2007-10-15

Java的AJAX请求中文编码方法

关键字: AJAX 中文乱码 乱码 编码 中文编码
这里的方案是页面(page)是基于GBK(gb2312) 的编码格式

AJAX的中文情况,默认情况下,tomcat和weblogic的get和post请求的编码方案都不一样,不过前提都是要设置request.setCharactorEncoding("UTF-8")如下面代码中,get方案是很烦琐的那种将得到的参数重新编码来实现的|new String(request.getParameter("para name").getBytes("encoding name"))|而post方案是比较简单而方便的,也提倡使用这种方式,因为可以基于filter来管理编码
tomcat可以通过设置在server.xml里的Connector元素下设置URIencoding="gbk"参数来让get使用post的方案(即get和post都使用request.setCharactorEncoding("UTF-8"),request.getParameter("para name") )具体设置参考http://www.javaeye.com/topic/131542,不过在weblogic下无解(我个人还没发现如何实现),weblogic好像在解析get参数后自己又用什么编码格式包装过......其实AJAX get根本没有普通请求get请求作为标签的作用,我们完全可以不使用get,而只使用post

测试用的jsp和servlet在下面,丢到一个项目里,在web.xml里配置servlet后运行可以看到效果,servlet的url-pattern是这个<url-pattern>/GetAndPostExample</url-pattern>

getAndPostExample.jsp 
<%@ page language="java" import="java.util.Date"  contentType="text/html; charset=gbk"%>
<html>
	<head>
		<title>发送带参数的信息到服务器，以及get,post的区别</title>
		<script type="text/javascript">
			var xmlHttp;			
			function show()
				{
				document.getElementById("show").value=document.getElementById("firstName").value;
				}
			function createXMLHttpRequest()
				{
				if (window.ActiveXObject)
					xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
				else if (window.XMLHttpRequest)
					xmlHttp = new XMLhttpRequest();
				}
			
			function createQueryString()
				{
				var firstName = document.getElementById("firstName").value;
				var secondName = document.getElementById("secondName").value;
				var birthday = document.getElementById("birthday").value;
				
				var queryString = "firstName="+firstName+"&secondName="+secondName
												+"&birthday="+birthday;
				return queryString;
				}
			
			function doRequestUsingGET()
				{
				createXMLHttpRequest();
				show();
				var queryString = "GetAndPostExample?";
				queryString = queryString + createQueryString()
										+ "&timeStamep=" + new Date().getTime();
				xmlHttp.onreadystatechange = handleStateChange;
				xmlHttp.open("GET",queryString,true);
                                    xmlHttp.setRequestHeader("RequestType","ajax");
				xmlHttp.send(null);
				//alert(queryString);
				}
				
			function doRequestUsingPOST()
				{
				createXMLHttpRequest();
				show();		
				var url = "GetAndPostExample"
				var queryString = createQueryString()+ "&timeStamp="+ new Date().getTime();			
				xmlHttp.open("POST",url,true);
				xmlHttp.onreadystatechange = handleStateChange;
				xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded;");
                                     //设置报头,说明此请求是ajax请求
                                     xmlHttp.setRequestHeader("RequestType","ajax");
				xmlHttp.send(queryString);
				}
				
			function handleStateChange()
				{
				if (xmlHttp.readyState == 4)
					{
					if (xmlHttp.status == 200)
						parseResults();
					}
				}
			
			function parseResults()
				{
				var responseDiv = document.getElementById("serverResponse");
				if (responseDiv.hasChildNodes())
					{
					responseDiv.removeChild(responseDiv.childNodes[0]);
					}
				var responseText = document.createTextNode(xmlHttp.responseText);
				responseDiv.appendChild(responseText);
				}
			
		</script>
	</head>
	<body>
		<h1>输入你的姓，名，生日日期</h1>
		<br>
		
			<table>
				<tr>
					<td>
						姓：
					</td>
					<td>
						<input type="text" name="firstName" id="firstName" value="羽飞">
					</td>
				</tr>
					<td>
						名：
					</td>
					<td>
						<input type="text" name="secondName" id="secondName" value="翼">
					</td>
				<tr>
				</tr>
				<tr>
					<td>
						生日：
					</td>
					<td>
						<input type="text" name="birthday" id="birthday" value="五月">
					</td>
					<td>
						<input type="text" name="show" id="show">
					</td>
				</tr>
			</table>
		<form action="#">
			<input type="button" value="使用GET提交" onclick="doRequestUsingGET();">
			<br>
			<input type="button" value="使用POST提交" onclick="doRequestUsingPOST();">
		</form>
		<br>
		<br>		
		<h2>服务器返回信息：</h2>		
		<div id="serverResponse">
		</div>
	</body>
</html>


GetAndPostExample.java 
package yufei;

import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class GetAndPostExample extends HttpServlet
	{
		protected void processRequest(HttpServletRequest request,
				HttpServletResponse response, String method1)
				throws ServletException,IOException
				{
				//设置文本类型(content type)
				response.setContentType("text/xml");
                                     //设置文本类型的编码格式
				response.setCharacterEncoding("GBK");
				response.setHeader("Cache-Control","no-cache");
				
