Java实现简单的HTTP服务器代码详解编程语言

import java.net.*; 
import java.nio.ByteBuffer; 
import java.nio.channels.*; 
import java.nio.charset.*; 
import java.util.concurrent.*; 
import java.io.*; 
 
public class SimpleHttpServer { 
	private int port = 80; 
	private ServerSocketChannel serverSocketChannel = null; 
	private ExecutorService executorService; 
	private static final int POOL_MULTIPLE = 4; 
 
	public SimpleHttpServer() throws IOException { 
		executorService = Executors.newFixedThreadPool(Runtime.getRuntime() 
				.availableProcessors() * POOL_MULTIPLE); 
		serverSocketChannel = ServerSocketChannel.open(); 
		serverSocketChannel.socket().setReuseAddress(true); 
		serverSocketChannel.socket().bind(new InetSocketAddress(port)); 
	} 
 
	public void service() { 
		while (true) { 
			SocketChannel socketChannel = null; 
			try { 
				socketChannel = serverSocketChannel.accept(); 
				executorService.execute(new Handler(socketChannel)); 
			} catch (IOException e) { 
				e.printStackTrace(); 
			} 
		} 
	} 
 
	public static void main(String[] args) throws IOException { 
		new SimpleHttpServer().service(); 
	} 
 
} 
 
class Handler implements Runnable { 
	private SocketChannel socketChannel; 
	public Handler(SocketChannel socketChannel) { 
		this.socketChannel = socketChannel; 
	} 
 
	@Override 
	public void run() { 
		handle(socketChannel); 
	} 
 
	private void handle(SocketChannel socketChannel) { 
		try { 
			Socket socket = socketChannel.socket(); 
			System.out 
					.println(socket.getInetAddress() + ":" + socket.getPort()); 
			ByteBuffer buffer = ByteBuffer.allocate(1024); 
			socketChannel.read(buffer); 
			buffer.flip(); 
			String request = decode(buffer); 
			StringBuffer sb = new StringBuffer("HTTP/1.1 200 OK/r/n"); 
			sb.append("Content-Type:text/html/r/n/r/n"); 
			socketChannel.write(encode(sb.toString())); 
			FileInputStream in = null; 
			String firstLineOfRequest = request.substring(0, 
					request.indexOf("/r/n")); 
			if (firstLineOfRequest.indexOf("login.htm") != -1) 
				in = new FileInputStream("login.htm"); 
			else 
				in = new FileInputStream("hello.htm"); 
			FileChannel fileChannel = in.getChannel(); 
			fileChannel.transferTo(0, fileChannel.size(), socketChannel); 
		} catch (IOException e) { 
			e.printStackTrace(); 
		} finally { 
			try { 
				if (socketChannel != null) 
					socketChannel.close(); 
			} catch (IOException e) { 
				e.printStackTrace(); 
			} 
		} 
	} 
 
	private Charset charset = Charset.forName("GBK"); 
 
	private ByteBuffer encode(String string) { 
		return ByteBuffer.allocate(string.length() * 2).get( 
				string.getBytes(charset)); 
	} 
 
	private String decode(ByteBuffer buffer) { 
		byte[] source = new byte[buffer.position() + 1]; 
		buffer.put(source); 
		return new String(source, charset); 
	} 
}