获取过去12个月

/**
     * 获取过去12个月
     */
    public static void main(String[] args) {
        String[] last12Months = new String[12];
        Calendar calendar = Calendar.getInstance();
        //如果当前日期大于二月份的天数28天或者29天会导致计算月份错误，会多出一个三月份，故设置一个靠前日期解决此问题
        calendar.set(Calendar.DAY_OF_MONTH, 1);
        System.out.println(Calendar.MONTH);
        calendar = setTime();
        for (int i = 0; i < 12; i++) {
//            System.out.println("-----" + (calendar.get(Calendar.MONTH)));
            if (calendar.get(Calendar.MONTH) != 0) {
                last12Months[11 - i] = calendar.get(Calendar.YEAR) + "-" + (calendar.get(Calendar.MONTH));
            } else {
                last12Months[11 - i] = calendar.get(Calendar.YEAR) - 1 + "-" + 12;
            }
//            last12Months[11 - i] = cal.get(Calendar.YEAR) + "-" + (cal.get(Calendar.MONTH));

//            last12Months[11 - i] = (new SimpleDateFormat("yyyy-MM")).format(setTime().getTime());
            //逐次往前推1个月
            calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH) - 1);
        }
        for (int i = 0; i < last12Months.length; i++) {
            System.out.println(last12Months[i]);
        }

    }

    public static Calendar setTime() {
        // 创建 Calendar 对象
        Calendar calendar = Calendar.getInstance();  // 默认是当前日期

        try {
            // 对 calendar 设置时间的方法
            // 设置传入的时间格式
            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM");
            // 指定一个日期
            Date date = dateFormat.parse("2019-01");
            // 对 calendar 设置为 date 所定的日期
            calendar.setTime(date);

            System.out.println(calendar.get(Calendar.YEAR));
            System.out.println(calendar.get(Calendar.MONTH));
            // 按特定格式显示刚设置的时间
            String str = (new SimpleDateFormat("yyyy-MM")).format(calendar.getTime());
            System.out.println("=======" + str);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return calendar;
    }