Filter案例2_过滤敏感词汇实现、Listener监听器

Filter案例2_过滤敏感词汇实现

案例：

public class SensitivWordsFilter implements Filter {
    private List<String> list = new ArrayList<String>();//敏感词汇集合
    public void init(FilterConfig filterConfig) throws ServletException {
        try{
            //获取文件真实路径
            ServletContext servletContext = filterConfig.getServletContext();
            String realPath = servletContext.getRealPath("D:\\IDEA项目\\day_06\\src\\敏感词汇.txt");
            //读取文件
            BufferedReader br = new BufferedReader(new FileReader(realPath));
            //将文件的每一行添加到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 doFilter(final ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        ServletRequest proxy_lenovo = (ServletRequest) Proxy.newProxyInstance(servletRequest.getClass().getClassLoader(), servletRequest.getClass().getInterfaces(), new InvocationHandler() {
            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(servletRequest, args);
                    if (value!=null){
                        for (String str : list) {
                            if (value.contains(str)){
                                value=value.replaceAll(str,"***");
                            }
                        }
                    }
                    return value;
                }
                return method.invoke(servletRequest,args);
            }
        });
        //放行
        filterChain.doFilter(servletRequest,servletResponse);
    }

    public void destroy() {

    }