我必須保持程序基本,不要太花哨。以下是我的問題: 當我輸入日期「2013年11月31日」時,它返回「30天正常月份的錯誤日期輸入」。我明白這意味着我的If/Else語句和/或我的布爾表達式的結構有問題。但我似乎無法弄清楚這個問題。任何幫助表示讚賞,謝謝。在Java中使用我的Date Validation程序獲取不正確的結果
這裏是我的程序:
import java.util.Scanner;
public class DateValidation {
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
String date;
System.out.println("Please enter a date in the following format: mm/dd/yyyy ");
date = keyboard.next();
int month = Integer.parseInt(date.substring(0, 2));
int day = Integer.parseInt(date.substring(3, 5));
int year = Integer.parseInt(date.substring(6, 10));
boolean isLeapYear = ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0));
boolean thirtyMonth = (month == 9 || month == 4 || month == 5 || month == 10);
boolean regMonth = (month == 1 || month == 3 || month == 6 || month == 7 || month == 8 || month == 11 || month == 12);
if ((month <= 0) || (day <= 0) || (day >= 32)) {
System.out.println("You entered an incorrect month or day value");
}
if ((month == 2) && (isLeapYear == true) && (day > 0) && (day <= 29)) {
System.out.println("it's a leap year - the date is " + date);
System.exit(0);
} else if ((month == 2) && (isLeapYear == false) && (day > 0) && (day <= 28)) {
System.out.println("it's not a leap year - the date is " + date);
System.exit(0);
} else if (month == 2) {
System.out.println("Your input is invald. Non leap-years only have 28 days");
System.exit(0);
}
if ((thirtyMonth == true) && (day > 0) && (day <= 30)) {
System.out.println("This is a valid date for a 30 day month - here is the date " + date);
System.exit(0);
} else if ((thirtyMonth == true) && (day < 0) || (day >= 31)) {
System.out.println("Incorrect day input for a regular month with 30 days");
System.exit(0);
}
if ((regMonth) && (day > 0) && (day <= 31)) {
System.out.println("This is a valid date for a regular month with 31 days - here is the date " + date);
System.exit(0);
} else if ((regMonth) && (day < 0) && (day >= 32)) {
System.out.println("Incorrect day input for a regular month with 31 days");
System.exit(0);
}
}
}
你可能想嘗試[喬達](http://joda-time.sourceforge.net/)。另外,你爲什麼這樣做? – Jess 2013-03-08 02:43:17
不使用if(isLeapYear == true),使用if(isLeapYear)。同樣,使用if(!isLeapYear)代替if(isLeapYear == false) – ncmathsadist 2013-03-08 02:44:15
它有助於將值放入輸出消息中,例如System.out.println(day +「在30天內一個月內無效」); System.exit(0); – BevynQ 2013-03-08 02:51:50