log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).

log4j:WARN Please initialize the log4j system properly.

log4j:WARN See for more info.

Exception in thread "main" java.lang.IllegalArgumentException: Wrong FS: hdfs://sandbox.hortonworks.com:8020/user/testdir, expected: file:///

    at org.apache.hadoop.fs.FileSystem.checkPath(FileSystem.java:645)

    at org.apache.hadoop.fs.RawLocalFileSystem.pathToFile(RawLocalFileSystem.java:80)

    at org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:423)

    at org.apache.hadoop.fs.ChecksumFileSystem.mkdirs(ChecksumFileSystem.java:590)

    at com.hdfs.directory.CreateDir.main(CreateDir.java:19)

在本机运行是会出现上面的错误，改成下面的代码：

package com.hdfs.directory;import java.io.IOException;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.Path;public class CreateDir {    /**     * @param args     * @throws IOException      */    public static void main(String[] args) throws IOException {        // TODO Auto-generated method stub        Configuration conf=new Configuration();        Path newPath = new Path("hdfs://sandbox.hortonworks.com:8020/user/testdir");        //FileSystem fs=FileSystem.get(conf);        FileSystem fs = newPath.getFileSystem(conf);        fs.mkdirs(newPath);        fs.close();//        FileStatus fileStatus=fs.getFileStatus(new Path("/user/long1657/20130908"));            }}

或者hadoop相关的配置信息，放在工程目录下：

 

执行上面的代码后：/user/testdir目录被成功删除:

 

在将hadoop相关的配置文件添加到工程中后，用下面的代码就可以成功创建文件夹：

package com.hdfs.directory;import java.io.IOException;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.Path;public class CreateDirWithConf {    /**     * @param args     * @throws IOException      */    public static void main(String[] args) throws IOException {        // TODO Auto-generated method stub        Configuration conf=new Configuration();            FileSystem fs=FileSystem.get(conf);        fs.mkdirs(new Path("hdfs://sandbox.hortonworks.com:8020/user/testdir"));        fs.close();//        FileStatus fileStatus=fs.getFileStatus(new Path("/user/long1657/20130908"));            }}