上传时报错网络连接错误详细信息null

我使用OSSObjectSample中的demo示例，做上传时报错：
Exception in thread "main" com.aliyun.openservices.ClientException: 网络连接错误，详细信息：null
    at com.aliyun.common.comm.ServiceClient.sendRequestImpl(Unknown Source)
    at com.aliyun.common.comm.ServiceClient.sendRequest(Unknown Source)
    at com.aliyun.openservices.oss.internal.OSSOperation.request(Unknown Source)
    at com.aliyun.openservices.oss.internal.OSSObjectOperation.invoke(Unknown Source)
    at com.aliyun.openservices.oss.internal.OSSObjectOperation.putObject(Unknown Source)
    at com.aliyun.openservices.oss.OSSClient.putObject(Unknown Source)
    at com.aliyun.openservices.oss.samples.UploadFile.main(UploadFile.java:33)
Caused by: org.apache.http.client.ClientProtocolException
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:822)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:754)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:732)
    at com.aliyun.common.comm.DefaultServiceClient.sendRequestCore(Unknown Source)
    ... 7 more

下载时没有任何问题，可以下载。不知道是什么原因。