使用技巧：通过Java.net包建立双向通讯

try{ 

boolean flag=true; 
Socket clientSocket=null; 

ServerSocket serverSocket = new ServerSocket(0); 
System.out.println("Server listen on: " +serverSocket.getLocalPort()); 

while(flag){ 
clientSocket=serverSocket.accept(); 
DataInputStream is=new DataInputStream( new bufferedInputStream(client 
Socket.getInputStream())); 
PrintStream os=new PrintStream( new bufferedOutputStream(clientSocket. 
getOutputStream())); 
// 处理Applet请求 
os.close(); 
is.close(); 
clientSocket.close(); 
} 
serverSocket.close(); 
}catch( IOException e){ 
System.err.println(" Exception: "+e); 
}

try { 
Socket clientSocket =new Socket("serverName",7); 
OutputStream os=clientSocket.getOutputStream(); 
DataInputStream is=new DataInputStream( clientSocket.getInputStream()) 
; 
// 其它操作. 
os.close(); 
is.close(); 
clientSocket.close(); 
}catch(Exception e){ 
System.err.println("Exception:"+e); 
}