我正试图使用命令行中的webhdfs从cdh5机器打开cdh4集群上的hdfs文件，如下所示：

curl -i -L "http://namenodeIpofCDH4:50070/webhdfs/v1/user/quad/source/JSONML.java?user.name=quad&op=OPEN"

即使文件jsonml.java存在于namenode和datanode中提到的路径中，并且其跟踪如下，我也会得到“file not found exception”：

HTTP/1.1 307 TEMPORARY_REDIRECT
Cache-Control: no-cache
Expires: Thu, 01-Jan-1970 00:00:00 GMT
Date: Mon, 22 Feb 2016 13:25:35 GMT
Pragma: no-cache
Date: Mon, 22 Feb 2016 13:25:35 GMT
Pragma: no-cache
Set-Cookie: hadoop.auth="u=quad&p=quad&t=simple&e=1456183535737&s=KdZYcA5iwJeIU2F9ZJfLSaT4qMY=";Path=/
Location: http://n3.quadratics.com:50075/webhdfs/v1/user/quad/source/JSONML.java?op=OPEN&user.name=quad&namenoderpcaddress=n1.quadratics.com:8020&offset=0
Content-Type: application/octet-stream
Content-Length: 0
Server: Jetty(6.1.26.cloudera.4)

HTTP/1.1 404 Not Found
Cache-Control: no-cache
Expires: Mon, 22 Feb 2016 13:26:28 GMT
Date: Mon, 22 Feb 2016 13:26:28 GMT
Pragma: no-cache
Expires: Mon, 22 Feb 2016 13:26:28 GMT
Date: Mon, 22 Feb 2016 13:26:28 GMT
Pragma: no-cache
Content-Type: application/json
Transfer-Encoding: chunked
Server: Jetty(6.1.26.cloudera.4)

{"RemoteException":{"exception":"FileNotFoundException","javaClassName":"java.io.FileNotFoundException","message":"File does not exist: /user/quad/source/JSONML.java\n\tat org.apache.hadoop.hdfs.server.namenode.INodeFile.valueOf(INodeFile.java:66)\n\tat org.apache.hadoop.hdfs.server.namenode.INodeFile.valueOf(INodeFile.java:56)\n\tat org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getBlockLocationsUpdateTimes(FSNamesystem.java:1932)\n\tat org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getBlockLocationsInt(FSNamesystem.java:1873)\n\tat org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getBlockLocations(FSNamesystem.java:1853)\n\tat org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getBlockLocations(FSNamesystem.java:1825)\n\tat org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.getBlockLocations(NameNodeRpcServer.java:559)\n\tat org.apache.hadoop.hdfs.server.namenode.AuthorizationProviderProxyClientProtocol.getBlockLocations(AuthorizationProviderProxyClientProtocol.java:87)\n\tat org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.getBlockLocations(ClientNamenodeProtocolServerSideTranslatorPB.java:363)\n\tat org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)\n\tat org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:619)\n\tat org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1060)\n\tat org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2044)\n\tat org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2040)\n\tat java.security.AccessController.doPrivileged(Native Method)\n\tat javax.security.auth.Subject.doAs(Subject.java:415)\n\tat org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1671)\n\tat org.apache.hadoop.ipc.Server$Handler.run(Server.java:2038)\n"}}

但是当我使用下面的命令时，我没有得到任何错误和上面文件的状态：

curl -i -L http://namenodeIpofCDH4:50070/webhdfs/v1/user/quad/source/JSONML.java?user.name=quad&op=GETFILESTATUS"

我得到的输出响应如下：

HTTP/1.1 200 OK
Cache-Control: no-cache
Expires: Thu, 01-Jan-1970 00:00:00 GMT
Date: Mon, 22 Feb 2016 13:38:48 GMT
Pragma: no-cache
Date: Mon, 22 Feb 2016 13:38:48 GMT
Pragma: no-cache
Set-Cookie: hadoop.auth="u=quad&p=quad&t=simple&e=1456184328134&s=sE6esO8J39O+itl+ggNzX4/WzjQ=";Path=/
Content-Type: application/json
Transfer-Encoding: chunked
Server: Jetty(6.1.26.cloudera.4)

{"FileStatus":{"accessTime":1456147448567,"blockSize":134217728,"group":"quad","length":14849,"modificationTime":1456143798039,"owner":"quad","pathSuffix":"","permission":"644","replication":3,"type":"FILE"}}

任何关于打开一个文件失败的原因的想法，以及如何修复，我们都将不胜感激。