SeekableByteChannel and File Attributes - Java File Path IO

Java examples for File Path IO:File Channel

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Introduction

Create a file with a specific set of file permissions for Unix and other POSIX file systems.

Demo Code

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SeekableByteChannel;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.nio.file.attribute.FileAttribute;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.PosixFilePermissions;
import java.util.EnumSet;
import java.util.Set;

public class Main {
  public static void main(String[] args) {
    Path path = Paths.get("home/folder1/email", "email.txt");
    ByteBuffer buffer = ByteBuffer.wrap("this is a test ".getBytes());

    // create the custom permissions attribute for the email.txt file
    Set<PosixFilePermission> perms = PosixFilePermissions
        .fromString("rw-r------");
    FileAttribute<Set<PosixFilePermission>> attr = PosixFilePermissions
        .asFileAttribute(perms);//from w w  w. j a v a 2  s  .c  om

    // write a file using SeekableByteChannel
    try (SeekableByteChannel seekableByteChannel = Files.newByteChannel(path,
        EnumSet.of(StandardOpenOption.CREATE, StandardOpenOption.APPEND), attr)) {

      int write = seekableByteChannel.write(buffer);
      System.out.println("Number of written bytes: " + write);

    } catch (IOException ex) {
      System.err.println(ex);
    }
    buffer.clear();
  }
}

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