我正在使用EWS Java API 1.1.5 ，我正在尝试将服务绑定到收件箱文件夹，如下所示：
ExchangeService service = new ExchangeService();
ExchangeCredentials credentials = new WebCredentials(email, password);
service.setCredentials(credentials);
service.setUrl(new java.net.URI("https://" + host
+ "/EWS/Exchange.asmx"));
Folder inbox = Folder.bind(service, WellKnownFolderName.Inbox);
我从jsp页面调用上面的代码。
但我得到NullPointerException：
java.lang.NullPointerException
at org.apache.commons.httpclient.HttpMethodBase.getStatusCode(HttpMethodBase.java:570)
at microsoft.exchange.webservices.data.HttpClientWebRequest.getResponseCode(Unknown Source)
at microsoft.exchange.webservices.data.ServiceRequestBase.validateAndEmitRequest(Unknown Source)
at microsoft.exchange.webservices.data.SimpleServiceRequestBase.internalExecute(Unknown Source)
at microsoft.exchange.webservices.data.MultiResponseServiceRequest.execute(Unknown Source)
at microsoft.exchange.webservices.data.ExchangeService.bindToFolder(Unknown Source)
at microsoft.exchange.webservices.data.ExchangeService.bindToFolder(Unknown Source)
at microsoft.exchange.webservices.data.Folder.bind(Unknown Source)
at microsoft.exchange.webservices.data.Folder.bind(Unknown Source)
at com.xeno.phonesuite.web.Mail.Mail.readInbox(Mail.java:49)
at org.apache.jsp.mail.inbox_jsp._jspService(inbox_jsp.java:79)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1002)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
我正在使用commons-httpclient 3.1。
从在 tomcat 7 上运行的 Web 项目运行代码时会发生此异常，但从桌面应用程序运行代码时它工作正常。
更新：
1- httpclient 异常前调试：
2012-11-07/16:37:32.425 [http-bio-8080-exec-2] DEBUG Set parameter http.auth.scheme-priority = [NTLM, Basic, Digest]
2012-11-07/16:37:32.425 [http-bio-8080-exec-2] DEBUG enter HttpState.setCredentials(AuthScope, Credentials)
2012-11-07/16:37:32.425 [http-bio-8080-exec-2] DEBUG Set parameter http.socket.timeout = 100000
2012-11-07/16:37:32.425 [http-bio-8080-exec-2] DEBUG Set parameter http.connection.timeout = 100000
2012-11-07/16:37:32.425 [http-bio-8080-exec-2] DEBUG enter PostMethod.clearRequestBody()
2012-11-07/16:37:32.425 [http-bio-8080-exec-2] DEBUG enter EntityEnclosingMethod.clearRequestBody()
2-异常前的 EWS 跟踪：
<Trace Tag="EwsRequestHttpHeaders" Tid="33" Time="2012-11-07 15:14:24Z">
POST /EWS/Exchange.asmx HTTP/1.1
Content-type : text/xml; charset=utf-8
Accept-Encoding : gzip,deflate
Keep-Alive : 300
User-Agent : ExchangeServicesClient/0.0.0.0
Connection : Keep-Alive
Accept : text/xml
</Trace>
并且它应该发送以下请求：
<Trace Tag="EwsRequest" Tid="1" Time="2012-11-07 15:18:19Z">
<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:m="http://schemas.microsoft.com/exchange/services/2006/messages" xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types"><soap:Header><t:RequestServerVersion Version="Exchange2010_SP1"></t:RequestServerVersion></soap:Header><soap:Body><m:FindItem Traversal="Shallow"><m:ItemShape><t:BaseShape>AllProperties</t:BaseShape></m:ItemShape><m:IndexedPageItemView MaxEntriesReturned="5" Offset="0" BasePoint="Beginning"></m:IndexedPageItemView><m:ParentFolderIds><t:DistinguishedFolderId Id="inbox"></t:DistinguishedFolderId></m:ParentFolderIds></m:FindItem></soap:Body></soap:Envelope>
</Trace>
但它没有，而是抛出异常。
UPDATE2：忘了提到我正在使用 Cisco jtapi 6.1 库来处理 IP 电话，谷歌搜索后我发现最新版本的 jtapi 解决了以下问题：
CSCtz31973 : Ews request printed is Null in case of StreamingSubscriptionRequest
我的理解是 EWS 请求为空（无法发送 microsoft webservices 请求），所以我将更新 jtapi 库并试一试。
请告知如何解决它。