Filter - 过滤敏感词汇(动态代理)

 /**
  * 敏感词汇过滤器
  */
 @WebFilter("/*")
 public class SensitiveWordsFilter implements Filter {

     public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {
         //1.创建代理对象，增强getParameter方法

         ServletRequest proxy_req = (ServletRequest) Proxy.newProxyInstance(req.getClass().getClassLoader(), req.getClass().getInterfaces(), new InvocationHandler() {
             @Override
             public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                 //增强getParameter方法
                 //判断是否是getParameter方法
                 if(method.getName().equals("getParameter")){
                     //增强返回值
                     //获取返回值
                     String value = (String) method.invoke(req,args);
                     if(value != null){
                         for (String str : list) {
                             if(value.contains(str)){
                                 value = value.replaceAll(str,"***");
                             }
                         }
                     }

                     return  value;
                 }

                 //判断方法名是否是 getParameterMap

                 //判断方法名是否是 getParameterValues

                 return method.invoke(req,args);
             }
         });

         //2.放行
         chain.doFilter(proxy_req, resp);
     }
     private List<String> list = new ArrayList<String>();//敏感词汇集合
     public void init(FilterConfig config) throws ServletException {

         try{
             //1.获取文件真实路径
             ServletContext servletContext = config.getServletContext();
             String realPath = servletContext.getRealPath("/WEB-INF/classes/敏感词汇.txt");　　// 敏感词汇.txt在src目录下
             //2.读取文件
             BufferedReader br = new BufferedReader(new FileReader(realPath));
             //3.将文件的每一行数据添加到list中
             String line = null;
             while((line = br.readLine())!=null){
                 list.add(line);
             }

             br.close();

             System.out.println(list);

         }catch (Exception e){
             e.printStackTrace();
         }

     }

     public void destroy() {
     }

 }