判斷時間的正則表達式
2020-03-16 21:14:55
供稿：網友
剛剛學習正則，正則正是很好很強大的東西。練習下，時間格式為“HH:mm:ss”或“HH:mm”，采用24小時制。
普通方法為，分離出小時、分鐘、秒分別進行判斷：
public static boolean timeCheck(String time, String owner) {
//檢查時間字符串time是否滿足格式“HH:mm:ss”或“HH:mm”，若不滿足顯示相應消息，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;
}
正則方法為：
public static boolean timeCheck(String time, String owner) {
//檢查時間字符串time是否滿足格式“HH:mm:ss”，若不滿足顯示相應消息，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;
}
真是很好很強大啊！！不過上述正則“((2[0-3])|([01]/d)):[0-5]/d(:[0-5]/d)?”實現居然不能匹配“3:3:3”，郁悶！
將正則改為“((2[0-3])|([0-1]?/d)):[0-5]?/d(:[0-5]?/d)?”倒是可以匹配“3:3:3”這種了，但“3:65:34”顯然是不對的，卻又匹配出兩個來，暈！
將正則改為“((2[0-3])|([0-1]?/d)):[0-5]?/d(:[0-5]?/d)”倒是可以匹配“3:3:3”，也能正確判斷“3:65:34”，卻又沒法判斷“3:34”這種格式了。唉~~~~
