Hadoop dir/file last modification times

问题:

Is there a way to get the last modified times of all dirs and files in hdfs? I want to create page that displays the information, but I have no clue how to go about getting the last mod times all in one .txt file.

回答1:

See if it helps :

public class HdfsDemo {

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

        Configuration conf = new Configuration();
        conf.addResource(new Path("/Users/miqbal1/hadoop-eco/hadoop-1.1.2/conf/core-site.xml"));
        conf.addResource(new Path("/Users/miqbal1/hadoop-eco/hadoop-1.1.2/conf/hdfs-site.xml"));
        FileSystem fs = FileSystem.get(conf);
        System.out.println("Enter the directory name : ");
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        Path path = new Path(br.readLine());
        displayDirectoryContents(fs, path);
        fs.close();
    }

    private static void displayDirectoryContents(FileSystem fs, Path rootDir) {
        // TODO Auto-generated method stub
        try {

            FileStatus[] status = fs.listStatus(rootDir);
            for (FileStatus file : status) {
                if (file.isDir()) {
                    System.out.println("DIRECTORY : " + file.getPath() + " - Last modification time : " + file.getModificationTime());
                    displayDirectoryContents(fs, file.getPath());
                } else {
                    System.out.println("FILE : " + file.getPath() + " - Last modification time : " + file.getModificationTime());
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

One thing to notice though, getModificationTime() returns the modification time of file in milliseconds since January 1, 1970 UTC.

回答2:

You probably have to iterate through the files and directories, to get the status of each path - you can use the below code (just sample) - but I'm not sure, how efficient that would be, if you have large set of files and directories.

Configuration conf = new Configuration();
conf.set("fs.default.name", "hdfs://<namenod_ip_address:<port>");
conf.set("mapred.job.tracker", "<jobtracker_ip_address>:<port>");
conf.setBoolean("fs.hdfs.impl.disable.cache", true);

FileSystem lfs = FileSystem.get(l_configuration);
fs.getFileStatus(new Path("/your/path")).getModificationTime();