Java讀寫HDFS簡單Demo

環境：Eclipse + Eclipse Hadoop插件， Hadoop + RHEL6.4

Java讀寫HDFS簡單Demo

package test;

import java.io.IOException;
import java.net.URI;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;;

public class Test {
 
 
 public void WriteFile(String hdfs) throws IOException {
  Configuration conf = new Configuration();
  FileSystem fs = FileSystem.get(URI.create(hdfs),conf);
  FSDataOutputStream hdfsOutStream = fs.create(new Path(hdfs));
  hdfsOutStream.writeChars("hello");
  hdfsOutStream.close();
  fs.close(); 
 }
 
 public void ReadFile(String hdfs) throws IOException {
  Configuration conf = new Configuration();
  FileSystem fs = FileSystem.get(URI.create(hdfs),conf);
  FSDataInputStream hdfsInStream = fs.open(new Path(hdfs));
 
  byte[] ioBuffer = new byte[1024];
  int readLen = hdfsInStream.read(ioBuffer);
  while(readLen!=-1)
  {
   System.out.write(ioBuffer, 0, readLen);
   readLen = hdfsInStream.read(ioBuffer);
  }
  hdfsInStream.close();
  fs.close(); 
 }
 
 public static void main(String[] args) throws IOException { 
  String hdfs = "hdfs://192.168.56.112:9000/test/hello.txt";
  Test t = new Test(); 
  t.WriteFile(hdfs);
  t.ReadFile(hdfs);
  }
}

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將本地文件拷到HDFS中 http://www.linuxidc.com/Linux/2013-05/83866.htm

從HDFS下載文件到本地 http://www.linuxidc.com/Linux/2012-11/74214.htm

將本地文件上傳至HDFS http://www.linuxidc.com/Linux/2012-11/74213.htm

HDFS基本文件常用命令 http://www.linuxidc.com/Linux/2013-09/89658.htm

Hadoop中HDFS和MapReduce節點基本簡介 http://www.linuxidc.com/Linux/2013-09/89653.htm

《Hadoop實戰》中文版+英文文字版+源碼【PDF】 http://www.linuxidc.com/Linux/2012-10/71901.htm

Hadoop: The Definitive Guide【PDF版】 http://www.linuxidc.com/Linux/2012-01/51182.htm

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