【现象】
在ajax通过web代理跨域访问时，http第一次登陆时正常，但是第二次再下发其他命令的时候总是返回 java.net.SocketTimeoutException: Read timed out 。
【定位思路】
第一次登陆正常，第二次再访问就不行，说明大多数是和cookie相关。页面在登陆的时候设置cookie是成功的，那么大部分的原因应该是在web代理部分cookie的传输有问题了。仔细看了代理部分的代码，发现web代理部分建立新的http请求的时候，并没有添加cookie。然后上网查找cookie的获得和添加方式。添加上就可以了。
【前台页面代码】
登陆代码：
function DoLogin()
{
m_szUserPwdValue = Base64.encode("admin" + ":" + "12345");
$.ajax({
type: "GET",
url: m_lHttp + m_szHostName + ":" + m_lHttpPort + "/onlineObservationSystem/PSIA/Custom/SelfExt/userCheck",
async: true,
timeout: 15000,
beforeSend: function(xhr) {
xhr.setRequestHeader("If-Modified-Since", "0");
xhr.setRequestHeader("Authorization", "Basic " + m_szUserPwdValue);
},
success: function(xmlDoc, textStatus, xhr)
{
alert("login success");
if("200" == xhr.status)
{
var szUrl = decodeURI(document.URL);
if(szUrl.indexOf("?page=") != -1)
{
var szPage = szUrl.substring(szUrl.indexOf("page=") + 5, szUrl.indexOf("¶ms="));
if(szPage.indexOf(".asp") == -1)
{
szPage = szPage.concat(".asp");
}
var szParam = szUrl.substring(szUrl.indexOf("¶ms=") + 8, szUrl.length);
$.cookie('page',szPage+"?"+szParam+"%1");
}
else
{
$.cookie('page',null);
}
//登陆的时候在这里添加cookie
$.cookie('userInfo'+'80',m_szUserPwdValue==""?Base64.encode("anonymous:\177\177\177\177\177\177"):m_szUserPwdValue);
//window.location.href = "IEfile/doc/page/main.asp";
}
else
{
if(!$('#UserName').prop("disabled")) {
$('#UserName').focus();
}
$('#UserName').val('');
$('#Password').val('');
alert(translator.translateNode(g_lxdLogin, 'LoginTips4'));
}
},
error: function(xhr, textStatus, errorThrown)
{
alert("login error = " + textStatus);
if("timeout" == textStatus)
{
alert(translator.translateNode(g_lxdLogin, 'ConnectTimeoutTips'));
}
else
{
alert(translator.translateNode(g_lxdLogin, 'NetworkErrorTips'));
}
}
});
}
第二次访问的代码：
function GetPatrolsCab() {
$.ajax({
type: "GET",
url: m_lHttp + m_szHostName + ":" + m_lHttpPort + "/onlineObservationSystem/PSIA/PTZ/channels/1/patrols",
async: true,
timeout: 15000,
beforeSend: function(xhr) {
xhr.setRequestHeader("If-Modified-Since", "0");
xhr.setRequestHeader("Authorization", "Basic " + m_szUserPwdValue);
},
success: function(xmlDoc, textStatus, xhr) {
var iLen = $(xmlDoc).find('PTZPatrol').length;
if(0 == iLen) {
alert("get path success,but iLen=0");
//m_oPtzTabs.hideTab(1);
return;
}
$("#selectPatrol").empty();
var szName = parent.translator.translateNode(g_lxdPreview, 'laTrack');
for(var i = 0; i < iLen; i++) {
if (i < 9) {
$("<option value='"+ (i+1) +"'>"+szName+" 0"+(i+1)+"</option>").appendTo("#selectPatrol");
} else {
$("<option value='"+ (i+1) +"'>"+szName+" "+(i+1)+"</option>").appendTo("#selectPatrol");
}
}
$("#selectPatrol").unbind().bind("change",function() {
GetPatrol(this.value);
});
GetPatrolsDelayCab();
},
error: function(XMLHttpRequest, textStatus, errorThrown) {
alert("get path error");
//m_oPtzTabs.hideTab(1);
}
});
}
【web代理代码，就是servlet端代码】
package com.boomdts.weather_monitor.servlet.video; import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.util.List; import javax.servlet.*;
import javax.servlet.http.*; public class psiaFilter implements javax.servlet.Filter { public void destroy() {
}
//char数组转换成byte数组
private byte[] getBytes (char[] chars) {
Charset cs = Charset.forName ("UTF-8");
CharBuffer cb = CharBuffer.allocate (chars.length);
cb.put (chars);
cb.flip ();
ByteBuffer bb = cs.encode (cb);
return bb.array();
}
//byte数组转换成char数组
private char[] getChars (byte[] bytes) {
Charset cs = Charset.forName ("UTF-8");
ByteBuffer bb = ByteBuffer.allocate (bytes.length);
bb.put (bytes);
bb.flip ();
CharBuffer cb = cs.decode (bb);
System.out.println("in size=" + bytes.length + "out size = " + cb.array().length);
return cb.array();
} public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException { //根据当前请求内容获得请求的各个参数
HttpServletRequest req = (HttpServletRequest)(request);
String uri = req.getRequestURI();
uri = uri.substring(24);//删除当前项目名称的字符串
String Auth = req.getHeader("Authorization");
String method = req.getMethod();
Cookie[] cookies = req.getCookies();//取得cookie，这个原来是没有添加的 HttpServletResponse res = (HttpServletResponse)(response); //发起一个新的http连接，设置新建连接的参数(就是把刚才请求的参数设置成新的连接的参数)。
String url= "http://172.16.8.178" + uri;
//System.out.println("url = " + url);
URL theURL = new URL(url);
HttpURLConnection urlConnection = (HttpURLConnection)theURL.openConnection(); urlConnection.setReadTimeout(500000);
System.out.println("method = " + method);
urlConnection.setRequestMethod(method);
urlConnection.setRequestProperty("If-Modified-Since", "0");
urlConnection.setRequestProperty("Authorization", Auth);
for(Cookie c:cookies){
urlConnection.addRequestProperty("Cookie", c.getName() + "=" + c.getValue());//添加cookie，这个原来是没有添加的
//System.out.println("cookie name=" + c.getName() +"; value=" + c.getValue());
}
urlConnection.connect(); PrintWriter out = res.getWriter();
//取得http连接响应数据，并把响应数据返回前台页面
if (urlConnection.getResponseCode() == 200)
{
System.out.println("urlConnection return success");
//解析返回信息
InputStream in = urlConnection.getInputStream(); int c;
while((c = in.read()) != -1)
out.write(c); } else {
System.out.println("error! urlConnection.getResponseCode() = " + urlConnection.getResponseCode());
} } public void init(FilterConfig arg0) throws ServletException {
} }
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