int a=2
while(a > 1){
   run...
   Thread.sleep(24*3600*1000);// 每天跑一次
}

package com.javaer.thread;
 
public class TSleep implements Runnable  {
 
	public static void main(String[] args) {
		   Thread s1 = new Thread(new TSleep(),"S1");
		   Thread s2 = new Thread(new TSleep(),"S2");
           s1.start();
           s2.start();
	}
 
	@Override
	public void run() {
		// TODO Auto-generated method stub
		  for (int i = 0; i < 10; i++) {
              System.out.println("线程"+Thread.currentThread().getName()+"第" + i + "次执行！");
              try {
                      Thread.sleep(30);
              } catch (InterruptedException e) {
                      e.printStackTrace();
              }
      }
	}
 
}