				String firstName =null;
				String secondName = null;
				String birthday = null;
                                    //无论是get还是post,都要使用下面这句
                                    request.setCharacterEncoding("UTF-8");
				if (method1.equals("GET"))
				{			     
				 firstName = new String(request.getParameter("firstName").getBytes("ISO8859-1"));
				 secondName = new String(request.getParameter("secondName").getBytes("ISO8859-1"));
				 birthday = new String(request.getParameter("birthday").getBytes("ISO8859-1"));
				}
				else if (method1.equals("POST"))
				{				 			 firstName = request.getParameter("firstName");
				 secondName = request.getParameter("secondName");
				 birthday = request.getParameter("birthday");
				}	
				String responseText = "Hello " + firstName + " " + secondName
								+ " 你的生日是 " + birthday + " " + "(method: " + method1 + ")";				
				PrintWriter out = response.getWriter();
				out.println(responseText);
				
				out.close();
				}
		protected void doGet(HttpServletRequest request,
				HttpServletResponse response)
				throws ServletException,IOException
				{
				processRequest(request,response,"GET");
				}
		protected void doPost(HttpServletRequest request,
				HttpServletResponse response)
				throws ServletException,IOException
				{
				processRequest(request,response,"POST");
				}
	}


-
-

当我们的ajax请求只使用post(tomcat下可以实现get和post同样方案)请求时,我们可以使用过滤器来实现其编码设置,就可以把servlet中的request.setCharactorEncoding提出来,去掉servlet里的request.setCharactorEncoding("encoding name"),加入下面的过滤器
根据fins大大的指导,将过滤器重写为可以区分普通请求和ajax请求的样式了(ajax请求中设置了header)

SetCharacterEncodingFilter.java 
package yufei;

import java.io.IOException;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.Filter;
import javax.servlet.http.HttpServletRequest;

public class CharactorEncodingFilter implements Filter
	{
	public CharactorEncodingFilter()
		{
		super();
		}
	private FilterConfig filterConfig;
	private String ajaxEncoding = "UTF-8";
	private String commonEncoding;
	protected boolean ignore = true;
	public void init(FilterConfig filterConfig) throws ServletException
		{
		this.filterConfig = filterConfig;
		commonEncoding = filterConfig.getInitParameter("CommonRequestEncoding");
		String value = filterConfig.getInitParameter("ignore");
		if (value == null)
			this.ignore = true;
		else if (value.equalsIgnoreCase("true"))
			this.ignore = true;
		else if (value.equalsIgnoreCase("yes"))
			this.ignore = true;
		else
			this.ignore = false;
		}

	public void doFilter(ServletRequest req, ServletResponse res,
		FilterChain filterChain)

		{
		try
			{
			HttpServletRequest request = (HttpServletRequest) req;
			if (ignore || (request.getCharacterEncoding() == null))
				{
				if (request.getHeader("RequestType") != null
					&& request.getHeader("RequestType")
						.equalsIgnoreCase("ajax"))
					{
					request.setCharacterEncoding(ajaxEncoding);
					}
				else if (commonEncoding != null)
					{
					request.setCharacterEncoding(commonEncoding);
					}
				else
					{
					request.setCharacterEncoding("UTF-8");
					}
				}
			filterChain.doFilter(req, res);
			}
		catch (IOException e)
			{
			e.printStackTrace();
			}
		catch (ServletException e)
			{
			e.printStackTrace();
			}
		}
	public void destroy()
		{
		this.commonEncoding = null;
		this.filterConfig = null;
		}
	}


web.xml加入如下过滤器配置 
	<filter>
		<filter-name>CharactorEncoding</filter-name>
		<filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
                  <!-- 设置编码格式到initparameter里去 -->
		<init-param>
			<param-name>CommonRequestEncoding</param-name>
			<param-value>GBK</param-value>
		</init-param>		
	</filter>
	<filter-mapping>
		<filter-name>CharactorEncoding</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
评论
yufei 2007-10-15
谢谢楼上大大的提醒,标题已经改了,楼上设置header的方法我拿去了,本来我是要连同和普通请求共存一起写的,不过发觉有不少问题要探讨,所以临时决定分开发的,不过看来没必要了

最早我是决定使用多传一个参数来区分ajax和普通请求,结果发现request.getParameter()以后再设置request.setCharactorEncoding()就不会正确(tomcat不正确,weblogic正确..)看了下j2ee-api,发现setCharactorEncoding方法的说明有以下一段This method must be called prior to reading request parameters or reading input using getReader(),看来读取header不会有影响?
后来使用了双过滤器解决了问题,不过和设置header比起来麻烦了不少,马上去试验

......
......

测试OK,看来使用request.getHeader()不会影响request.setCharactorEncoding()
编辑了原文,让其可以根据header参数来区分ajax请求和普通请求了
fins 2007-10-15
回楼主 你这不能叫方案 只能叫"解决ajax乱码的基本方法"

所谓方案应该更系统 更周全.

我问个问题, 如果不是用UTF-8的系统怎么办?

正确的"方案"应该是 后台编码过滤器可以自动分析请求是 ajax还是普通请求.
普通请求则使用 web.xml里配置的编码
ajax请求则使用utf-8

判断的方式很多 常见的也是最好的方案是 在ajax请求里设置 header信息
告诉服务器这是一个ajax请求, 服务器在编码前 从header里取得信息 判断后编码
yufei 2007-10-15
UTF-8我出现过乱码....页面里
UTF-8在某些情况还是会有乱码...虽然几率不高...
我用GB18030也出现过乱码(新国标码,可能支持不够吧),页面里
mvmouse 2007-10-15
不用2312，全部页面都用utf8即可
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