我知道我可以使用日期格式化程序,但我試圖學習。從掃描儀獲取輸入並生成有效日期
我試圖從Scanner
採取格式mm/dd/yyyy
的日期。當我爲這個月採取投入時,我遇到了麻煩。例如,如果我想要一月份,請按01並且monthInt
將其轉換爲1
而不是01
。
我也有我的一天的麻煩。當我輸入有效日期時,它會一直說無效的日期。我的if
聲明搞砸了嗎?如果你需要更多解釋,請問。感謝您的時間!
我的代碼:
System.out.println("Enter a date in the format mm/dd/yyyy");
String mm;
String dd;
String yyyy;
String January = null;
String February = null;
String March = null;
String April = null;
String May = null;
String June = null;
String July = null;
String August = null;
String September = null;
String October = null;
String November = null;
String December = null;
String month = null;
String date = null;
Scanner keyboard = new Scanner(System.in);
date = keyboard.next();
if (date.length() != 10) {
System.out.println("Format of date is wrong");
}
if (date.charAt(2) != '/') {
System.out.println("Must have/after mm");
}
if (date.charAt(5) != '/') {
System.out.println("Must have/after dd");
}
else if (date.length() == 10 && date.charAt(2) != '/' && date.charAt(5) != '/') {
System.out.println(date + " date is valid");
}
mm = date.substring(0, 1);
int monthInt = Integer.parseInt(mm);
if (monthInt == 1) {
month = January;
} else if (monthInt == 2) {
month = February;
} else if (monthInt == 3) {
month = March;
} else if (monthInt == 4) {
month = April;
} else if (monthInt == 5) {
month = May;
} else if (monthInt == 6) {
month = June;
} else if (monthInt == 7) {
month = July;
} else if (monthInt == 8) {
month = August;
} else if (monthInt == 9) {
month = September;
} else if (monthInt == 10) {
month = October;
} else if (monthInt == 11) {
month = November;
} else if (monthInt == 12) {
month = December;
} else {
System.out.println("Invalid Month");
}
if (monthInt < 0 || monthInt > 12) {
System.out.println("Invalid month");
}
dd = date.substring(3, 4);
int dayInt = Integer.parseInt(dd);
if (monthInt == 1 || monthInt == 3 || monthInt == 5 || monthInt == 7 || monthInt == 8 || monthInt == 10
|| monthInt == 12 && dayInt < 0 && dayInt > 31) {
System.out.println("Invalid day");
}
if (monthInt == 4 || monthInt == 6 || monthInt == 9 || monthInt == 11
&& dayInt < 0 && dayInt > 30) {
System.out.println("Invalid day");
}
if (monthInt == 2 && dayInt < 0 && dayInt > 28){
System.out.println("Invalid day");
}
哪幾天和這幾個月是ü得到錯誤? – DarkV1
刪除所有'String monthName = null'東西。它很混亂,沒有必要。相反,使用引號括住你的'month = monthName'代碼,使其成爲一個真正的字符串(例如'month =「January」') – Confiqure