1.可以传输一个Object ，不过肯定要序列化，所以实现java.io.Serializable接口就是必不可少的。
is = new ObjectInputStream(new BufferedInputStream(socket.getInputStream())); os = new ObjectOutputStream(socket.getOutputStream()); Object obj = is.readObject(); User user = (User)obj; os.writeObject(user); os.flush();
2.传输压缩对象节省流量。
gzipis = new GZIPInputStream(socket.getInputStream()); ois = new ObjectInputStream(gzipis); gzipos = new GZIPOutputStream(socket.getOutputStream()); oos = new ObjectOutputStream(gzipos);
3.剩下的就是加密了(SSL)
` ServerSocketFactory factory = SSLServerSocketFactory.getDefault();
ServerSocket server = factory.createServerSocket(5000);
SocketFactory factory = SSLSocketFactory.getDefault();
socket = factory.createSocket("localhost", 5000); `
产生keystore文件了，运行下面的命令:
keytool -genkey -alias mysocket -keyalg RSA -keystore e:\testsocket.jks
运行Server:
java -Djavax.net.ssl.keyStore=testsocket.jks -Djavax.net.ssl.keyStorePassword=testsocket com.liuyi.socket.test.socket.ssl.MyServer
运行Client:
java -Djavax.net.ssl.trustStore=testsocket.jks -Djavax.net.ssl.trustStorePassword=testsocket com.liuyi.socket.test.socket.ssl.MyClient
对于SSL生成部分可以参考：
http://www.cnblogs.com/draem0507/archive/2013/05/08/3067252.html
