JAVA-NIO实战

一、NIO在文件读写方面相对于传统IO来说，性能高很多
/**
* 文件读写的NIO
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException {

//1.NIO采用通道+缓存区使得新式的IO操作直接面向缓存区，并且是非阻塞的

//2.Channel是支持读写双向操作，基于RandomAccessFile实现的

RandomAccessFile file =new RandomAccessFile("C:\\Users\\hejie\\Downloads\\hao123.txt", "r");

FileChannel channel = file.getChannel();

ByteBuffer buffer = ByteBuffer.allocate((int)file.length());

//3.利用RandomAccessFile的读指针

channel.read(buffer);

//4.切换缓存区为读模式

buffer.flip();

byte[] res = new byte[(int)file.length()];

buffer.get(res,0, buffer.limit());

System.out.println(new String(res));

RandomAccessFile file2 =new RandomAccessFile("C:\\Users\\hejie\\Downloads\\new-hao12