通过过滤器和增强request对象解决get提交请求服务器端乱码。

时间：2023-03-09 17:39:03
通过过滤器和增强request对象解决get提交请求服务器端乱码。

1.表单用get方式提交

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

    <form action="/WEB24/encodingServlet" method="get">

        <input type="text" name="username">

        <input type="submit" value="提交">

    </form>

</body>

</html>

2.创建一个servlet用于获取表单数据 并输出

package com.cc.servlet;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/**

 * Servlet implementation class EncodingServlet

 */

@WebServlet("/encodingServlet")

public class EncodingServlet extends HttpServlet {

    /**

     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

     */

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String parameter = request.getParameter("username");

        System.out.println(parameter);

    }

    /**

     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

     */

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        // TODO Auto-generated method stub

        doGet(request, response);

    }

}

3.创建过滤器，并增强request对象解决乱码

package com.cc.filter;

import java.io.IOException;

import java.io.UnsupportedEncodingException;

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.HttpServletRequestWrapper;

public class EncodingFilter implements Filter{

    @Override

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)

            throws IOException, ServletException {

        // TODO Auto-generated method stub

        //request.setCharacterEncoding("UTF-8");

        //被增强的对象

        HttpServletRequest req = (HttpServletRequest) request;

        EnhanceRequest enhanceRequest = new EnhanceRequest(req);

        chain.doFilter(enhanceRequest, response);

    }

    @Override

    public void init(FilterConfig filterConfig) throws ServletException {

        // TODO Auto-generated method stub

    }

    @Override

    public void destroy() {

        // TODO Auto-generated method stub

    }

    class EnhanceRequest extends HttpServletRequestWrapper{

        private HttpServletRequest request;

        public EnhanceRequest(HttpServletRequest request){

            super(request);

            this.request=request;

        }

        //对getParameter增强

        public String getParameter(String name){

            String parameter=request.getParameter(name);//乱码

            try {

                parameter=new String(parameter.getBytes("iso8859-1"),"UTF-8");

            } catch (UnsupportedEncodingException e) {

                // TODO Auto-generated catch block

                e.printStackTrace();

            }

            return parameter;

        }

    }

}

4.编写web.xml

<filter>

    <filter-name>encodeFilter</filter-name>

    <filter-class>cn.cc.filter.EncodingFilter </filter-class> 

</filter> 

<filter-mapping> 

　　<filter-name>encodeFilter</filter-name>

　　 <url-pattern>/*</url-pattern> 

</filter-mapping>

5.控制台分别输出    处理前和处理后的输出

通过过滤器和增强request对象解决get提交请求服务器端乱码。