Exception in thread "main" org.apache.hadoop.security.AccessControlException: Permission denied: user=kandy, access=WRITE, inode="/user/home":root:supergroup:drwxr-xr-x
at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkFsPermission(FSPermissionChecker.java:271) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:257) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:238) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:179) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(FSNamesystem.java:5904) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(FSNamesystem.java:5886) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkAncestorAccess(FSNamesystem.java:5860) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInternal(FSNamesystem.java:2362) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInt(FSNamesystem.java:2315) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:2266) at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.create(NameNodeRpcServer.java:542) at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.create(ClientNamenodeProtocolServerSideTranslatorPB.java:369) at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java) at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:585) at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:928) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2013) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2009) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1614) at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2007)at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:526) at org.apache.hadoop.ipc.RemoteException.instantiateException(RemoteException.java:106) at org.apache.hadoop.ipc.RemoteException.unwrapRemoteException(RemoteException.java:73) at org.apache.hadoop.hdfs.DFSOutputStream.newStreamForCreate(DFSOutputStream.java:1616) at org.apache.hadoop.hdfs.DFSClient.create(DFSClient.java:1488) at org.apache.hadoop.hdfs.DFSClient.create(DFSClient.java:1413) at org.apache.hadoop.hdfs.DistributedFileSystem$6.doCall(DistributedFileSystem.java:387) at org.apache.hadoop.hdfs.DistributedFileSystem$6.doCall(DistributedFileSystem.java:383) at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81) at org.apache.hadoop.hdfs.DistributedFileSystem.create(DistributedFileSystem.java:383) at org.apache.hadoop.hdfs.DistributedFileSystem.create(DistributedFileSystem.java:327) at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:906) at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:887) at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:784) at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:773) at com.my.hadoop.HadoopTest.uploadFile(HadoopTest.java:48) at com.my.hadoop.HadoopTest.main(HadoopTest.java:68) Caused by: org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.security.AccessControlException): Permission denied: user=kandy, access=WRITE, inode="/user/home":root:supergroup:drwxr-xr-x at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkFsPermission(FSPermissionChecker.java:271) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:257) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:238) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:179) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(FSNamesystem.java:5904) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(FSNamesystem.java:5886) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkAncestorAccess(FSNamesystem.java:5860) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInternal(FSNamesystem.java:2362) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInt(FSNamesystem.java:2315) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:2266) at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.create(NameNodeRpcServer.java:542) at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.create(ClientNamenodeProtocolServerSideTranslatorPB.java:369) at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java) at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:585) at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:928) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2013) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2009) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1614) at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2007)at org.apache.hadoop.ipc.Client.call(Client.java:1411)
at org.apache.hadoop.ipc.Client.call(Client.java:1364) at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:206) at com.sun.proxy.$Proxy14.create(Unknown Source) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:187) at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102) at com.sun.proxy.$Proxy14.create(Unknown Source) at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.create(ClientNamenodeProtocolTranslatorPB.java:264) at org.apache.hadoop.hdfs.DFSOutputStream.newStreamForCreate(DFSOutputStream.java:1612) ... 13 more====================================
查找资料并试验了一下，总结了以上问题的三种解决办法：
1、在系统的环境变量或java JVM变量里面添加HADOOP_USER_NAME，这个值具体等于多少看自己的情况，以后会运行HADOOP上的Linux的用户名。（修改完重启eclipse，不然可能不生效）
2、将当前系统的帐号修改为hadoop
3、使用HDFS的命令行接口修改相应目录的权限，hadoop fs -chmod 777 /user/home,后面的/user是要上传文件的路径，不同的情况可能不一样，比如要上传的文件路径为hdfs://namenode/user/xxx.doc，则这样的修改可以，如果要上传的文件路径为hdfs://namenode/java/xxx.doc，则要修改的为hadoop fs -chmod 777 /java或者hadoop fs -chmod 777 /，java的那个需要先在HDFS里面建立Java目录，后面的这个是为根目录调整权限。