Read a file in HDFS

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.FSDataOutputStream;

首先 先建立一個FileSystem物件，在建立此物件時，必需傳入一個Configuration object，因此

我們先Create一個Configuration object

Configuration conf = new Configuration();

FileSystem fs = FileSystem.get(conf);

之後就可以用這個 FileSystem object來開檔，創出一個FSDataInputStream object

Path inFile = new Path("/tmp/test");

FSDataInputStream in = fs.open(outFile);

之後就用

in.read(long position, byte[] buffer, int offset, int length)

in.readFully(long position, byte[] buffer)

來讀檔