Java平日输入验证

Question

有没有一种“更整洁”的方式来编写这段代码？我是一个简单的坚持者，这对我来说似乎有点太重复了。 （我将日期改为数字，以便我可以在自己的if语句中使用它们，如果有人想知道）有什么建议吗？

Scanner scanText = new Scanner(System.in); 

System.out.print("Enter Day: "); 
String weekday = scanText.nextLine(); 

int day = 0; 

if (weekday.equalsIgnorCase("Monday")) 
    day = 1; 
else if (weekday.equalsIgnorCase("Tuesday")) 
    day = 2; 
else if (weekday.equalsIgnorCase("Wednesday")) 
    day = 3; 
else if (weekday.equalsIgnorCase("Thursday")) 
    day = 4; 
else if (weekday.equalsIgnorCase("Friday")) 
    day = 5; 
else if (weekday.equalsIgnorCase("Saturday")) 
    day = 6; 
else if (weekday.equalsIgnorCase("Sunday")) 
    day = 7; 
else { 
    System.out.print("Error! Invalid day: "); 
    weekday = scanText.nextLine(); 
} 

Answer 1

如果你不使用JDK 1.8，这个代码可以帮助你：

 List<String> strDays = Arrays.asList("Monday", "Tuesday", "Wednesday", "Thusday", "Friday", "Saturday", "Sunday"); 

    String weekday = scanText.nextLine(); 

    int day = 0; 
    if(strDays.contains(weekday)) { 

     day = strDays.indexOf(weekday) + 1; 
    } else { 
     System.out.print("Error! Invalid day: "); 
     weekday = scanText.nextLine(); 
    } 

Answer 2

import java.io.*; 
import java.text.*; 
import java.util.*; 


public class DayofWeekExample { 

    public static int getIntDayOfWeek(String dayOfWeek) 
    { 
     try 
     { 
      DateFormat formatter ; 
      Date date ; 
      formatter = new SimpleDateFormat("EEE"); 
      date = (Date)formatter.parse(dayOfWeek); 
      GregorianCalendar g = new GregorianCalendar(); 
      g.setTime(date); 
      return g.get(Calendar.DAY_OF_WEEK); 
     } 
     catch (ParseException e) 
     { 
      System.out.println("Exception :"+e); 
     } 
     return 0; 
    } 

    public static void main(String[] args) throws IOException { 
     // Beginnig day is Sunday 

     Scanner scanText = new Scanner(System.in); 

     System.out.print("Enter Day: "); 
     String weekday = scanText.nextLine(); 

     System.out.println("-> " + getIntDayOfWeek(weekday)); 


    } 
} 

一周的第一天，从当前区域设置的。如果您未设置日历的区域设置（Calendar.getInstance(Locale)或new GregorianCalendar(Locale)），则它将使用系统的默认设置。

Answer 3

因为你基本上是映射String值的int价值，我认为，它的Map一个典型的使用情况。您可以编写类似下面（一个缺点是，你必须初始化Map但可以被封装为更好的可读性）

Scanner scanText = new Scanner(System.in); 

     System.out.print("Enter Day: "); 
     String weekday = scanText.nextLine(); 

     int day = 0; 
     Map<String,Integer> day_of_week=new HashMap<String,Integer>(); 
     day_of_week.put("MONDAY", 1); 
     day_of_week.put("TUESDAY", 2); 
     day_of_week.put("WEDNESDAY", 3); 
     day_of_week.put("THURSDAY", 4); 
     day_of_week.put("FRIDAY", 5); 
     day_of_week.put("SATURDAY", 6); 
     day_of_week.put("SUNDAY", 7); 

     if(day_of_week.containsKey(weekday.toUpperCase())){ 
      day = day_of_week.get(weekday.toUpperCase()).intValue(); 
     }else{ 
      System.out.print("Error! Invalid day: "); 
       weekday = scanText.nextLine(); 
     } 

我相信你一定以为会比较部位从else块读值后再次。