public static void main(String[] args) throws Exception {
		FileInputStream finput = new FileInputStream("E://test.txt");
		FileChannel fchannel = finput.getChannel();
		ByteBuffer byteBf = ByteBuffer.allocate(1024);
		fchannel.read(byteBf);
		Charset charSet = Charset.forName("utf-8");
		byteBf.flip();
		System.out.println(charSet.decode(byteBf));

	}

/**
 * selector 只是一个通知，具体各个部分自行处理
 * 
 * NIO , 不阻塞，当有东西来了就开始通知处理，不然能一直select到·
 * 
 * @author hejb
 *
 */
public class Test {
	public static void main(String[] args) throws Exception {
		ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
		// 阻塞为false
		serverSocketChannel.configureBlocking(false);
		// 绑定IP和端口
		serverSocketChannel.socket().bind(new InetSocketAddress("0.0.0.0", 8080));
		Selector selector = Selector.open();
		// 注册感兴趣事件到selector
		serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
		while (selector.select() != 0) {

			Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
			while (iterator.hasNext()) {

				// 循选中事件
				SelectionKey selecttionKey = iterator.next();
				// 删除已经处理
				iterator.remove();
				if (selecttionKey.isAcceptable()) {
					// 返回注册该事件时的channel ，即SelectableChannel
					ServerSocketChannel channel = (ServerSocketChannel) selecttionKey.channel();
					// 有连接事件来了， 可以处理接收请求了,注意如果不进行accept，select.select()一直能轮询到东西
					// 接收后返回了个socketchannel，开始配置
					SocketChannel socketChannel = channel.accept();
					// 也配置成非阻塞处理
					socketChannel.configureBlocking(false);
					// 复用同一个selector上注册感兴趣的事件,并注册感兴趣的可读事件
					socketChannel.register(selector, selecttionKey.OP_READ);
				}
				// 如果来可以可读事件
				if (selecttionKey.isReadable()) {
					// 返回注册该事件时的channel ，即实现了SelectableChannel的
					SocketChannel socketChannel = (SocketChannel) selecttionKey.channel();
					// 后面就都是通过byteBuffer和channel来读操作了
					ByteBuffer byteBf = ByteBuffer.allocate(1024);
					socketChannel.read(byteBf);
					Charset charset = Charset.forName("utf-8");
					byteBf.flip();
					System.out.println("clinet :" + charset.decode(byteBf));
					// socket是双通道，故也可以直接返回东西了
					socketChannel.write(charset.encode("test only"));
				}
			}
		}
	}
	// 有个疑问，NIO的链接什么时候关闭呢，有文章说是在finalize方法里,待我去找找
}

public static String readFileWithoutBuffer() throws IOException {
        // BIO inputstream without buffer
        FileInputStream input = new FileInputStream("E://test.txt");
        byte[] content = new byte[1024];
        int length = input.read(content);
        input.close();
        return new String(content, 0, length);
    }

public static String readFileWithBuffer() throws IOException {
        // BIO inputstream with buffer
        FileInputStream input = new FileInputStream("E://test.txt");
        BufferedInputStream binpt = new BufferedInputStream(input);
        byte[] bufferContent = new byte[1024];
        int length = binpt.read(bufferContent);
        return new String(bufferContent, 0, length);
    }

 public synchronized int read() throws IOException {
        if (pos >= count) {
            fill(); // 如果读取大于缓存了，填充缓冲buff
            if (pos >= count)
                return -1;
        }
        return getBufIfOpen()[pos++] & 0xff;
    }