Writing to HDFS from Java, getting “could only be replicated to 0 nodes instead of minReplication”

Question

I’ve downloaded and started up Cloudera\'s Hadoop Demo VM for CDH4 (running Hadoop 2.0.0). I’m trying to write a Java program that will run from my windows 7 machine (The same

Answer 1

Here is how I create files in the HDFS:

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

FileSystem hdfs = FileSystem.get(context.getConfiguration());
Path outFile=new Path("/path to store the output file");

String line1=null;

if (!hdfs.exists(outFile)){
            OutputStream out = hdfs.create(outFile);
            BufferedWriter br = new BufferedWriter(new OutputStreamWriter(out, "UTF-8"));
            br.write("whatever data"+"\n");
            br.close();
            hdfs.close();
        }
else{
            String line2=null;
            BufferedReader br1 = new BufferedReader(new InputStreamReader(hdfs.open(outFile)));
            while((line2=br1.readLine())!=null){
                line1=line1.concat(line2)+"\n";
            }
            br1.close();
            hdfs.delete(outFile, true);
            OutputStream out = hdfs.create(outFile);
            BufferedWriter br2 = new BufferedWriter(new OutputStreamWriter(out, "UTF-8"));
            br2.write(line1+"new data"+"\n");
            br2.close();
            hdfs.close();
        }