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

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原文地址：https://www.cnblogs.com/benjamin77/p/9238035.html

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

2.创建一个servlet用于获取表单数据 并输出

3.创建过滤器，并增强request对象解决乱码

4.编写web.xml

5.控制台分别输出 处理前和处理后的输出

2.创建一个servlet用于获取表单数据并输出

5.控制台分别输出处理前和处理后的输出