JavaWeb19.7【Filter&Listener：案例2-敏感词汇过滤】

基于day17_base项目

 

 

 

 

 

package com.haifei.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;

/**
 * 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 {
                //判断方法名是否是 getParameter
                if (method.getName().equals("getParameter")){
                    //增强返回值

                    //获取原返回值，找到敏感词汇，并替换为***
                    String value = (String) method.invoke(req, args);
                    if (value != null){
                        for (String str : list) {
                            if (value.contains(str)){
                                value = value.replaceAll(str, "***");
                            }
                        }
                    }
                    return value;
                }else {
                    return method.invoke(req, args);
                }

                //判断方法名是否是 getParameterMap
                //判断方法名是否是 getParameterValue
            }
        });

        //2 放行
        chain.doFilter(proxy_req, resp);
    }

    private List<String> list = new ArrayList<>(); //敏感词汇集合

    public void init(FilterConfig config) throws ServletException {
        try {
            //获取敏感词汇配置文件的真实路径
            ServletContext servletContext = config.getServletContext();
            String realPath = servletContext.getRealPath("/WEB-INF/classes/敏感词汇.txt");//src下资源的真实路径获取

            //读取文件，将文件的每一行数据添加到list
            BufferedReader br = new BufferedReader(new FileReader(realPath)); //br默认GBK？文件改为GBK编码，不然读取出来的数据乱码
            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() {

    }

}

package com.haifei.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("/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);
    }
}

?

1 2 3 4

坏蛋 笨蛋 混蛋 王八蛋