Fitter-案例-过滤敏感词汇-分析 Fitter-案例-过滤敏感词汇-代码实现

Fitter-案例-过滤敏感词汇-分析

需求：

　　1. 对day17_case案例录入的数据进行敏感词汇过滤

　　2. 敏感词汇参考《敏感词汇.txt》

　　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

Fitter-案例-过滤敏感词汇-代码实现

package com.example.day17_case.web.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.List;


@WebFilter("/*")
public class SensitiveWordsFilter implements Filter {
    //敏感词汇集合
    private List<String> list = new ArrayList<String>();
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {


        try {
            //获取文件真实路径
            ServletContext servletContext = filterConfig.getServletContext();
            String realPath = servletContext.getRealPath("/WEB-INF/敏感词汇.txt");

            //读取文件
            BufferedReader bufferedReader = new BufferedReader(new FileReader(realPath));

            //将文件的每一行数据添加到list中
            String line = null;
            while((line = bufferedReader.readLine())!=null){
                list.add(line);
            }
            bufferedReader.close();
            System.out.println(list);
        }catch (Exception e){
            e.printStackTrace();
        }

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

        //创建代理对象，增强getParameter方法
        ServletRequest proxy_req = (ServletRequest) Proxy.newProxyInstance(servletRequest.getClass().getClassLoader(), servletRequest.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(servletRequest,servletResponse);
                    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(proxy_req,servletResponse);
    }

    @Override
    public void destroy() {
        Filter.super.destroy();
    }
}

package com.example.day17_case.web.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/textServlet")
public class Textservlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String name = req.getParameter("name");
        String msg = req.getParameter("msg");

        System.out.println(name+":"+msg);
    }
}