@Test
 public void dateTest() {
 Date today = new Date();
 for(int i=0;i<10;i++) {
 today = yesterday(today);
 System.out.println(today);
 }
 System.out.println("------------");
 for(int i=0;i<10;i++) {
 today = tomorrow(today);
 System.out.println(today);
 }

 }

 /**
 * 返回昨天
 * @param today
 * @return
 */
 public Date yesterday(Date today) {
 Calendar calendar = Calendar.getInstance();
 calendar.setTime(today);
 calendar.set(Calendar.DATE, calendar.get(Calendar.DATE) - 1);
 return calendar.getTime();
 }

 /**
 * 返回明天
 * @param today
 * @return
 */
 public Date tomorrow(Date today) {
 Calendar calendar = Calendar.getInstance();
 calendar.setTime(today);
 calendar.set(Calendar.DATE, calendar.get(Calendar.DATE) + 1);
 return calendar.getTime();
 }