package aa;

import java.io.*;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.*;

public class WriteHdfs {

    public static void main(String[] args) {

        Configuration conf = new Configuration();

        try {

            FileSystem fs = FileSystem.get(conf);

            Path f = new Path("ttt.txt");

            System.out.println(fs.isFile(f));

            System.out.println(f.toString());

            FSDataOutputStream os = fs.create(f, true);

            os.writeChars("test");

            os.flush();

            os.close();

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

}

package aa;

import java.io.InputStream;

import java.net.URI;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.*;

import org.apache.hadoop.io.IOUtils;

public class ReadHdfs {

    public static void main(String[] args) throws Exception {

        String uri = "ttt.txt";

        Configuration conf = new Configuration();

    FileSystem fs = FileSystem. get(URI.create (uri), conf);

    InputStream in = null;

    try {

         in = fs.open( new Path(uri));

         IOUtils.copyBytes(in, System.out, 4096, false);

        } finally {

         IOUtils.closeStream(in);

        }

    }

}

log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).

log4j:WARN Please initialize the log4j system properly.

log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
t e s t