[Java] Socket

public class SocketServerTest implements java.lang.Runnable{
    private int PORT = 52288;
    private java.net.ServerSocket server = null;
    private boolean shutdown = false;
    public void run(){
        try{
            server = new java.net.ServerSocket(PORT);
            try{
                while(!shutdown){
                    java.net.Socket socket = server.accept();
                    try{
                        //非 140.113 就關掉
                        if( (( ((socket.getInetAddress()).getHostAddress()).substring(0,8)).compareTo("140.113.") != 0 ) ){
                            socket.close();
                            continue;
                        }

                        String datain = null;
                        java.io.BufferedReader in = new java.io.BufferedReader( new java.io.InputStreamReader( socket.getInputStream(),"UTF-8" ) );
                        datain = in.readLine();
                    }catch(java.net.SocketException e){
                        //socket關掉
                    }catch(java.lang.NullPointerException e){
                        //in.readLine()
                    }finally{
                        socket.close();
                    }
                }
            }catch(java.net.SocketException e){
                    //socket關掉
            }finally{
                server.close();
            }
        }catch(java.net.SocketException e){
                //socket關掉
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}