java.nio的に読み書き

今更感ありあふれますがさっくり。
ついStream直で書いちゃう癖なおしたいですね。

不定の型に対する場合

Channels.java

ReadableByteChannel inChannel = Channels.newChannel(InputStream);
WritableByteChannel outChannel = Channels.newChannel(OutputStream);

ByteBuffer buffer = ByteBuffer.allocate(102400);

for (int readBytes = inChannel.read(buffer); readBytes != -1; readBytes = inChannel.read(buffer)) {
    buffer.flip();
    outChannel.write(buffer);
    buffer.clear();
}

ファイルの読み書き1

FileChannel1.java

File srcFile = new File(IN);
FileChannel in = new FileInputStream(srcFile).getChannel();
FileChannel out = new FileOutputStream(new File(OUT)).getChannel();

out.write(in.map(FileChannel.MapMode.READ_ONLY, 0, srcFile.length));

ファイルの読み書き2

FileChannel2.java

FileChannel in = new FileInputStream(new File(IN)).getChannel();
FileChannel out = new FileOutputStream(new File(OUT)).getChannel();

in.transferTo(0, in.size(), out);