java获取字符串格式日期向前或向后n天的日期

private void setTilteMessage(){
BaseDao dao = new BaseDao();
String titleData = dao.getLatestData();
dao.closeDB();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
try {
Date date = sdf.parse(titleData);
Calendar   calendar   =   new   GregorianCalendar();
calendar.setTime(date);
calendar.add(calendar.DATE,1);//把日期往后增加一天.整数往后推,负数往前移动
date=calendar.getTime();   //这个时间就是日期往后推一天的结果
String putDate = sdf.format(date); //增加一天后的日期

} catch (ParseException e) {
e.printStackTrace();
}
}