MappedByteBuffer

MappedByteBuffer是java nio引入的文件内存映射方案，读写性能极高。在NIO中主要用到普通的输入流，带缓冲的输入流，RandomAccessFile和MappedByteBuffer。

@Test
public void mmapTest() throws Exception {

    FileChannel fileChannel = null;
    try {
        String filePath = "D:\\temp\\avatar.jpg";
        fileChannel = new RandomAccessFile(new File(filePath), "rw").getChannel();
        MappedByteBuffer mappedByteBuffer = fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, fileChannel.size());
        byte[] bytes = new byte[(int) fileChannel.size()];
        mappedByteBuffer.get(bytes);
        print(bytes);

    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (fileChannel != null) {
            try {
                fileChannel.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}


public static void print(byte[] bytes) {
    for (int i = 0; i < bytes.length; i++) {
        System.out.printf("0x%02X ", bytes[i]);
        if ((i + 1) % 8 == 0 || i + 1 == bytes.length) {
            System.out.print("\n");
        }
    }
}

标签：bytes,MappedByteBuffer,fileChannel,print,new,byte
来源： https://www.cnblogs.com/vipsoft/p/16458161.html