伪分布模式下使用java接口，访问hdfs

 package com.bq.pro;

 import java.io.IOException;

 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.util.GenericOptionsParser;
 import org.apache.hadoop.util.Progressable;

 public class MergeFiles {
     @SuppressWarnings("deprecation")
     public static void main(String[] args) throws IOException {
         Configuration conf=new Configuration();
         FileSystem localInputFs=FileSystem.getLocal(conf);
         //FileSystem hdfsOutputFs=FileSystem.get(conf);
         String[] otherargs=new GenericOptionsParser(conf,args).getRemainingArgs();
         Path inputLocalDir=new Path(otherargs[0]);
         Path hdfsPathOutput=new Path(otherargs[1]);
         FileSystem hdfsOutputFs=hdfsPathOutput.getFileSystem(conf);
         try {
             FileStatus[] inputFiles=localInputFs.listStatus(inputLocalDir);
             FSDataOutputStream out=hdfsOutputFs.create(hdfsPathOutput,new Progressable() {

                 @Override
                 public void progress() {
                     System.out.print(".");

                 }
             });
             for(int i=0;i<inputFiles.length;i++)
             {
                 FSDataInputStream in=localInputFs.open(inputFiles[i].getPath());
                 byte[] buffer=new byte[100];
                 int byteRead=0;
                 while((byteRead=in.read(buffer))>0)
                 {
                     out.write(buffer, 0, byteRead);

                 }
                 in.close();
             }
             out.close();
             //localInputFs.delete(inputLocalDir);

         } catch (IOException e) {
             // TODO: handle exception
             e.printStackTrace();
         }
     }

 }

在参数中输入：/home/haduser/workspace/MergeCDFiles/resources/    hdfs://localhost:9000/opt/hadoop/tmp/test/a.txt

伪分布模式下用FileSystem.get(conf) 获取hdfs会出现：

Exception in thread "main" java.lang.IllegalArgumentException: Wrong FS: hdfs://localhost:9000/opt/hadoop/tmp/test, expected: file:///

at org.apache.hadoop.fs.FileSystem.checkPath(FileSystem.java:390)
    at org.apache.hadoop.fs.RawLocalFileSystem.pathToFile(RawLocalFileSystem.java:55)
    at org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:340)
    at org.apache.hadoop.fs.ChecksumFileSystem.mkdirs(ChecksumFileSystem.java:492)
    at org.apache.hadoop.fs.ChecksumFileSystem.create(ChecksumFileSystem.java:377)
    at org.apache.hadoop.fs.ChecksumFileSystem.create(ChecksumFileSystem.java:364)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:564)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:464)
    at com.bq.pro.MergeFiles.main(MergeFiles.java:26)

使用FileSystem hdfsOutputFs=hdfsPathOutput.getFileSystem(conf);来代替的时候就不会用问题，具体原因不详，应该是伪分布下的问题，在集群里应该不会有问题。