struts2和servlet的共存问题

刺骨的言语ヽ痛彻心扉 2022-08-04 14:40 168阅读 0赞

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：  
**  
<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>  
<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>

**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****.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：  
**  
<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>  
  
****  
<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>  
<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>

参考：

## 如何让struts2和servlet的共存 ##