使用struts2时定义一个servlet过滤器

我一般使用struts2的时候都是匹配所有类型的，这时候就会出现一个问题，当去访问一个servlet的时候就系统会把它当作一个action来访问，就会出现找不到action的问题。所以这个时候就需要实现一个filter来过滤servlet，并且这个filter要放在struts2的filter之前，要在把它当作一个action之前直接把它进行跳转访问servlet

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代码：

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.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class ServletFilter implements Filter {private List<String> targets = new ArrayList<String>();public void destroy() {// TODO Auto-generated method stub}public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {// TODO Auto-generated method stubHttpServletRequest req = (HttpServletRequest)request;HttpServletResponse resp = (HttpServletResponse)response;String uri = req.getRequestURI();String target = uri.indexOf("?") > 0 ? uri.substring((uri.lastIndexOf("/")+1),uri.indexOf("?")) : uri.substring(uri.lastIndexOf("/")+1);//servlet的URL用的都是servlet/servlet的名称if (uri.contains("servlet") && targets.contains(target)) {req.getRequestDispatcher(uri.substring(9)).forward(req, resp);} else {chain.doFilter(req, resp);}}public void init(FilterConfig config) throws ServletException {// TODO Auto-generated method stubString targets = config.getInitParameter("targets");//在web.xml里面声明的filter里面的参数指定哪些servlet是需要过滤的，也可以不指定，直接过滤所有的servletthis.targets.addAll(Arrays.asList(targets.split(",")));}}