Java後端獲取指定某年某月的第一天和最後一天

獲取指定的年月的第一天：

	public static String getFisrtDayOfMonth(int year,int month){
	    Calendar cal = Calendar.getInstance();
	    //設置年份
	    cal.set(Calendar.YEAR,year);
	    //設置月份
	    cal.set(Calendar.MONTH, month-1);
	    //獲取某月最小天數
	    int firstDay = cal.getActualMinimum(Calendar.DAY_OF_MONTH);
	    //設置日曆中月份的最小天數
	    cal.set(Calendar.DAY_OF_MONTH, firstDay);
	    //格式化日期
	    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
	    String firstDayOfMonth = sdf.format(cal.getTime());
	    
	    return firstDayOfMonth;
	 }

獲取指定的年月的最後一天：

	public static String getLastDayOfMonth(int year,int month) {  
		Calendar cal = Calendar.getInstance();  
		//設置年份  
		cal.set(Calendar.YEAR,year);  
		//設置月份  
		cal.set(Calendar.MONTH, month-1);  
		//獲取某月最大天數  
		int lastDay = cal.getActualMaximum(Calendar.DAY_OF_MONTH);  
		//設置日曆中月份的最大天數  
		cal.set(Calendar.DAY_OF_MONTH, lastDay);  
		//格式化日期  
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");  
		String lastDayOfMonth = sdf.format(cal.getTime());  
		
		return lastDayOfMonth;  
	}