详解如何把cmd黑窗口把java文件打包成jar

import java.io.File;
import java.util.Calendar;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
public class quarty1 extends TimerTask {
    private static final String targetPath1 = "C:\\Users\\Administrator\\Downloads\\";
    //private static final String targetPath2 = "D:\\kankan\\VaCache";
    private Timer timer = new Timer();

    private Calendar calendar = Calendar.getInstance();
    public static void main(String[] args) {
        quarty1 fm = new quarty1();
        fm.start();
    }
    private static void delFiles(String[] dir) {
        for (int i = 0; i < dir.length; i++) {
            File f = new File(dir[i]);
            File[] files = null;
            if (f.exists()) {
                files = f.listFiles();
                for (int j = 0; j < files.length; j++) {
                    files[j].delete();
                }
            }
        }
    }
    public void start() {
        //每晚九点自动清楚下载目录文件
        timer.scheduleAtFixedRate(this, new Date(), 1000 * 1440 * 60);//10分钟转化为毫秒
        System.out.println("-------------------》》》每晚九点自动清楚下载目录文件》》》----------------- ");
    }

    public void run() {
        //在每天的23:30后不再执行
        //delFiles(new String[] { targetPath1, targetPath2 });
        delFiles(new String[] { targetPath1});
        if(calendar.get(Calendar.HOUR_OF_DAY) ==23 && calendar.get(Calendar.MINUTE) == 30){
            this.cancel();
        }
    }
}