Data into the HDFS is written using the FileSystem and OutputStreamWriter Object available in hadoop.fs and java.io package that writes the data as string.FSDataOutputStream and FileSystem objects are used to append the data into the existing file.
import java.util.*;
import java.net.*;
import org.apache.hadoop.fs.*;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;
public class appendData {
public static void main(String[] args) throws Exception {
try {
Configuration conf = new Configuration();
Path path = new Path(“hdfs://localhost:54310/home/WriteData”);
FileSystem hdfs = path.getFileSystem(conf);
BufferedReader bfr = new BufferedReader(new InputStreamReader(hdfs.open(path))); //open file first
String str = null;
BufferedWriter br = new BufferedWriter(new OutputStreamWriter(hdfs.create(path, true)));
while ((str = bfr.readLine()) != null) {
br.write(str); // write file content
br.newLine();
}
br.write(“Append Data to HDFS”); // append into file
br.newLine();
br.close(); // close it
} catch (Exception e) {
System.out.println(“File not found”);
}
}
}
