hadoop调用HDFS java api实现在HDFS上创建文件夹

public static void main(String[] args) throws IOException {
        System.setProperty("HADOOP_USER_NAME","root");
        if(args.length==0){
            System.out.println("ERR!创建文件夹失败！请传入一个路径参数作为将要创建的文件夹");
            return;
        }
        String targetDir=args[0];
        //创建一个配置对象
        Configuration conf = new Configuration() ;
        //2设置fs.defaultFS 属性，目的是创建一个DistributedFileSystem对象
        conf.set("fs.defaultFS","hdfs://192.168.58.3:9000");
        //获取一个FileSystem对象（文件系统对象）
        FileSystem fs=FileSystem.get(conf);
        boolean mkdirs= fs.mkdirs(new Path(targetDir));
        if(mkdirs){
            System.out.println("成功在HDFS上创建"+targetDir);
        }
        fs.close();
    }

4.对JAVA程序传入参数后运行程序

5.将项目打包成可运行的jar包，并上传到服务器

5.1、IDEA开发hadoop项目打包

1.右击项目名称，选择Open Module Settings



2.选择Artifacts，点击中间绿色的+号，选择JAR,再选择第二个选项

3.点击Main Class右边的小方块选择主类，下一个选项如果要打成一个压缩包选择第一个，如果其他依赖包要分开放也就是最后是多个jar包选择第二个选项。我选第一个，然后点击OK



4.勾选include in project build，点击+和-号添加最后jar包内的其他jar包，主要是将项目依赖的jar包导入，如果一开始配置好了，直接点OK就行。



5.然后点击Build按钮，选择Build Artifacts...



6.出现以下选择框，第一次使用选择Build，非第一次选Rebuild



7.Build完之后多出了out目录与target目录，接着就可以去本地out目录下找已经完成的jar包

5.2在CMD.exe验证jar包是否可以运行

5.3修改之前写的myhdfs脚本(我之前的myhdfs脚本是有内容的），脚本内部调用java命令运行能创建文件夹的jar包，从而实现在HDFS上创建文件夹

5.4在服务器上运行jar包

三、可能出现的问题

在编写java的时候出现以下报错

Exception in thread "main" org.apache.hadoop.security.AccessControlException: Permission denied: user=·봺Ï, access=WRITE, inode="/user/·봺Ï/cc.txt":root:supergroup:drwxr-xr-x
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:319)
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:292)
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:213)
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:190)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkPermission(FSDirectory.java:1698)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkPermission(FSDirectory.java:1682)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkAncestorAccess(FSDirectory.java:1665)
	at org.apache.hadoop.hdfs.server.namenode.FSDirMkdirOp.mkdirs(FSDirMkdirOp.java:71)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirs(FSNamesystem.java:3900)
	at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.mkdirs(NameNodeRpcServer.java:978)
	at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.mkdirs(ClientNamenodeProtocolServerSideTranslatorPB.java:622)
	at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
	at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:616)
	at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:969)
	at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
	at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2045)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:422)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
	at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2043)

	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
	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.DFSClient.primitiveMkdir(DFSClient.java:3010)
	at org.apache.hadoop.hdfs.DFSClient.mkdirs(DFSClient.java:2978)
	at org.apache.hadoop.hdfs.DistributedFileSystem$21.doCall(DistributedFileSystem.java:1047)
	at org.apache.hadoop.hdfs.DistributedFileSystem$21.doCall(DistributedFileSystem.java:1043)
	at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
	at org.apache.hadoop.hdfs.DistributedFileSystem.mkdirsInternal(DistributedFileSystem.java:1043)
	at org.apache.hadoop.hdfs.DistributedFileSystem.mkdirs(DistributedFileSystem.java:1036)
	at org.apache.hadoop.fs.FileSystem.mkdirs(FileSystem.java:1877)
	at lzzy.Mkdir.main(Mkdir.java:23)
Caused by: org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.security.AccessControlException): Permission denied: user=·봺Ï, access=WRITE, inode="/user/·봺Ï/cc.txt":root:supergroup:drwxr-xr-x
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:319)
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:292)
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:213)
	at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:190)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkPermission(FSDirectory.java:1698)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkPermission(FSDirectory.java:1682)
	at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkAncestorAccess(FSDirectory.java:1665)
	at org.apache.hadoop.hdfs.server.namenode.FSDirMkdirOp.mkdirs(FSDirMkdirOp.java:71)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirs(FSNamesystem.java:3900)
	at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.mkdirs(NameNodeRpcServer.java:978)
	at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.mkdirs(ClientNamenodeProtocolServerSideTranslatorPB.java:622)
	at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
	at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:616)
	at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:969)
	at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
	at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2045)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.Subject.doAs(Subject.java:422)
	at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
	at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2043)

	at org.apache.hadoop.ipc.Client.call(Client.java:1476)
	at org.apache.hadoop.ipc.Client.call(Client.java:1407)
	at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:229)
	at com.sun.proxy.$Proxy7.mkdirs(Unknown Source)
	at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.mkdirs(ClientNamenodeProtocolTranslatorPB.java:558)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	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.$Proxy8.mkdirs(Unknown Source)
	at org.apache.hadoop.hdfs.DFSClient.primitiveMkdir(DFSClient.java:3008)
	... 8 more

Process finished with exit code 1

百度了一下这个问题说是权限问题，操作hdfs的用户不是集群上规定的用户，而且不存在 supergroup组内

解决方法：

我是在代码里添加

System.setProperty(“HADOOP_USER_NAME”,“root”)