敏感字符的过滤

Posted 2020-11-22 naigai

@WebFilter("/*")
public class SensitiverWordsFilter implements Filter {


    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {

        //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;
                }
                return method.invoke(req,args);
            }
        });
        chain.doFilter(proxy_req, resp);
    }

    //敏感词汇的list集合
    private List<String> list = new ArrayList<String>();
    public void init(FilterConfig config) throws ServletException {
        try {
            //加载文件
            ServletContext servletContext = config.getServletContext();
            //获取服务器下的真实路径
            String realPath = servletContext.getRealPath("/WEB-INF/classes/敏感词汇.txt");
            //读取文件
            BufferedReader br = new BufferedReader(new FileReader(realPath));
            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() {
    }
}