Ajax基础+Ajax开发中的编码问题-优快云博客

本文链接：https://blog.youkuaiyun.com/jhlisprimer/article/details/83738263

本文介绍了一个在Servlet开发中常见的编码问题，特别是在不同浏览器下（如IE与火狐）使用不同的字符集时出现的问题。通过一个具体的例子展示了如何正确地设置响应内容类型及字符集以确保跨浏览器的兼容性。

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·-- 首先开发中要注意的一个问题，这个问题困扰我好几个小时，编码问题。

如果在Servlet进行如下设置时：

resp.setContentType("text/xml;charset=UTF-8");
resp.setCharacterEncoding("UTF-8");

IE8和火狐时没有问题的，但是换成如下形式，

resp.setContentType("text/xml;charset=UTF-8");
resp.setCharacterEncoding("GBK");

或者
resp.setContentType("text/xml;charset=GBK");
resp.setCharacterEncoding("GBK");

时，会出现的现象是火狐操作正常，IE操作不正常。原理暂时不清楚，等待高手指点。

1、新建一个Servlet

package com.sunrex.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@SuppressWarnings("serial")
public class AjaxServlet extends HttpServlet {

	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		
		resp.setContentType("text/xml;charset=UTF-8");
		resp.setCharacterEncoding("UTF-8");
		resp.setHeader("Cache-Control", "no-cache");
		StringBuffer sb = new StringBuffer();
		sb.append("<nation>");
			sb.append("<detail>");
				sb.append("<address>").append("中国").append("</address>");
				sb.append("<city>").append("上海").append("</city>");
			sb.append("</detail>");
			
			sb.append("<detail>");
				sb.append("<address>").append("美国").append("</address>");
				sb.append("<city>").append("纽约").append("</city>");
			sb.append("</detail>");
			
			sb.append("<detail>");
				sb.append("<address>").append("日本").append("</address>");
				sb.append("<city>").append("东京").append("</city>");
			sb.append("</detail>");
		sb.append("</nation>");
		System.out.println(sb.toString());
		PrintWriter out = resp.getWriter();
		out.write(sb.toString());
		out.close();
	}
}

2、配置web.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
	xmlns="http://java.sun.com/xml/ns/j2ee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
  <servlet>
  	<servlet-name>ajax</servlet-name>
  	<servlet-class>com.sunrex.servlet.AjaxServlet</servlet-class>
  </servlet>
  <servlet-mapping>
  	<servlet-name>ajax</servlet-name>
  	<url-pattern>/servlet/ajax</url-pattern>
  </servlet-mapping>  
</web-app>

3、jsp文件

<%@ page language="java" contentType="text/html; charset=GB18030"
    pageEncoding="GB18030"%>
<!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=GB18030">
<title>Insert title here</title>
<script type="text/javascript">
	var xmlHttp;
	function createXMLHTTP() {
		if(window.XMLHttpRequest) {
			xmlHttp = new XMLHttpRequest();
		} else if(window.ActiveXObject) {
			xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
		}
	}

	function show() {
		
		createXMLHTTP();
		var url = "servlet/ajax";
		xmlHttp.open("GET", url);
		xmlHttp.onreadystatechange = callback;
		xmlHttp.send(null);
	}
	
	function callback() {
		if(xmlHttp.readyState == 4) {
			if(xmlHttp.status == 200) {
				var xmlText = xmlHttp.responseXML.getElementsByTagName("nation")[0];
				var childrenNodes = xmlText.childNodes;
				var nodeLength = childrenNodes.length;
				var tables = "<table border='1'>";
				for(var i=0; i<nodeLength; i++) {
					var address = childrenNodes[i].childNodes[0].firstChild.nodeValue;
					var city = childrenNodes[i].childNodes[1].firstChild.nodeValue;
					tables = tables + "<tr><td>" + address + "</td>";
					tables = tables +  "<td>" + city +  "</td></tr>";
				}
				tables = tables + "</table>";
				document.getElementById("showContent").innerHTML = tables;
			}
		}
	}
</script>
</head>
<body>
<input type="button" name="button1" value="显示服务器内容" id="button1" onclick="show()">
<br>
<span id="showContent"></span>
</body>
</html>