删除用户

import java.nio.ByteBuffer;

import java.nio.charset.Charset;//来自 时   代     Java  公  众  号 - nowjava.com

import java.nio.file.*;

import java.nio.file.attribute.*;

import java.io.IOException;


/**

 * Example code to list/set/get/delete the user-defined attributes of a file.

 */


public class Xdd {


    static void usage() {

        System.out.println("Usage: java Xdd <file>");

        System.out.println("       java Xdd -set <name>=<value> <file>");

        System.out.println("       java Xdd -get <name> <file>");

        System.out.println("       java Xdd -del <name> <file>");

        System.exit(-1);

    }


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

        // one or three parameters

        if (args.length != 1 && args.length != 3)

            usage();/* from NowJava.com*/


        Path file = (args.length == 1) ? Paths.get(args[0]) : Paths

                .get(args[2]);


        // check that user defined attributes are supported by the file store

        FileStore store = Files.getFileStore(file);

        if (!store

                .supportsFileAttributeView(UserDefinedFileAttributeView.class)) {

            System.err.format(

                    "UserDefinedFileAttributeView not supported on %s\n",

                    store);

            System.exit(-1);


        }

        UserDefinedFileAttributeView view = Files.getFileAttributeView(

                file, UserDefinedFileAttributeView.class);


        // list user defined attributes

        if (args.length == 1) {

            System.out.println("    Size  Name");

            System.out

                    .println("--------  --------------------------------------");

            for (String name : view.list()) {

                System.out.format("%8d  %s\n", view.size(name), name);

            }

            return;

        }


        // Add/replace a file's user defined attribute

        if (args[0].equals("-set")) {

            // name=value

            String[] s = args[1].split("=");

            if (s.length != 2)

                usage();

            String name = s[0];

            String value = s[1];

            view.write(name, Charset.defaultCharset().encode(value));

            return;

        }


        // Print out the value of a file's user defined attribute

        if (args[0].equals("-get")) {

            String name = args[1];

            int size = view.size(name);

            ByteBuffer buf = ByteBuffer.allocateDirect(size);

            view.read(name, buf);

            buf.flip();

            System.out.println(Charset.defaultCharset().decode(buf)

                    .toString());

            return;

        }


        // Delete a file's user defined attribute

        if (args[0].equals("-del")) {

            view.delete(args[1]);

            return;

        }


        // option not recognized

        usage();

    }

}