nio http server 
短连接 

key.isAcceptable()
key.isReadable()
key.isWritable()

key.cancel();
// 写完就关闭  
socketChannel.close();


浏览器访问测试

doWrite done,time=0,java.nio.channels.SocketChannel[connected local=/127.0.0.1:8000 remote=/127.0.0.1:59105]
doWrite done,time=1,java.nio.channels.SocketChannel[connected local=/127.0.0.1:8000 remote=/127.0.0.1:59106]

remote=/127.0.0.1:59105
remote=/127.0.0.1:59106
浏览器打开的端口一直在变


完整代码
https://gitee.com/dyyx/hellocode/blob/master/src/nio/SimpleNioHttpServer.java


import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.time.LocalDateTime;
import java.util.Iterator;
import java.util.Set;

public class SimpleNioHttpServer {
	private static final int PORT = 8000;
	public static void main(String[] args) throws IOException {		 
		int port = getPort();
        Selector selector = Selector.open();
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        serverSocketChannel.socket().bind(new InetSocketAddress(port), 1024);
        serverSocketChannel.configureBlocking(false);
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
        
        System.out.println("SimpleNioHttpServer start,port="+port+","+serverSocketChannel);
       
        while (true) {
            selector.selectNow();
            Set<SelectionKey> selectionKeys = selector.selectedKeys();
            Iterator<SelectionKey> it = selectionKeys.iterator();
            while (it.hasNext()) {
                SelectionKey selectionKey = it.next();
                it.remove();
                handleInput(selector, selectionKey);
            }
        }
    }
 
    private static void handleInput(Selector selector, SelectionKey key) throws IOException {
        // 新连接 
        if (key.isAcceptable()) {
            SocketChannel socketChannel = ((ServerSocketChannel) key.channel()).accept();
            socketChannel.configureBlocking(false);
            socketChannel.register(selector, SelectionKey.OP_READ);
            System.out.println("Accept done,socketChannel="+socketChannel);
        }
        if (key.isReadable()) {
            SocketChannel socketChannel = (SocketChannel) key.channel();
            ByteBuffer buffer = ByteBuffer.allocate(4);
            String requestData = "";
            while (socketChannel.read(buffer) > 0) {
                buffer.flip();
                CharBuffer cb = Charset.forName("UTF-8").decode(buffer);
                requestData+=cb.toString();
                buffer.clear();
            }
            System.out.println("requestData="+requestData+"\n"+socketChannel);
            socketChannel.register(selector, SelectionKey.OP_WRITE);
        }
        
        if (key.isWritable()) {
            SocketChannel socketChannel = (SocketChannel) key.channel();
            StringBuffer stringBuffer = new StringBuffer();
            stringBuffer.append("HTTP/1.1 200 OK\n");
            stringBuffer.append("Content-Type: text/html; charset=UTF-8\n");
            stringBuffer.append("\n");
            stringBuffer.append("hello , SimpleNioHttpServer ,"+LocalDateTime.now());
            doWrite(socketChannel, stringBuffer.toString());           
            key.cancel();
            // 写完就关闭 ，短连接 
            socketChannel.close();
        }
    }
 
    private static void doWrite(SocketChannel channel, String response)
            throws IOException {
        System.out.println("doWrite start,"+channel);
        long start = System.currentTimeMillis();
        if (response != null && response.trim().length() > 0) {
            byte[] bytes = response.getBytes();
            ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length);
            writeBuffer.put(bytes);
            writeBuffer.flip();
            channel.write(writeBuffer);
        }
        long end = System.currentTimeMillis();
        long time = end - start;
        System.out.println("doWrite done,time="+time+","+channel);
    }
    
    private static final int getPort() {
		int port = PORT;
		try {
			port = Integer.parseInt(System.getProperty("port"));
		}catch(Throwable e) {
			// 
		}
		if(port<=0) {
			port = PORT;
		}
		return port;
	}	
}




BIO SimpleHttpServer
长连接 ，仅支持 GET
https://gitee.com/dyyx/hellocode/blob/master/src/SimpleHttpServer2.java