Question

我在尝试编写正确的代码时遇到问题，以测试键盘中的字符串是否包含正确月份的有效日期，每个特定月份的天数以及格式mm / dd / yyyy以及闰年的调整是我到目前为止所做的，我不认为我甚至接近，但任何帮助将不胜感激。提前致谢

/* read a date from a string from the keyboard to determine if date is in mm/dd/yyyy format.

 */
import java.util.Scanner;

public class DateFormat

{

public static void main(String [ ] args)

{

   Scanner inp = new Scanner(System.in);

   System.out.println("Enter the date in mm/dd/yyyy format. ");

    int mm;

    int dd;

    int yy;

    int date = inp.nextInt();

    boolean isLeapYear;

        if ((mm <1) && (mm >12))

            System.out.println( date + " is not valid month must be between 1 and 12.");
       if (( mm = 4) &&  ( dd <=30 ))
            System.out.println( date + " is a valid date."); 
            }
                else 
                    System.out.println(date + " is not valid date must have 30 or less days. ");
         if (date = mm + "/" + dd + "/" + yy);
            System.out.println( date + " is a valid date format. ");
        }
        else{
            System.out.println( date + " is not valid must be in dd/mm/yyyy format.");

            if (yy %100 ==0) {
          if (yy % 400 ==0){
              isLeapYear = true;
          }    
          else{
              isLeapYear = false;
          }   
        }  
        else{
            if (yy %4 ==0){
             isLeapYear = true;
            }
            else{
             isLeapYear = false;

           if (isLeapYear)
           if ((mm ==2) && (dd <= 29 ))
            System.out.println(date + " is a valid date.");
           }
           else{
               System.out.println( date + "is not valid month must have 29 days or less.");
            if ((mm ==2) && (dd<=28))
                System.out.println( date + "  is a valid date.");
            }
            else{
                System.out.println( date + "is not valid must have 28 days or less. ");

Answer 1

我认为这会有所帮助： http://www.javadb.com/check-if-a-string-is-a-valid-date

基本上，您不需要编写代码来检查日期是否有效。例如，您可以使用java.text包中的SimpleDataFormat类。

public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    System.out.print("Valid? " + isValidDate(scanner.nextLine()));
}

private boolean isValidDate(String inDate) {

    if (inDate == null)
      return false;

    //set the format to use as a constructor argument
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");

    if (inDate.trim().length() != dateFormat.toPattern().length())
      return false;

    dateFormat.setLenient(false);

    try {
      //parse the inDate parameter
      dateFormat.parse(inDate.trim());
    }
    catch (ParseException pe) {
      return false;
    }
    return true;
  }

测试键盘输入字符串是否具有有效的日期和格式

1 个答案: