java 检测可用端口
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检测本机正在使用的服务端口，尽量快完成，计算消耗时间：
轮询：
1 public class test implements Runnable { 2 //private static String host="210.39.3.164"; 3 private static int i=0; 4 static Date one,two; 5 public synchronized int get(){ 6 if(i>=1024)notifyAll(); 7 return i++; 8 } 9 10 public static void main(String argv[]){ 11 one=new Date(); 12 //long time=one.getTime()-two.getTime(); 13 //System.out.println(time); 14 ExecutorService pool = Executors.newFixedThreadPool(30); 15 for(int j=0;j<15;j++){ 16 pool.submit(new Thread(new test())); 17 } 18 pool.shutdown(); 19 while(true){ 20 if(pool.isTerminated()){ 21 System.out.println(two.getTime()-one.getTime()); 22 break; 23 } 24 } 25 } 26 27 public void run(){ 28 int temp; 29 while((temp=get())<1024){ 30 try { 31 Socket s=new Socket(InetAddress.getLocalHost(),temp); 32 System.out.println("服务端口: "+temp); 33 s.close(); 34 } catch (UnknownHostException e) { 35 // TODO Auto-generated catch block 36 e.printStackTrace(); 37 } catch(ConnectException e){ 38 System.out.println(temp+"不是服务端口"); 39 }catch (IOException e) { 40 // TODO Auto-generated catch block 41 e.printStackTrace(); 42 } 43 if(temp==1023){ 44 two=new Date(); 45 } 46 } 47 } 48 }
尽量多开线程：
public class test {
public static void main(String argv[]){
int i;
Date d=new Date();
ExecutorService pool = Executors.newFixedThreadPool(1204);
for(i=1;i<=1024;i++){
pool.submit(new Thread(new thread(i)));
}
pool.shutdown();
while(true){
if(pool.isTerminated()){
Date last=new Date();
System.out.println(last.getTime()-d.getTime());
break;
}
}
}
}
class thread implements Runnable{
int i;
thread(int i){
this.i=i;
}
public void run(){
try {
Socket s=new Socket(InetAddress.getLocalHost(),i);
System.out.println("服务端口: "+i);
s.close();
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch(ConnectException e){
//System.out.println(i+"不是服务端口");
}catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
轮询方法使用了线程同步，但是没有多开线程方法速度快
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