Computes the last day of the month

When the time passed by the front end is up to the month, calculate the last date of the incoming end month

 public static String getLastDayOfMonth(String yearMonth) {

        int year = Integer.parseInt(yearMonth.split("-")[0]);  //年
        int month = Integer.parseInt(yearMonth.split("-")[1]); //月
        Calendar cal = Calendar.getInstance();
        // 设置年份
        cal.set(Calendar.YEAR, year);
        // 设置月份
        // cal.set(Calendar.MONTH, month - 1);
        cal.set(Calendar.MONTH, month); //设置当前月的上一个月
        // 获取某月最大天数
        //int lastDay = cal.getActualMaximum(Calendar.DATE);
        int lastDay = cal.getMinimum(Calendar.DATE); //获取月份中的最小值，即第一天
        // 设置日历中月份的最大天数
        //cal.set(Calendar.DAY_OF_MONTH, lastDay);
        cal.set(Calendar.DAY_OF_MONTH, lastDay - 1); //上月的第一天减去1就是当月的最后一天
        // 格式化日期
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        return sdf.format(cal.getTime());
    }