格式文件大小为MB，GB等 [英] Format file size as MB, GB etc

问题描述

eg

  1L ==> 1B; 
 1024L ==> 1 KB; 
 2537253L ==> 2.3 MB
  

等。

我找到了这个以前的答案，我没有找到满意的

我已经想出了自己的解决方案，它有类似的缺点：$ b​​
$ b pre code private静态最终长K = 1024;
private static final long M = K * K;
private static final G = M * K;
private static final long T = G * K;

public static String convertToStringRepresentation（final long value）{
final long [] dividers = new long [] {T，G，M，K，1};
final String [] units = new String [] {TB，GB，MB，KB，B};
if（value <1）
throw new IllegalArgumentException（Invalid file size：+ value）;
String result = null;
for（int i = 0; i< divrs.length; i ++）{
final long divider = divider [i];
if（value> = divider）{
result = format（value，divider，units [i]）;
break;
}
}
返回结果;


private static String格式（最终长整型值，
最终长整型数，
最终整型单位）{
最终双重结果=
divider> 1？ （双）值/（双）分频器：（双）值;
return String.format（％。1f％s，Double.valueOf（result），unit）;
}

主要问题是我对Decimalformat和/或String.format知之甚少。
我想1024L，1025L等映射到 1 KB 而不是 1.0 KB 。

所以，有两种可能：

1. 我宁愿选择一个好的out-of-如apache commons或google guava。


2. 如果没有，有人可以告诉我如何摆脱.0部分（不采用字符串替换和正则表达式，我可以自己做）

解决方案

  public static String readableFileSize（long size）{
 if（size< = 0）返回0; 
 final String [] units = new String [] {B，kB，MB，GB，TB}; 
 int digitGroups =（int）（Math.log10（size）/Math.log10（1024））; 
返回新的DecimalFormat（＃，## 0。＃）。format（size / Math.pow（1024，digitGroups））++ units [digitGroups]; 
 
 
 
 $ b $ p $这样可以达到1000 TB ....程序很短！
 
I need to display a file size as String using sensible units.

e.g.
1L ==> "1 B";
1024L ==> "1 KB";
2537253L ==> "2.3 MB"
etc.

I found this previous answer, which I didn't find satisfactory

I have come up with my own solution which has similar shortcomings:
private static final long K = 1024;
private static final long M = K * K;
private static final long G = M * K;
private static final long T = G * K;

public static String convertToStringRepresentation(final long value){
    final long[] dividers = new long[] { T, G, M, K, 1 };
    final String[] units = new String[] { "TB", "GB", "MB", "KB", "B" };
    if(value < 1)
        throw new IllegalArgumentException("Invalid file size: " + value);
    String result = null;
    for(int i = 0; i < dividers.length; i++){
        final long divider = dividers[i];
        if(value >= divider){
            result = format(value, divider, units[i]);
            break;
        }
    }
    return result;
}

private static String format(final long value,
    final long divider,
    final String unit){
    final double result =
        divider > 1 ? (double) value / (double) divider : (double) value;
    return String.format("%.1f %s", Double.valueOf(result), unit);
}
The main problem is my limited knowledge of Decimalformat and / or String.format.
I would like 1024L, 1025L etc to map to 1 KB rather than 1.0 KB.

So, two possibilities:

I would prefer a good out-of-the-box solution in a public library like apache commons or google guava.
If there isn't, can someone show me how to get rid of the '.0' part (without resorting to string replacement and regex, I can do that myself)

解决方案
public static String readableFileSize(long size) {
    if(size <= 0) return "0";
    final String[] units = new String[] { "B", "kB", "MB", "GB", "TB" };
    int digitGroups = (int) (Math.log10(size)/Math.log10(1024));
    return new DecimalFormat("#,##0.#").format(size/Math.pow(1024, digitGroups)) + " " + units[digitGroups];
}
This will work up to 1000 TB.... and the program is short!

                        
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