java获取当前时间，将天数减一天，返回Date
要什么格式的？给你个这样的“yy-mm-dd hh-mm-ss”//根据时间字符串把天数加1 public String addOneDay(String time) { String add = null; try { SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); java.util.Date timeNow = df.parse(time); Calendar begin=Calendar.getInstance(); begin.setTime(timeNow); begin.add(Calendar.DAY_OF_MONTH,1); add = df.format(begin.getTime()); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } return add; }这是加1的你把1改成-1就行了获取当前时间的函数：//获取当前时间 public String getTime() { TimeZone tz = TimeZone.getTimeZone("Asia/Shanghai"); TimeZone.setDefault(tz); Calendar rightNow = Calendar.getInstance(); SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //格式大小写有区别 String sysDatetime = fmt.format(rightNow.getTime()); return sysDatetime; }