使用NIO写入文件时缺少新行

Question

i am trying to copy the content of one file to new file and somehow new line are missing in the new file and its created as one row, i guess its related to buffer position. following the code that i am using..

List<String> lines;
        FileChannel destination = null;
        try
        {
            lines = Files.readAllLines(Paths.get(sourceFile.getAbsolutePath()), Charset.defaultCharset());
            destination = new FileOutputStream(destFile).getChannel();
            ByteBuffer buf = ByteBuffer.allocate(1024);
            for (String line : lines)
            {
                System.out.println(line);
                buf.clear();
                buf.put(line.getBytes());
                buf.flip();
                while (buf.hasRemaining())
                {
                    destination.write(buf);
                }
            }
        }
        finally
        {
            if (destination != null)
            {
                destination.close();
            }

        }

Answer 1

Do buff.put(System.getProperty("line.separator").toString()); before buf.put(line.getBytes());

Answer 2

The line where you're writing the bytes:

buf.put(line.getBytes());

...doesn't include the new line character, you're just writing the bytes of each individual line. You need to write the new line character separately after each instance.

Answer 3

You might prefer to use Java 7's Files.copy:

Files.copy(sourceFile.toPath(), destinationFile.toPath(),
        StandardCopyOption.REPLACE_EXISTING);

One should once write a file copy oneself. However your current version uses the default platform encoding to read the file as text . This goes wrong on UTF-8 (some illegal multibyte sequences), on the \ nul char, converts the line endings to the default platform ones.

Answer 4

This will include the new line:

   ByteBuffer bf = null;
   final String newLine = System.getProperty("line.separator");
   bf = ByteBuffer.wrap((yourString+newLine).getBytes(Charset.forName("UTF-8" )));

Answer 5

您可以直接使用由System.getProperty("line.separator")插入的System.lineSeparator() System.getProperty("line.separator")

buff.put(System.lineSeparator().toString());