如何在java 8中使用String.format？ [英] How to use String.format in java 8?

问题描述

今天我在java 8的eclipse Kepler中编写了一个简单的程序。实际上，我从一些视频教程中复制了它。在该教程中，它运行，但在我的计算机中它没有。错误行是

Today I wrote a simple program in eclipse Kepler in java 8. Actually, I copied it from some video tutorial. In that tutorial, it ran, but in my computer it didn't. Error line is

 String.format("%02d:%02d:%02d",hour,minute,second);

我不明白这里的错误是什么。
它突出显示类型 String 中的方法 format（String，object []）不适用于参数（String，int，int，int）

I don't understand what the error is here. It highlights the method format(String,object[]) in the type String are not applicable for the argument(String, int, int, int)

public class Demo {

private int hour;
    private int second;
    private int minute;

    public void setTime(int h,int m,int s){
        hour=((h>=0 && h<24)?h:0);
        minute=((m>=0 && m<60)?m:0);
        second=((s>=0 && s<60)?s:0);
    }

    public String railwayTime(){
        return String.format("%02d:%02d:%02d",hour,minute,second);//error in this line
    }

    public String regular(){
        return String.format("%02d:%02d:%02d %s",((hour==0 ||hour==24)?12:(hour%12)), minute, second, (hour>=12)?"AM":"PM");//error in this line
    }
}

public class ShowTime {
    public static void main(String[] args){
        Demo d=new Demo();
        System.out.println(d.railwayTime());
        System.out.println(d.regular());
    }
}

推荐答案

异常要求您输入数组而不是逗号分隔字符串：

The exception asks you for an array instead comma-sepparated strings:

// incorrect
String.format("%02d:%02d:%02d",hour,minute,second);

// fast but correct
Object[] data = { hour, minute, second };
String.format("%02d:%02d:%02d", data);

但实际上，方法 format（String，object []）在 String 中不存在，它是： format（String pattern，Object ... arguments）什么应该用逗号，。您的语法有些内容，但在显示的代码中没有。

But actually, method format(String,object[]) does not exists in String, it is: format(String pattern, Object... arguments) what should work with commas ,. There is something with your syntax, but not in the shown code.

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