取得上一天的时间，取得下一天的时间

  public static String getDate(){
    Calendar cd=Calendar.getInstance();
    SimpleDateFormat sd=new SimpleDateFormat("yyyy-MM-dd");
    return sd.format(cd.getTime());
   }
public static void main(String ss[]){
String aaaa = getDate();
Date now = java.sql.Date.valueOf(aaaa);

System.out.println("now========" + now.toString());

Calendar cd = Calendar.getInstance();
cd.setTime(now);

cd.add(cd.DATE, 1);

Date nextday = cd.getTime();

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

System.out.println("next========" + sdf.format(nextday));

Calendar   c   =   Calendar.getInstance();
c.add(Calendar.DAY_OF_MONTH, -1);
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String mDateTime=formatter.format(c.getTime());
String strStart=mDateTime.substring(0, 16);//2007-10-29 09:30
System.out.println("update========"+strStart);

}