NIO(NO-Blocking I/O)模型
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.util.Iterator;
import java.util.Set;
public class SimpleNioServer {
public void startServer(int port) throws IOException {
Selector selector = Selector.open();
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.bind(new InetSocketAddress(port));
serverSocketChannel.configureBlocking(false);
serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
while (true) {
selector.select(); // Wait for an event
Set<SelectionKey> selectedKeys = selector.selectedKeys();
Iterator<SelectionKey> iter = selectedKeys.iterator();
while (iter.hasNext()) {
SelectionKey key = iter.next();
if (key.isAcceptable()) {
registerClient(serverSocketChannel, selector);
}
if (key.isReadable()) {
answerClient(key);
}
iter.remove();
}
}
}
private void registerClient(ServerSocketChannel serverSocketChannel, Selector selector) throws IOException {
SocketChannel clientChannel = serverSocketChannel.accept();
clientChannel.configureBlocking(false);
clientChannel.register(selector, SelectionKey.OP_READ);
System.out.println("New client connected: " + clientChannel);
}
private void answerClient(SelectionKey key) throws IOException {
SocketChannel clientChannel = (SocketChannel) key.channel();
ByteBuffer buffer = ByteBuffer.allocate(256);
int read = clientChannel.read(buffer);
if (read == -1) {
clientChannel.close();
System.out.println("Client disconnected: " + clientChannel);
return;
}
buffer.flip();
while (buffer.hasRemaining()) {
clientChannel.write(buffer);
}
buffer.clear();
}
public static void main(String[] args) {
SimpleNioServer server = new SimpleNioServer();
try {
server.startServer(8080);
} catch (IOException e) {
e.printStackTrace();
}
}
}