Java 简单的时间操作——简单的加减运算 ._java 测试键盘输入的是否是加减乘除运算符-优快云博客

本文介绍了一种在Java中进行日期加法运算的方法，并演示了如何获取指定周期（如上月、本月、上周、本周）的开始与结束日期。通过具体代码示例展示了不同时间段的计算逻辑。

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public static String timeAdd(String date, int minute) {
 
 
    Calendar calendar = Calendar.getInstance();
 
    DateFormat df = new SimpleDateFormat("yyyyMMddHHmmss");
    try {
        Date d = df.parse(date);
        calendar.setTime(d);
    } catch (Exception ex) {
    }
    calendar.setTimeInMillis(calendar.getTimeInMillis() + minute * 60
            * 1000);
    String time = df.format(calendar.getTime());
  
    return time;
}

System.out.println("******lastmonth****thismonth***lastweek****thisweek***");
  String[] datePeriods = { "lastMonth", "thisMonth", "lastWeek",
    "thisWeek" };
  for (String datePeriod : datePeriods) {
   Calendar startDate = Calendar.getInstance();
   Calendar endDate = Calendar.getInstance();

   if ("lastMonth".equals(datePeriod)) {
    endDate.add(Calendar.DAY_OF_MONTH,
      -endDate.get(Calendar.DAY_OF_MONTH));
    startDate.add(
      Calendar.DAY_OF_MONTH,
      -startDate.get(Calendar.DAY_OF_MONTH) + 1
        - endDate.get(Calendar.DAY_OF_MONTH));
   } else if ("thisMonth".equals(datePeriod)) {
    startDate.add(Calendar.DAY_OF_MONTH,
      1 - endDate.get(Calendar.DAY_OF_MONTH));
   } else if ("lastWeek".equals(datePeriod)) {
    endDate.add(Calendar.DAY_OF_MONTH,
      - endDate.get(Calendar.DAY_OF_WEEK));
    startDate.add(Calendar.DAY_OF_MONTH,
      -6 - startDate.get(Calendar.DAY_OF_WEEK));
   } else {
    startDate.add(Calendar.DAY_OF_MONTH,
      1 - startDate.get(Calendar.DAY_OF_WEEK));
   }

   System.out.println("First Day Of "+datePeriod+" is:"+format.format(startDate.getTime()));
   System.out.println("End Day Of "+datePeriod+" is:"+format.format(endDate.getTime()));
  }