仅从multiply if语句中打印一条错误消息

Question

我有一个检查输入日期的月，日，年是否正确的方法，该方法正常工作，但如果输入的日期月/年/日无效，则打印错误消息每个检查（月/日/年）都是错误的。我只有一条错误信息，而不是全部三条。

这是我所拥有的方法的代码：

  //Check to see if the date is valid
  public static boolean isValid(int day, int month, int year){

     boolean monthValid, yearValid, dayValid;
     boolean check = true;
     int dayNumber = 0;

        //check to see if the month is valid
        if(month <= 12 && month > 0){

           monthValid = true;

        }else{

           monthValid = false;
           System.out.println("Invalid month.");
           check = false;

        }

        //Check to see if the year is valid
        if (year <= 3000 && year >= 1){

           yearValid = true;

        }else{

           yearValid = false;
           System.out.println("Invalid Year.");
           check = false;

        }

        //assigns month to a number
        if (month == JAN || month == MAR || month == MAY || month == JUL || month == AUG ||month == OCT || month == DEC){

           dayNumber = LONG;

        }else if (month == APR || month == JUN || month == SEP || month == NOV){

           dayNumber = SHORT;

        }else if (month == FEB && true == isLeapYear(year)){

           dayNumber = AKWARD;


        }else if( month == FEB){

           dayNumber = MINI;

        }

        //check to see if day is valid
        if (day < dayNumber && day > 0 || day == dayNumber){

           dayValid = true;

        }else if(day == AKWARD && false == isLeapYear(year)){

           System.out.println("Invalid day number for February for given year.");   
           check = false;

        }else if( day > dayNumber || day < 0){

           dayValid = false;
           System.out.println("Invalid day number for month.");
           check = false;
        }
  return check; 
  }

所以如果输入的日期是13/34/3001（MM / DD / YYYY） 输出是：

以三种数字格式输入日期，m / d / year：13/34/3001

月份无效。

年度无效。

月份的天数无效。

同样，我只需要在这三个中打印一条错误消息。

谢谢！

Answer 1

不是设置check = false，而是在写入错误消息时立即返回false：

yearValid = false;
System.out.println("Invalid Year.");
return false;

Answer 2

这最像是一个设计问题。它可以有多种解决方案。

Simple返回false，打印出第一条错误信息后就不会再进一步​​了。

否则使用stringbuffer，将所有错误消息添加到一个并打印出来。你的选择。

Answer 3

您可以使用例外兄弟。

将您的检查代码包装在try / catch中，并在出现错误时抛出异常。像这样：

          //Check to see if the date is valid
      public static boolean isValid(int day, int month, int year){

         boolean monthValid, yearValid, dayValid;
         boolean check = true;
         int dayNumber = 0;
         try{
            //check to see if the month is valid
            if(month <= 12 && month > 0){

               monthValid = true;

            }else{

               monthValid = false;
               throw new IllegalArgumentException("INVALID");
            }

            //Check to see if the year is valid
            if (year <= 3000 && year >= 1){

               yearValid = true;

            }else{

               yearValid = false;
               throw new IllegalArgumentException("INVALID");
            }

            //assigns month to a number
            if (month == JAN || month == MAR || month == MAY || month == JUL || month == AUG ||month == OCT || month == DEC){

               dayNumber = LONG;

            }else if (month == APR || month == JUN || month == SEP || month == NOV){

               dayNumber = SHORT;

            }else if (month == FEB && true == isLeapYear(year)){

               dayNumber = AKWARD;


            }else if( month == FEB){

               dayNumber = MINI;

            }

            //check to see if day is valid
            if (day < dayNumber && day > 0 || day == dayNumber){

               dayValid = true;

            }else if(day == AKWARD && false == isLeapYear(year)){

              throw new IllegalArgumentException("INVALID");
            }else if( day > dayNumber || day < 0){

               dayValid = false;
               throw new IllegalArgumentException("INVALID");
            }
       }catch(IllegalArgumentException e)
       {
         System.out.println("Invalid date.");
         return false;
       }
   return true; 
  }