学步园

3.2.2 半关闭（不发送，仍接收）

Socket socket = new Socket(host,port);

Scanner in = new Scanner(Socket.getInputStream());

PrintWriter writer = new PrintWriter(socket.getOutputStream());

3.3 可中断套接字

java.nio包

SocketChannel类：NIO缓存。

SocketChannel channel = SocketChannel.open(new InetSocketAddress(host,port));

Scanner in = new Scanner(channel);

3.4 发送Email

3.5 建立URL连接