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w222

自己编写了一个简单的特殊字符过滤器，但是报错，代码如下：
package com.wsf;

import java.io.IOException;

import javax.Servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class OutputReplaceFilter implements Filter {

        public void destroy() {

               
        }


        public void doFilter(ServletRequest request, ServletResponse response,
                        FilterChain chain) throws IOException, ServletException {
       
                HttpServletRequest req=(HttpServletRequest) request;
                HttpServletResponse res=(HttpServletResponse) response;
               
                String username=req.getParameter("id");
                System.out.print("33333333333333");
                username=username.replaceAll("bai","en");
                req.setAttribute("username", username);
               
                chain.doFilter(request,response);
               
        }


        public void init(FilterConfig filterConfig) throws ServletException {

               
        }

}

报错的是username=username.replaceAll("bai","en");求告知

admin

你获取的id是不是为null？

admin

直接用replace就好了 可以全部替换 replaceAll需要用到正则。