Question

我试图以24小时格式解析用户输入＆＃34; 12：00＆＃34;但是当我输入分钟数小于的时间时，我失去领先的0。进入＆＃34; 3：05＆＃34;返回＆＃34; 3：5 AM＆＃34;

public class TimeFormatException extends Exception {

    public TimeFormatException()                   // time format exception default error message
    {
        super("This is an incorrect time");
    }

    public TimeFormatException(String error)     // time format exception with parameters 
    {
        super(error);
    }

}

public class Clock24 extends TimeFormatException {

    private int hours;                        // instance variables
    private int min;
    private boolean isAM;

    public Clock24()                         // default clock24
    {
        this.hours = 0;
        this.min = 0;
        this.isAM = true;
    }

    public Clock24(int hours, int min)       // clock 24 with parameters
    { 
        this.hours = hours;
        this.min = min;
    }

    public int getHours()                   // accessor and mutator for hours
    {
        return hours;
    }

    public void setHours(int hours)
    {
        this.hours = hours;
    }

    public int getMin()                            // accessor and mutator for minutes
    {
        return min;
    }

    public void setMin(int min)
    {
        this.min = min;
    }

    public void setAM(boolean isAm)                         // mutator for boolean isAM check
    {
        this.isAM = isAM;
    }

    public void setTime(int hours, int min)throws TimeFormatException   //declare TimeFormatException
    {
        if(hours>24 || hours < 0)
        {
            System.out.println("Exception!: Hour is incorrect!");
        }
        else if(min>60 || min < 0)
        {
            System.out.println("Exception!: Minutes is incorrect!");
        }
        else
        {
            if(hours>=12)
            {
                hours-=12;
                this.isAM=false;
            }
            else this.isAM = true;

            this.hours = hours;
            this.min = min;
        }
    }

    public void setTime(String time) throws TimeFormatException             //declare TimeFormatException
    {
        String[] substring = time.split(":");  // split the time into two substrings which will be parsed into integers
        int hour = -1;                         // set hour and minute to a value clearly less than accepted values
        int minute = -1;

        try                                                // try parsing substrings into integers
        {
            hour = Integer.parseInt(substring[0]);                      
            minute = Integer.parseInt(substring[1]);

        }
        catch(NumberFormatException e)                   //if this isn't possible because of the format print an error
        {
            System.out.println("Exception!: Incorrect format!");
        }
        catch(ArrayIndexOutOfBoundsException e)         //error will also be printed if not enough numbers are typed 
        {
            System.out.println("Exception!: Incorrect format!");
        }

        this.setTime(hour,minute);                        //use hour and minutes as parameter to set the time
    }

    public void printTime()                               // print the time
    {
        String dt = "";
        if(this.isAM)
        {
            dt = "AM";
        }
        else
        {
            dt = "PM";
        }
        System.out.println(this.hours+":"+this.min+" "+dt);
    }
}

import java.util.*;
public class Clock24Driver {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Clock24 clock = new Clock24();
        Scanner keyboard = new Scanner(System.in);

        boolean quit = false;
        while(quit == false)
        {
            //Prompt the user
            System.out.println("Enter a time in the 24-hour notation or enter \"Exit\" to quit");
            //Gets the user input
            String input = keyboard.nextLine();
            if(input.equalsIgnoreCase("exit"))
            {
                System.out.println("Goodbye!");
                break;
            }
            try
            {
                clock.setTime(input);
                clock.printTime();
            }
            catch(TimeFormatException e)
            {
                System.out.println(e.getMessage());
            }
        }
    }


}

Answer 1

您已解析了这些值。 Java int不会保留其原始格式的解析（它是一种原始类型，而包装类型也不会这样做）。我建议您将printTime()重命名为toString()，我建议您使用String.format(String, Object...)和ternary ?:之类的

@Override
public String toString() {
    return String.format("%02d:%02d %s", this.hours, this.min, 
            (this.isAM) ? "AM" : "PM");
}

然后改变

clock.printTime();

到

System.out.println(clock);

Answer 2

更改打印时间的方式

public void printTime() // print the time
{
    String dt = "";
    if(this.isAM)
    {
        dt = "AM";
    }
    else
    {
        dt = "PM";
    }
    System.out.println(String.format("%02d:%02d %s", this.hours, this.min, dt);
}

如何使用前导0来解析Int？

2 个答案: