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Filter Mapping Url-pattern That Excludes Subdirectories

需求其实就是把eclipse osgi导出的应用嵌入到原有的ssh开发的程序中。 但是整合过程遇到一些问题。ssh会对资源进行拦截处理,导致OSGi获取不到请求,OSGi和ssh的应用最好分开管理。 可以利用SSH提供的excludePattern配置正则表达式来实现排除处理!

Struts拦截器配置

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<filter> 
  <filter-name>struts-cleanup</filter-name> 
  <filter-class> 
   org.apache.struts2.dispatcher.ActionContextCleanUp 
  </filter-class> 
</filter>
<filter-mapping> 
  <filter-name>struts-cleanup</filter-name> 
  <url-pattern>/*</url-pattern> 
</filter-mapping> 

<filter>
  <filter-name>struts</filter-name>
  <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>     
</filter>
<filter-mapping>
  <filter-name>struts</filter-name>
  <url-pattern>*.action</url-pattern>
</filter-mapping>
<filter-mapping>
  <filter-name>struts</filter-name>
  <url-pattern>*.do</url-pattern>
</filter-mapping>
<filter-mapping>
  <filter-name>struts</filter-name>
  <url-pattern>*.htm</url-pattern>
</filter-mapping>
<filter-mapping>
  <filter-name>struts</filter-name>
  <url-pattern>/struts/*</url-pattern>
</filter-mapping>

添加OSGi支持

把eclipse osgi应用嵌入需要在web.xml中添加:

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<servlet id="bridge">
  <servlet-name>equinoxbridgeservlet</servlet-name>
  <servlet-class>org.eclipse.equinox.servletbridge.BridgeServlet</servlet-class>
  <init-param>
      <param-name>commandline</param-name>
      <param-value>-console</param-value>         
  </init-param>     
  <init-param>
      <param-name>enableFrameworkControls</param-name>
      <param-value>true</param-value>         
  </init-param>
  <init-param>
      <param-name>extendedFrameworkExports</param-name>
      <param-value></param-value>         
  </init-param> 
  <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
  <servlet-name>equinoxbridgeservlet</servlet-name>
  <url-pattern>
      /osgi/*
  </url-pattern>
</servlet-mapping>

整合遇到的问题及解决

由于struts的filter过滤了htm,导致osgi的htm文件被struts”劫”取了~~

经过一番挣扎,解决方法如下:

在struts过滤器中增加排除参数。

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  <filter>
      <filter-name>struts</filter-name>
      <filter-class>
          org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
      </filter-class>
      <init-param>
          <param-name>struts.action.excludePattern</param-name>
          <param-value>/osgi/.*</param-value>
      </init-param>
  </filter>

为啥怎么弄,解释如下:

1 读取init-param初始化参数excludedPatterns

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protected List<Pattern> excludedPatterns = null;

public void init(FilterConfig filterConfig) throws ServletException {
    InitOperations init = new InitOperations();
    try {
        FilterHostConfig config = new FilterHostConfig(filterConfig);
        init.initLogging(config);
        Dispatcher dispatcher = init.initDispatcher(config);
        init.initStaticContentLoader(config, dispatcher);

        prepare = new PrepareOperations(filterConfig.getServletContext(), dispatcher);
        execute = new ExecuteOperations(filterConfig.getServletContext(), dispatcher);
        this.excludedPatterns = init.buildExcludedPatternsList(dispatcher); // 获取不被Struts处理的请求Regex模式

        postInit(dispatcher, filterConfig);
    } finally {
        init.cleanup();
    }

}

2 使用excludedPatterns

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public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) 
                    throws IOException, ServletException {
    //父类向子类转:强转为httpReq请求、httpResp响应
    HttpServletRequest request = (HttpServletRequest) req;
    HttpServletResponse response = (HttpServletResponse) res;

  try {
      //。。。@@根据Regex模式(excludedPatterns)对请求进行处理
      if ( excludedPatterns != null && prepare.isUrlExcluded(request, excludedPatterns)) {
          chain.doFilter(request, response);
      } else {
          request = prepare.wrapRequest(request);
          ActionMapping mapping = prepare.findActionMapping(request, response, true);
          if (mapping == null) {
              boolean handled = execute.executeStaticResourceRequest(request, response);
              if (!handled) {
                  chain.doFilter(request, response);
              }
          } else {
              execute.executeAction(request, response, mapping);
          }
      }
  } finally {
       prepare.cleanupRequest(request);
  }
}

后记

其实SSH就是对请求进行过滤拦截转发!Struts提供了不处理请求配置罢了。

看到的其他实现:

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// First cast ServletRequest to HttpServletRequest.
HttpServletRequest hsr = (HttpServletRequest) request;

// Check if requested resource is not in /test folder.
if (!hsr.getServletPath().startsWith("/test/")) {
  // Not in /test folder. Do your thing here.
}

web.xml中的3种写法

  1. 完全匹配 /test/list.do
  2. 目录匹配 /test/*
  3. 扩展名匹配 *.do

servlet-mapping的重要规则:

  • 容器会首先查找完全匹配,如果找不到,再查找目录匹配,如果也找不到,就查找扩展名匹配。
  • 如果一个请求匹配多个“目录匹配”,容器会选择最长的匹配。

参考资源:


【原文地址】

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