我需要从Java应用程序将文件上传到Web服务。因此我使用Apaches HttpClient。另外我需要通过代理连接。在我的例子中，这是一个带有基本身份验证的squid代理。将来，这可能会更改为使用其他身份验证类型的其他代理。
这是我当前代码的片段：
MultipartEntity entity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);
... //fill entity
CredentialsProvider provider = new MyCredentialsProvider();
HttpRoutePlanner routePlanner = new SystemDefaultRoutePlanner(ProxySelector.getDefault());
CloseableHttpClient client = HttpClients.custom()
.setRoutePlanner(routePlanner)
.setDefaultCredentialsProvider(provider)
.build();
...
HttpPost post = new HttpPost(url);
post.setHeader("Cookie",cookies); //needed for session
post.setEntity(entity);
...
HttpResponse res = client.execute(post);
...
client.close();
MyCredentialsProvider是一个自制类，因为HttpClient的SystemDefaultCredentialsProvider似乎无法按预期工作。它基本上使用java.net.Authenticator从用户请求凭据。
使用此代码似乎一切正常。我可以在Java控制面板中使用我的squid代理集（无身份验证和基本身份验证）上传没有代理集的文件。当我上传一个稍微大一点的文件（大约64kb）时，我才会遇到这个问题。在这种情况下，client.execute（post）在超时运行时出现以下异常：[proxy ip]：[proxy port]无法响应
org.apache.http.NoHttpResponseException: [proxy ip]:[proxy port] failed to respond
at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:143)
at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:57)
at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:261)
at org.apache.http.impl.DefaultBHttpClientConnection.receiveResponseHeader(DefaultBHttpClientConnection.java:165)
at org.apache.http.impl.conn.CPoolProxy.receiveResponseHeader(CPoolProxy.java:167)
at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:272)
at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:124)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:271)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:184)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:88)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:184)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:107)
...
在Wireshark中我可以看到，HttpClient发出两个相同的http post请求。一个没有http标题＆＃34;代理授权＆＃34; n，一个没有＆＃34;代理授权：基本...＆＃34;。第一个获得预期的响应（需要407代理身份验证）。秒请求没有响应。我可以看到两个请求都只包含多部分实体的第一个参数。
我可以用HttpClient 4.2.1重现这种现象。
是否还有人参加过此活动？我想这有事可做，这两个请求都是在一个http连接中进行的。有谁知道如何配置HttpClient或squid代理来使其工作？
感谢您的帮助。
修改 如果我按照http://www.nuxeo.com/blog/using-httpclient-properly-avoid-closewait-tcp-connections/的说明操作，我可以将最大文件大小增加到大约1mb。我在执行请求之前设置了一个http标头：
post.setHeader("Connection", "close");
超过1mb的文件给我以下例外：
java.net.SocketException: Connection reset by peer: socket write error
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(Unknown Source)
at java.net.SocketOutputStream.write(Unknown Source)
at org.apache.http.impl.io.SessionOutputBufferImpl.streamWrite(SessionOutputBufferImpl.java:126)
at org.apache.http.impl.io.SessionOutputBufferImpl.write(SessionOutputBufferImpl.java:162)
at org.apache.http.impl.io.ContentLengthOutputStream.write(ContentLengthOutputStream.java:115)
at org.apache.http.impl.io.ContentLengthOutputStream.write(ContentLengthOutputStream.java:122)
at org.apache.http.entity.mime.content.ByteArrayBody.writeTo(ByteArrayBody.java:97)
at org.apache.http.entity.mime.AbstractMultipartForm.doWriteTo(AbstractMultipartForm.java:134)
at org.apache.http.entity.mime.AbstractMultipartForm.writeTo(AbstractMultipartForm.java:157)
at org.apache.http.entity.mime.MultipartFormEntity.writeTo(MultipartFormEntity.java:113)
at org.apache.http.entity.mime.MultipartEntity.writeTo(MultipartEntity.java:180)
at org.apache.http.impl.DefaultBHttpClientConnection.sendRequestEntity(DefaultBHttpClientConnection.java:158)
at org.apache.http.impl.conn.CPoolProxy.sendRequestEntity(CPoolProxy.java:162)
at org.apache.http.protocol.HttpRequestExecutor.doSendRequest(HttpRequestExecutor.java:237)
at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:122)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:271)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:184)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:88)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:184)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:107)
但这不是解决方案，因为我需要上传更大的文件（可能高达10mb）和多个文件！