ajax 请求在IE6,IE7与FIREFOX和IE8中的区别

最近用Ajax来做页面异步请求，在是在IE8和firefox中没错误，IE6、7都出现了错误，经过两天的奋斗最终确认是因为url长度的问题，由于在页面中拼了一个很长的字符串,并将此字符串当作get请求传送,而url长度很大有超过4000个字节，而ie6、7不支持这样长的url，ie8是可以，这样就导致了无论如何都提交不了

最好的解决方法就是使用POST请求!

代理类如下:

/*
 * 文件名：proxyHandler.java
 * 描述：
 * 修改人：ROGER
 * 修改时间：Aug 19, 2011
 * 跟踪单号：
 * 修改单号：
 * 修改内容：
 */

package com.huawei.bjwxcs.common.proxy;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;

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

import org.apache.http.protocol.HTTP;
import org.apache.log4j.Logger;

public class ProxyHandler extends HttpServlet {

  private static final long serialVersionUID = 1L;
  
  private final Logger logger = Logger.getLogger(getClass());

  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
    //System.out.println("------*****---------------------doGet start----------------------------------");
    logger.info("------*****---------------------doGet start----------------------------------");
    //System.out.println("ProxyHandler noSecurityRequest 请求类型: GET");
    String url0 = "";
    OutputStream out = null;
    HttpURLConnection conn = null;
    try {
     url0 = req.getQueryString();
     if (url0.startsWith("url=")) {
      url0 = url0.substring(4);
     }
     if(url0.indexOf("requestTime")!=-1) {
      url0 = url0.split("requestTime")[0];
      url0 = url0.substring(0, url0.length()-1);
     }
     
     URL url = new URL(url0);
     conn = (HttpURLConnection)url.openConnection();
 
     conn.setRequestMethod("GET");
     //urlConnection.setRequestMethod("POST");
     
     conn.setDoOutput(true);   
     conn.setDoInput(true);   
     conn.setUseCaches(false);
     //conn.setConnectTimeout(3000);
     out = resp.getOutputStream();
     resp.setContentType("text/plain; charset=UTF-8");
     
     BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream(), HTTP.UTF_8));
     BufferedWriter wd = new BufferedWriter(new OutputStreamWriter(resp.getOutputStream(), HTTP.UTF_8));
     
     String tempLine = rd.readLine();
     
     StringBuffer scenarioSb = new StringBuffer();
          
          while (tempLine != null){
              wd.write(tempLine);
             scenarioSb.append(tempLine);
              tempLine = rd.readLine();
          }
          
          wd.flush();
          System.out.println("请求地址: "+url0+"请求成功!");
          logger.info("请求成功地址: "+url0 +"\\r\\n");
          logger.info("返回结果: "+scenarioSb.toString());
          //System.out.println("返回结果:"+scenarioSb.toString());
    } catch (Exception e) {
     logger.info("请求出错地址: "+url0+"错误内容:"+e.getMessage());
    } finally {
      try {
       if(out!=null) {
        out.close();
       }
       if(conn!=null) {
        conn.disconnect();
       }
      } catch (Exception e) {
          e.printStackTrace();
      }
    }
    logger.info("------*****---------------------doGet end----------------------------------");
    //System.out.println("------*****---------------------doGet end----------------------------------");
  } 
  
  public void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
   logger.info("------*****---------------------doPost start----------------------------------");
   String reStr = null;
    try {
     BufferedReader reader = new BufferedReader(new InputStreamReader(req.getInputStream(), HTTP.UTF_8));
     StringBuffer reSb = new StringBuffer();
     String tempStr = reader.readLine();
     while (tempStr != null){
      reSb.append(tempStr);
      tempStr = reader.readLine();
          }
    reStr = reSb.toString();
    } catch (Exception ex) {
     logger.error("解析客户端发送的请求错误!/n"+ex);
    }
   
    String url0 = "";
    OutputStream out = null;
    HttpURLConnection conn = null;
    try {
     url0 = req.getQueryString();
     if (url0.startsWith("url=")) {
      url0 = url0.substring(4);
     }
     if(url0.indexOf("requestTime")!=-1) {
       url0 = url0.split("requestTime")[0];
       url0 = url0.substring(0, url0.length()-1);
     }
     if(reStr!=null){
      url0 = url0 + reStr;
     }
     URL url = new URL(url0);
     conn = (HttpURLConnection)url.openConnection();
 
     conn.setRequestMethod("GET");
     //urlConnection.setRequestMethod("POST");
     
     conn.setDoOutput(true);   
     conn.setDoInput(true);   
     conn.setUseCaches(false);
     //conn.setConnectTimeout(3000);
     out = resp.getOutputStream();
     resp.setContentType("text/plain; charset=UTF-8");
     
     BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream(), HTTP.UTF_8));
     BufferedWriter wd = new BufferedWriter(new OutputStreamWriter(resp.getOutputStream(), HTTP.UTF_8));
     
     String tempLine = rd.readLine();
     
     StringBuffer scenarioSb = new StringBuffer();
          
          while (tempLine != null){
              wd.write(tempLine);
             scenarioSb.append(tempLine);
              tempLine = rd.readLine();
          }
          
          wd.flush();
          System.out.println("请求地址: "+url0+"请求成功!");
          logger.info("请求成功地址: "+url0 +"\\r\\n");
          logger.info("返回结果: "+scenarioSb.toString());
          //System.out.println("返回结果:"+scenarioSb.toString());
    } catch (Exception e) {
     logger.info("请求出错地址: "+url0+"错误内容:"+e.getMessage());
    } finally {
      try {
       if(out!=null) {
        out.close();
       }
       if(conn!=null) {
        conn.disconnect();
       }
      } catch (Exception e) {
          e.printStackTrace();
      }
    }
    logger.info("------*****---------------------doPost end----------------------------------");
  }
}