Question

我在发布这个问题之前试图找到一个类似的答案，但我找不到一个。我应该计算并显示总天数，然后是月数和天数从现在开始（当程序运行时）到人的下一个生日（没有闰年）。这是我的代码：

import java.util.Scanner;
import java.text.*;
import java.lang.System;
import java.util.Date;

public class CSCD210Lab3
{
   public static void main (String [] args)
   {
      Scanner userInput = new Scanner(System.in);

      //Declare Variables

      String nameFirst;
      char firstLetter;
      String nameMiddle;
      String nameLast;
      char lastLetter;
      String genders;
      String genderName;
      String nameReplace;

      //Get User Input
      System.out.print("Please Enter Your Full Name(Including Middle Name): ") ;
      nameFirst = userInput.next();
      nameMiddle = userInput.next();
      nameLast = userInput.next();
      firstLetter = nameFirst.charAt(0);
      lastLetter = nameLast.charAt(nameLast.length()-1);
      userInput.nextLine() ;

      System.out.print("Please Enter Your Birthday in the Following Format: MM/DD/YYYY: ") ;
      userInput.nextLine() ;

      DateFormat dateFormat = new SimpleDateFormat("MM/dd/yyyy");
      Date date = new Date();

      System.out.print("Please Enter Your Gender as M or F: ") ;
      genders = userInput.next();
      char gender = genders.charAt(0);
      genderName = nameFirst + " " + nameMiddle + " " + nameLast;
      nameReplace = genderName.replaceAll(genders, "?");
      userInput.nextLine();


      System.out.println();
      System.out.println("The First Letter of Your First Name is: " + firstLetter) ;
      System.out.println("The Last Letter of Your Name is: "+ lastLetter);
      System.out.println("Your Middle Name is: " + nameMiddle);
      System.out.println("Your Name With the Last Name First is: "+ nameLast + ", "+ nameFirst + " " +nameMiddle);
      System.out.println("Today's Date is: "+dateFormat.format(date));
      System.out.println("Your Name With The Letter of Your Gender Replacing the Same Letters In Your     Name is: "+ nameReplace);

   }
}

我们还没有被教过使用像Jodatime这样的东西，所以这不是一个选择。有什么方法可以计算出来？

更新

我已经找到了计算剩余天数的方法，但我遇到了一个相当有趣的错误。这是输入生日的提示后的更新代码，以及更新的变量列表：

String nameFirst;
char firstLetter;
String nameMiddle;
String nameLast
char lastLetter;
String genders;
String genderName;
String nameReplace;
String birthMonth;
String birthDate;
String birthYear;
long birthMillis;
long systemMillis;
long diffMillis;
int daysFromMillis;
int birthMonthInt;
int birthDayInt;
int birthYearInt;

System.out.print("Please Enter Your Birthday in the Following Format: MM DD YYYY: ") ;
      birthMonth = userInput.next();
      birthDate = userInput.next();
      birthYear = userInput.next();
      birthMonthInt = Integer.parseInt(birthMonth);
      birthDayInt = Integer.parseInt(birthDate);
      birthYearInt = Integer.parseInt(birthYear);
      Calendar myCalendar = Calendar.getInstance();
      myCalendar.set(birthYearInt, birthDayInt, birthYearInt);
      birthMillis = myCalendar.getTimeInMillis();
      systemMillis = System.currentTimeMillis();
      diffMillis = (systemMillis - birthMillis);
      daysFromMillis = (int)(diffMillis / (86400000));
      userInput.nextLine() ;

当我在打印声明中调用daysFromMillis时，如果我在02/17/1993的生日那天进入，我将得到＃34;你的生日是5435天的回答。＆＃34;我做错了什么？

Answer 1

大多数人会同意Date类几乎是一场灾难......也许使用其他现有的标准类Calendar可以帮到你？并不是说它不是灾难，而是因为你没有在Joda-Time中获知java.time package或新的Java 8（由JSR 310定义，受到Joda-Time的启发）标准的8-Java之前没有太多明智的选择。

请查看另一个问题的Soumyarup Dasgupta’s answer，了解一个不太快但很简单的方法，即只使用其add method和一个简单循环查找两个Calendar实例之间的天数。同样的逻辑也将持续数月。日历有一个set method to manipulate individual fields - 以及相应的get method，使用这些功能并从链接代码中获取灵感应该可以帮助您入门。

计算用户输入日期Java的剩余天数？

1 个答案: