java計算本月之前的12個月

public static void main(String[] args) {
		String[] months = new String[12];
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.MONTH, cal.get(Calendar.MONTH));
		for(int i=0;i<12;i++){
			months[11-i] = cal.get(Calendar.YEAR)+"-"+(cal.get(Calendar.MONTH)+1);
			cal.set(Calendar.MONTH, cal.get(Calendar.MONTH)-1);
		}
		for(int i=0;i<months.length;i++){
			System.out.println(months[i]);
		}
	}

輸出結果

2018-2
2018-3
2018-4
2018-5
2018-6
2018-7
2018-8
2018-9
2018-10
2018-11
2018-12
2019-1

可根據自己的需求進行改寫