判断时间的正则表达式
2020-03-16 21:14:55
供稿：网友
刚刚学习正则，正则正是很好很强大的东西。练习下，时间格式为“HH:mm:ss”或“HH:mm”，采用24小时制。
普通方法为，分离出小时、分钟、秒分别进行判断：
public static boolean timeCheck(String time, String owner) {
//检查时间字符串time是否满足格式“HH:mm:ss”或“HH:mm”，若不满足显示相应消息，并返回false
if(time.equals("")){
String msg = owner+" : "+"Time is EMPTY.";
MessageDialog.showError(Controller.getMainFrame(), msg);
return false;
}
int hours, minutes, seconds = 0;
StringTokenizer st = new StringTokenizer(time, ":");
int tokens = st.countTokens();
if (tokens != 3 && tokens != 2) {
String msg = owner+" : "+"Time " + time + " does not conform to the HH:mm:ss format, nor HH:mm format.";
MessageDialog.showError(Controller.getMainFrame(), msg);
return false;
}
String hourToken = st.nextToken();
try {
hours = Integer.parseInt(hourToken);
} catch (NumberFormatException nfe) {
String msg = owner+" : "+hourToken + " in " + time + " can not be parsed as hours.";
MessageDialog.showError(Controller.getMainFrame(), msg);
return false;
}
String minuteToken = st.nextToken();
try {
minutes = Integer.parseInt(minuteToken);
} catch (NumberFormatException nfe) {
String msg = owner+" : "+minuteToken + " in " + time + " can not be parsed as minutes.";
MessageDialog.showError(Controller.getMainFrame(), msg);
return false;
}
if(tokens == 3){
String secondToken = st.nextToken();
try {
seconds = Integer.parseInt(secondToken);
} catch (NumberFormatException nfe) {
String msg = owner+" : "+secondToken + " in " + time + " can not be parsed as seconds.";
MessageDialog.showError(Controller.getMainFrame(), msg);
return false;
}
}
if (hours < 0 || hours > 23) {
String msg = owner+" : "+"Specified hours: " + hours + ". Number of hours must be in the [0..23] range.";
MessageDialog.showError(Controller.getMainFrame(), msg);
return false;
}
if (minutes < 0 || minutes > 59) {
String msg = owner+" : "+"Specified minutes: " + minutes + ". Number of minutes must be in the [0..59] range.";
MessageDialog.showError(Controller.getMainFrame(), msg);
return false;
}
if (seconds < 0 || seconds > 59) {
String msg = owner+" : "+"Specified seconds: " + seconds + ". Number of seconds must be in the [0..59] range.";
MessageDialog.showError(Controller.getMainFrame(), msg);
return false;
}
return true;
}
正则方法为：
public static boolean timeCheck(String time, String owner) {
//检查时间字符串time是否满足格式“HH:mm:ss”，若不满足显示相应消息，并返回false
String regex = "(([01]//d)|(2[0-3])):[0-5]//d(:[0-5]//d)?";
if(!time.matches(regex)){
String msg = owner+" : "+"Time is INVALID.";
MessageDialog.showError(Controller.getMainFrame(), msg);
return false;
}
return true;
}
真是很好很强大啊！！不过上述正则“((2[0-3])|([01]/d)):[0-5]/d(:[0-5]/d)?”实现居然不能匹配“3:3:3”，郁闷！
将正则改为“((2[0-3])|([0-1]?/d)):[0-5]?/d(:[0-5]?/d)?”倒是可以匹配“3:3:3”这种了，但“3:65:34”显然是不对的，却又匹配出两个来，晕！
将正则改为“((2[0-3])|([0-1]?/d)):[0-5]?/d(:[0-5]?/d)”倒是可以匹配“3:3:3”，也能正确判断“3:65:34”，却又没法判断“3:34”这种格式了。唉~~~~
