关于用动态代理增强request来进行敏感词过滤

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package servlet.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
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;

@WebFilter("/*")
public class FilterDemo3 implements Filter {
    ArrayList<String> arrayList = new ArrayList<>();
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        try {
        //获取真实路径
        ServletContext context = filterConfig.getServletContext();
        String realPath = context.getRealPath("/sensitiveWords.txt");
        BufferedReader br = new BufferedReader(new FileReader(realPath));
        String line = null;
        while((line=br.readLine())!=null){
            arrayList.add(line);
        }
        br.close();
        } catch (Exception e) {
           e.printStackTrace();
        }
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
            //进行代理
         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
                if(method.getName().equals("getParameter")){
                    String value = (String) method.invoke(servletRequest, args);
                    if(value!=null){
                        for (String s : arrayList) {
                            if(s.equals(value)){
                              value=  value.replaceAll(s,"***");
                            }
                        }
                    }
                    return value;

                }
                return method.invoke(servletRequest,args);
            }
        });
         filterChain.doFilter(Proxy_req,servletResponse);
    }

    @Override
    public void destroy() {

    }
}