public static void main(String[] args) throws InterruptedException { Scanner cin = new Scanner(System.in); Peers p1 = new Peers(P1ID, P1UploadPort, P1DownloadPort, CheckPort[0]); p1.sum = new File("C:/users/ben/Desktop/Peers/P" + p1.PeerID + "/summary" + ".txt"); p1.downloadfromServer(); Uploading upload = new Uploading(p1); Thread t1 = new Thread(upload); Downloading t2 = new Downloading(p1); t1.start(); p1.waitforDownloading(); Thread.sleep(1000); // 否则会downloadPort开了,但是对应的uploadPort还没开启。 t2.start(); }