Filter过滤敏感词汇分析与实现

Filter过滤敏感词汇案例

　　需求∶

　　　　1．对用户信息案例录入的数据进行敏感词汇过滤

　　　　2．敏感词汇参考 傻蛋.坏蛋......

　　　　3．如果是敏感词汇，替换为***

　　分析：

　　　　1.对request对象进行增强。增强获取参数相关方法

　　　　2.放行。传递代理对象

 

 

 SensitiveWordsFilter：

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

    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 {
                //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;
                }

                //判断是否是getParameterMap
                if (method.getName().equals("getParameterMap")){
                    Map<String,String[]>map=(Map<String, String[]>) method.invoke(req,args);//真实返回值
                    Map<String,String[]> remap=new HashMap<>();
                    Set<String> strings = map.keySet();
                    for (String key:strings){//遍历map
                        String value[]=map.get(key);
                        for (String str:list){//遍历敏感词
                            if (value[0].contains(str)){
                                value[0]=value[0].replaceAll(str,"***");
                            }
                        }
                    }
                    return map;
                }
                //判断是否是getParameterValue
                if (method.getName().equals("getParameterValue")){
                    String values[]= (String[]) method.invoke(req,args);
                    for (int i=0;i<values.length;i++){
                        for (String str:list){
                            if (values[i].equals(str)){
                                values[i]=values[i].replaceAll(str,"***");
                            }
                        }
                    }
                    return values;
                }

                return method.invoke(req,args);
            }
        });
        chain.doFilter(proxy_req, resp);
    }
    public List<String> list = new ArrayList<String>();//敏感词汇集合
    public void init(FilterConfig config) throws ServletException {
        try {
            //获取文件的真实加载文件
            ServletContext servletContext = config.getServletContext();
            String realPath = servletContext.getRealPath("/WEB-INF/classes/敏感词汇.txt");
            //读取文件
            BufferedReader br = new BufferedReader(new FileReader(realPath));
            String len = null;
            while ((len=br.readLine())!=null){
                list.add(len);
            }
            br.close();
            System.out.println(list);
        }catch (IOException e) {
            e.printStackTrace();
        }

    }

}

敏感词汇.txt：GBK形式

乱码的需要用这个new BufferedReader(new InputStreamReader(new FileInputStream(realPath),"GBK"))

@WebServlet("/testServlet")
public class TestServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String name = request.getParameter("name");
        String msg = request.getParameter("msg");
        System.out.println(name+":"+msg);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}