttpServletRequest request = (HttpServletRequest)req;

   String target = request.getRequestURI();

   target = target.lastIndexOf("?")>0  

 ?target.substring(target.lastIndexOf("/")+1,target.lastIndexOf("?")-target.lastIndexOf("/"))

      :target.substring(target.lastIndexOf("/")+1);

   System.out.println(target);

   if(this.includes.contains(target))

   {

    RequestDispatcher rdsp = request.getRequestDispatcher(target);  

    System.out.println("go..............."+rdsp);

    rdsp.forward(req, resp);

   }

   else

    chain.doFilter(req, resp);

}

private ArrayList<String> includes = new ArrayList<String>();

public void init(FilterConfig config) throws ServletException {

   this.includes.addAll( Arrays.asList(config.getInitParameter("includeServlets").split(",")));

}

}
怕大家还是配置错误，给一个web.xml的配置实例。

  <filter>

        <filter-name>redisp</filter-name>

        <filter-class>

com.xheditor.servlet.ReDispatcherFilter</filter-class>

        <init-param>

            <param-name>includeServlets</param-name>

            <param-value>UploadFileServlet</param-value>

           </init-param>

     </filter>

    <filter-mapping>

        <filter-name>redisp</filter-name>

        <url-pattern>/*</url-pattern>

    </filter-mapping>

     
<!-- struts2拦截页面请求的配置 -->

   <filter>

        <filter-name>struts2</filter-name>

        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>

    </filter>

    <filter-mapping>

        <filter-name>struts2</filter-name>

        <url-pattern>/*</url-pattern>

    </filter-mapping>

    <!-- servlet的配置 -->

    <servlet>

        <servlet-name>ImageServlet</servlet-name>

        <servlet-class>com.servlets.ImageServlet

        </servlet-class>

    </servlet>

    <servlet-mapping>

        <servlet-name>ImageServlet</servlet-name>

        <url-pattern>/myImageServlet/*</url-pattern>

    </servlet-mapping>

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