Java实现过滤敏感词汇：
使用动态代理模式，增强返回值类型，替换敏感词汇
代码如下：
1、敏感词汇过滤器
package com.it.filter;import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
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;/*** @简单描述:敏感词汇过滤器* @Author:* @Date: 2022年03月16日 19时42分39秒*/
@WebFilter("/*")
public class SensitiveFilter 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() {@Overridepublic Object invoke(Object proxy, Method method, Object[] args) throws Throwable {//增强getParameter方法//判断是否有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 s : list) {if (value.contains(s)){value = value.replaceAll(s,"***");}}}return value;}return method.invoke(req, args);}});chain.doFilter(proxy_req, resp);}//敏感词汇集合private List<String> list = new ArrayList<String>();public void init(FilterConfig config) throws ServletException {try {//1、加载文件,获取文件真实路径ServletContext servletContext = config.getServletContext();String realPath = servletContext.getRealPath("/WEB-INF/classes/敏感词汇.txt");//2、读取文件BufferedReader bufferedReader = new BufferedReader(new FileReader(realPath));//3、将文件中的每一行数据添加到list集合中String line = null ;while ((line = bufferedReader.readLine()) != null){list.add(line);}bufferedReader.close();System.out.println(list);} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}public void destroy() {}
}
2、测试所需servlet
package com.it.controller;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;/*** @简单描述：测试所需servlet* @Author:* @Date: 2022年03月16日 20时03分21秒*/
@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");String info = name+":"+msg ;System.out.println(info);request.setAttribute("info",info);request.getRequestDispatcher("he.jsp").forward(request,response);}protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doPost(request, response);}
}
3、所需的前端界面:he.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>Title</title>
</head>
<body>
<div class="alert alert-warning alert-dismissible" role="alert"><button type="button" class="close" data-dismiss="alert" ><span>×</span></button><strong>${info}</strong>
</div>
</body>
</html>
4、直接在地址栏输入：
http://localhost:8080/userjdbc/testServlet?name=测试&msg=（你要输入的敏感词汇）
5、运行结果如下：
前端界面显示：
