java中判断字符串是否日期格式的方法

/**
	 * 通过正则表达式检查是否符合时间格式
	 */
	@SuppressWarnings("unused")	private boolean checkTimeFormat(String validateDate) {		boolean flag = false;		if(StringUtils.isNotEmpty(validateDate)){
			String datePattern1 = "d{4}-d{2}-d{2}";  
			String datePattern2 = "^((d{2}(([02468][048])|([13579][26]))" 
	              + "[-/s]?((((0?[13578])|(1[02]))[-/s]?((0?[1-9])|([1-2][0-9])|" 
	              + "(3[01])))|(((0?[469])|(11))[-/s]?((0?[1-9])|([1-2][0-9])|(30)))|(0?2[-/s]?" 
	              + "((0?[1-9])|([1-2][0-9])))))|(d{2}(([02468][1235679])|([13579][01345789]))[-/s]?(" 
	              + "(((0?[13578])|(1[02]))[-/s]?((0?[1-9])|([1-2][0-9])|(3[01])))|(((0?[469])|(11))[-/s]?" 
	              + "((0?[1-9])|([1-2][0-9])|(30)))|(0?2[-/s]?((0?[1-9])|(1[0-9])|(2[0-8]))))))";  			
			if (validateDate != null) {  
		          Pattern pattern = Pattern.compile(datePattern1);  
		          Matcher match = pattern.matcher(validateDate);  
		          if (match.matches()) {  
		              pattern = Pattern.compile(datePattern2);  
		              match = pattern.matcher(validateDate);  
		              
		             // return match.matches();  
		              return flag = true;
		          }  
		          else {  
		              return flag;  
		          }  
		      } 
			
		}		
		return flag;
	}