使用动态代理对象进行敏感字过滤

Posted 2022-10-27 newcityboy

package com.hopetesting.web.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;

/**
 * @author newcityman
 * @date 2019/9/13 - 19:41
 */
@WebFilter("/*")
public class SensitiveWordsFilter implements Filter 
    public void destroy() 
    

    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 
                //判断是否是getParameter方法
                //如果是，增强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.replace(str, "******");
                            
                        
                    
                    return value;
                
                return method.invoke(req, args);
            
        );
        chain.doFilter(proxy_req, resp);
    

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

    public void init(FilterConfig config) throws ServletException 
        try 
            //1、获取文件的真实路径
            ServletContext servletContext = config.getServletContext();
            String realPath = servletContext.getRealPath("/WEB-INF/classes/敏感词汇.txt");
            //2、读取文件
            BufferedReader br = new BufferedReader(new FileReader(realPath));
            //3、将文件的每一行读取到list中
            String line = null;
            while ((line = br.readLine()) != null) 
                list.add(line);
            
            br.close();
            System.out.println(list);
         catch (FileNotFoundException e) 
            e.printStackTrace();
         catch (IOException e) 
            e.printStackTrace();