Example of read/write from/to HDFS

1) Obtain file system

Configuration conf = new Configuration();

FileSystem fs = FileSystem.get(conf);

2) Get list of file by path and read all files line by line:

    FileStatus[] fileStatuses = fs.listStatus(new Path(path));
    for (FileStatus fileStatus : fileStatuses) {
    System.out.println("fileStatus: " + fileStatus.getPath().getName());
    if (!fileStatus.isFile())
        continue;

    BufferedReader bufferedReader = null;
    try {
        bufferedReader = new BufferedReader(new InputStreamReader(fs.open(fileStatuses[0].getPath())));

        String line;
        while ((line = bufferedReader.readLine()) != null) {

            ...
        }
    } finally {
        IOUtils.closeStream(bufferedReader);
    }
}

3) write to file

    BufferedWriter out = null;
    try {
        out = new BufferedWriter(new OutputStreamWriter(fs.create(new Path(path + "result.txt"))));

       
        out.write("text");

    } finally {
        IOUtils.closeStream(out);
    }