java8 时间类 LocalDate 

LocalDate.now()  获取当前时间  格式为：yyyy-MM-dd

LocalDate.of()  "创建"时间类

date.getDayOfWeek()  获取星期几，返回枚举类（WEDNESDAY。。）

date.getDayOfWeek().getValue()  转成int类型

with(TemporalAdjusters.lastDayOfMonth()).getDayOfMonth();获取本月最后一天

minusDays(1);  减一天

plusDays(1); 增一天

getDayOfMonth()  获取本月中的一天

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		System.out.println("请输入年份");
		int year = sc.nextInt();
		System.out.println("请输入月份");
		int month = sc.nextInt();
		LocalDate date = LocalDate.of(year, month, 1);
		System.out.println(date);
		int week = date.getDayOfWeek().getValue();
		int lastDay = date.with(TemporalAdjusters.lastDayOfMonth()).getDayOfMonth();
		LocalDate nextDay = date.minusDays(1);
		System.out.println("一\t二\t三\t四\t五\t六\t日");
		for (int i = 1; i <= lastDay+week-1; i++) {
			if(i<week) {
				System.out.print("\t");
			}else {
				nextDay = nextDay.plusDays(1);
				System.out.print(nextDay.getDayOfMonth()+"\t");
			}
			if(i%7==0) {
				System.out.println();
			}
		}
		sc.close();
	}