我一直试图找到一个真正快速的方法来解析yyyy-mm-dd [hh:mm:ss]到一个Date对象。以下是我尝试过的3种方法,以及每种方法分析50,000个日期时间字符串所需的时间。
- castMethod1 takes 3673 ms
- castMethod2 takes 3812 ms
- castMethod3 takes 3931 ms
码:
- private function castMethod1(dateString:String):Date {
- if ( dateString == null ) {
- return null;
- }
- var year:int = int(dateString.substr(0,4));
- var month:int = int(dateString.substr(5,2))-1;
- var day:int = int(dateString.substr(8,2));
- if ( year == 0 && month == 0 && day == 0 ) {
- return null;
- }
- if ( dateString.length == 10 ) {
- return new Date(year,month,day);
- }
- var hour:int = int(dateString.substr(11,2));
- var minute:int = int(dateString.substr(14,2));
- var second:int = int(dateString.substr(17,2));
- return new Date(year,day,hour,minute,second);
- }
–
- private function castMethod2(dateString:String):Date {
- if ( dateString == null ) {
- return null;
- }
- if ( dateString.indexOf("0000-00-00") != -1 ) {
- return null;
- }
- dateString = dateString.split("-").join("/");
- return new Date(Date.parse( dateString ));
- }
–
- private function castMethod3(dateString:String):Date {
- if ( dateString == null ) {
- return null;
- }
- var mainParts:Array = dateString.split(" ");
- var dateParts:Array = mainParts[0].split("-");
- if ( Number(dateParts[0])+Number(dateParts[1])+Number(dateParts[2]) == 0 ) {
- return null;
- }
- return new Date( Date.parse( dateParts.join("/")+(mainParts[1]?" "+mainParts[1]:" ") ) );
- }
不,默认情况下,Date.parse不会处理破折号。而且我需要为“0000-00-00”之类的日期时间字符串返回null。
解决方法
我一直在使用以下snipplet来解析UTC日期字符串:
- private function parseUTCDate( str : String ) : Date {
- var matches : Array = str.match(/(\d\d\d\d)-(\d\d)-(\d\d) (\d\d):(\d\d):(\d\d)Z/);
- var d : Date = new Date();
- d.setUTCFullYear(int(matches[1]),int(matches[2]) - 1,int(matches[3]));
- d.setUTCHours(int(matches[4]),int(matches[5]),int(matches[6]),0);
- return d;
- }
只需删除时间部分,它应该适合您的需要:
- private function parseDate( str : String ) : Date {
- var matches : Array = str.match(/(\d\d\d\d)-(\d\d)-(\d\d)/);
- var d : Date = new Date();
- d.setUTCFullYear(int(matches[1]),int(matches[3]));
- return d;
- }
不知道速度,我没有在我的应用程序中担心。在我的机器上显着少于一秒的50K次迭代。