使用Java的转换器从数秒到数天，数小时，数分钟和数秒的问题

Question

我正在为编程类执行此操作，当我在jGrasp中编译程序时，不断出现这些错误：

TimeCalculator.java:94: error: variable dblMinutes might not have been initialized
            + timeFormat.format(dblMinutes) + " minutes, and " + timeFormat.format(dblSecondsAfterMinutes) + " seconds.");
                                ^
TimeCalculator.java:94: error: variable dblSecondsAfterMinutes might not have been initialized
            + timeFormat.format(dblMinutes) + " minutes, and " + timeFormat.format(dblSecondsAfterMinutes) + " seconds.");
                                                                                   ^
TimeCalculator.java:98: error: variable dblMinutes might not have been initialized
            JOptionPane.showMessageDialog(null, "There are " + timeFormat.format(dblHours) + " hours, " + timeFormat.format(dblMinutes) + " minutes, and " 
                                                                                                                            ^
TimeCalculator.java:99: error: variable dblSecondsAfterMinutes might not have been initialized
            + timeFormat.format(dblSecondsAfterMinutes) + " seconds.");
                                ^
TimeCalculator.java:101: error: variable dblMinutes might not have been initialized
        else if (dblMinutes >= 1)
                 ^
TimeCalculator.java:102: error: variable dblSecondsAfterMinutes might not have been initialized
            JOptionPane.showMessageDialog(null, "There are " + timeFormat.format(dblMinutes) + " minutes and " + timeFormat.format(dblSecondsAfterMinutes) + " seconds.");  
                                                                                                                                   ^
6 errors

我的程序应该接受用户输入（以秒为单位的数量）并将其转换为天，小时，分钟和秒。 然后应显示最终金额。

到目前为止，这是我的代码：

    /*
This program prompts the user to enter an amount of seconds.
When the user enters an amount, it is stored in a variable and
calculated to how many days, hours, minutes, and seconds there 
are in the given amount of seconds. The information is then 
output for the user to read.

60 seconds = 1 minute
3600 seconds = 1 hour
86400 seconds = 1 day
*/

import javax.swing.JOptionPane;
import java.text.DecimalFormat;

public class TimeCalculator
{
    public static void main(String[] args)
    {
        DecimalFormat timeFormat = new DecimalFormat("#0.#");//used for formatting output

        //declaring needed variables
        String strStartingSeconds;
        double dblStartingSeconds, dblMinutes, dblHours, dblDays, dblSecondsAfterDays, dblSecondsAfterHours, dblSecondsAfterMinutes;

        //get input from user for amount of seconds
        strStartingSeconds = JOptionPane.showInputDialog("Enter the amount of seconds: ");

        //convert input to a double
        dblStartingSeconds = Double.parseDouble(strStartingSeconds);

        if (dblStartingSeconds >= 86400)//check to see if it is one day or more
        {
            dblDays = dblStartingSeconds / 86400;//find how many days
            dblSecondsAfterDays = dblStartingSeconds % 86400;//calculate how many seconds are left by finding the remainder

            if (dblSecondsAfterDays >= 3600)//check to see if there is one hour or more
            {
                dblHours = dblSecondsAfterDays / 3600;//find how many hours
                dblSecondsAfterHours = dblSecondsAfterDays % 3600;//calculate how many seconds are left by finding the remainder

                if (dblSecondsAfterHours >= 60)//Check to see if there is one or more minutes
                {
                    dblMinutes = dblSecondsAfterHours / 60;//Calculate how many minutes
                    dblSecondsAfterMinutes = dblSecondsAfterHours % 60;//calculate how many seconds are left by finding the remainder
                }
                else
                {
                    dblMinutes = 0;//If there wasn't enough seconds, assign minutes as 0
                }
            }
            else
                dblHours = 0;//If there wasn't enough hours, assign hours as 0
        }
        else
        {
            dblDays = 0;//assign days as 0 since there wasn't enough seconds

            if (dblStartingSeconds >= 3600)//check to see if there is one hour or more
            {
                dblHours = dblStartingSeconds / 3600;//find how many hours
                dblSecondsAfterHours = dblStartingSeconds % 3600;//calculate how many seconds are left by finding the remainder

                if (dblSecondsAfterHours >= 60)//Check to see if there is one or more minutes
                {
                    dblMinutes = dblSecondsAfterHours / 60;//Calculate how many minutes
                    dblSecondsAfterMinutes = dblSecondsAfterHours % 60;//calculate how many seconds are left by finding the remainder
                }
                else
                {
                    dblMinutes = 0;//assign minutes as 0 since there wasn't enough seconds
                }
            }
            else
            {               
                dblHours = 0;//assign hours as 0 since there wasn't enough hours

                if (dblStartingSeconds >= 60)//Check to see if there is one or more minutes
                {
                    dblMinutes = dblStartingSeconds / 60;//Calculate how many minutes
                    dblSecondsAfterMinutes = dblStartingSeconds % 60;//calculate how many seconds are left by finding the remainder
                }
                else
                {                   
                    dblMinutes = 0;//Assign minutes as 0 since there wasn't enough seconds                          
                    JOptionPane.showMessageDialog(null, "There are " + timeFormat.format(dblStartingSeconds) + " seconds.");//Displays how many seconds there was
                }
            }
        }
        //Display the correct amount of time based on whether or not there was enough seconds for days, hours, or minutes
        if (dblDays >= 1)
        {
            JOptionPane.showMessageDialog(null, "There are " + timeFormat.format(dblDays) + " days, " + timeFormat.format(dblHours) + " hours, " 
            + timeFormat.format(dblMinutes) + " minutes, and " + timeFormat.format(dblSecondsAfterMinutes) + " seconds.");
        }
        else if (dblHours >= 1)
        {
            JOptionPane.showMessageDialog(null, "There are " + timeFormat.format(dblHours) + " hours, " + timeFormat.format(dblMinutes) + " minutes, and " 
            + timeFormat.format(dblSecondsAfterMinutes) + " seconds.");
        }
        else if (dblMinutes >= 1)
            JOptionPane.showMessageDialog(null, "There are " + timeFormat.format(dblMinutes) + " minutes and " + timeFormat.format(dblSecondsAfterMinutes) + " seconds.");  
        else
            JOptionPane.showMessageDialog(null, "There are " + timeFormat.format(dblStartingSeconds) + " seconds.");

        System.exit(0);//close application
    }
}

我没有开玩笑，花了几个小时仔细研究，却找不到我做错了！ 我对编程还很陌生，所以任何事情都会有所帮助（我可能做过一些愚蠢而明显的事情，对于专业程序员而言）。

谢谢，-Cashe

Answer 1

double dblMinutes = 0;

在此处阅读有关初始化字段的信息： http : //docs.oracle.com/javase/tutorial/java/javaOO/initial.html

Answer 2

除了初始化问题之外，在处理时间单位转换时， java.util.concurrent.TimeUnit是您最好的朋友。