如何在Java中将字节大小转换为人类可读的格式?
比如1024应该变成“1 Kb”，1024*1024应该变成“1 Mb”。
我有点厌倦了为每个项目写这个实用方法。在Apache Commons中有这样的静态方法吗?
当前回答
下面是一个快速，简单和可读的代码片段来实现这一点:
/**
* Converts byte size to human readable strings (also declares useful constants)
*
* @see <a href="https://en.wikipedia.org/wiki/File_size">File size</a>
*/
@SuppressWarnings("SpellCheckingInspection")
public class HumanReadableSize {
public static final double
KILO = 1000L, // 1000 power 1 (10 power 3)
KIBI = 1024L, // 1024 power 1 (2 power 10)
MEGA = KILO * KILO, // 1000 power 2 (10 power 6)
MEBI = KIBI * KIBI, // 1024 power 2 (2 power 20)
GIGA = MEGA * KILO, // 1000 power 3 (10 power 9)
GIBI = MEBI * KIBI, // 1024 power 3 (2 power 30)
TERA = GIGA * KILO, // 1000 power 4 (10 power 12)
TEBI = GIBI * KIBI, // 1024 power 4 (2 power 40)
PETA = TERA * KILO, // 1000 power 5 (10 power 15)
PEBI = TEBI * KIBI, // 1024 power 5 (2 power 50)
EXA = PETA * KILO, // 1000 power 6 (10 power 18)
EXBI = PEBI * KIBI; // 1024 power 6 (2 power 60)
private static final DecimalFormat df = new DecimalFormat("#.##");
public static String binaryBased(long size) {
if (size < 0) {
throw new IllegalArgumentException("Argument cannot be negative");
} else if (size < KIBI) {
return df.format(size).concat("B");
} else if (size < MEBI) {
return df.format(size / KIBI).concat("KiB");
} else if (size < GIBI) {
return df.format(size / MEBI).concat("MiB");
} else if (size < TEBI) {
return df.format(size / GIBI).concat("GiB");
} else if (size < PEBI) {
return df.format(size / TEBI).concat("TiB");
} else if (size < EXBI) {
return df.format(size / PEBI).concat("PiB");
} else {
return df.format(size / EXBI).concat("EiB");
}
}
public static String decimalBased(long size) {
if (size < 0) {
throw new IllegalArgumentException("Argument cannot be negative");
} else if (size < KILO) {
return df.format(size).concat("B");
} else if (size < MEGA) {
return df.format(size / KILO).concat("KB");
} else if (size < GIGA) {
return df.format(size / MEGA).concat("MB");
} else if (size < TERA) {
return df.format(size / GIGA).concat("GB");
} else if (size < PETA) {
return df.format(size / TERA).concat("TB");
} else if (size < EXA) {
return df.format(size / PETA).concat("PB");
} else {
return df.format(size / EXA).concat("EB");
}
}
}
注意:
上面的代码冗长而简单。 它不使用循环(循环应该只在您不知道在编译期间需要迭代多少次时使用) 它不会进行不必要的库调用(StringBuilder, Math等) 上面的代码是快速的，使用非常少的内存。基于在我个人的入门级云计算机上运行的基准测试，它是最快的(在这些情况下性能并不重要，但仍然如此) 以上代码是一个很好的答案的修改版本
其他回答
下面是从aioobe转换到Kotlin的转换:
/**
* https://stackoverflow.com/a/3758880/1006741
*/
fun Long.humanReadableByteCountBinary(): String {
val b = when (this) {
Long.MIN_VALUE -> Long.MAX_VALUE
else -> abs(this)
}
return when {
b < 1024L -> "$this B"
b <= 0xfffccccccccccccL shr 40 -> "%.1f KiB".format(Locale.UK, this / 1024.0)
b <= 0xfffccccccccccccL shr 30 -> "%.1f MiB".format(Locale.UK, this / 1048576.0)
b <= 0xfffccccccccccccL shr 20 -> "%.1f GiB".format(Locale.UK, this / 1.073741824E9)
b <= 0xfffccccccccccccL shr 10 -> "%.1f TiB".format(Locale.UK, this / 1.099511627776E12)
b <= 0xfffccccccccccccL -> "%.1f PiB".format(Locale.UK, (this shr 10) / 1.099511627776E12)
else -> "%.1f EiB".format(Locale.UK, (this shr 20) / 1.099511627776E12)
}
}
FileUtils。如果你的项目依赖于org.apache.commons.io, byteCountToDisplaySize(长尺寸)可以工作。
此方法的JavaDoc
我最近问了同样的问题:
格式文件大小为MB, GB等。
虽然没有开箱即用的答案，但我可以接受这个解决方案:
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 new DecimalFormat("#,##0.#").format(result) + " " + unit;
}
测试代码:
public static void main(final String[] args){
final long[] l = new long[] { 1l, 4343l, 43434334l, 3563543743l };
for(final long ll : l){
System.out.println(convertToStringRepresentation(ll));
}
}
输出(在我的德语地区):
1 B
4,2 KB
41,4 MB
3,3 GB
我已经打开了一个问题，要求谷歌番石榴的这个功能。也许有人愿意支持它。
private String bytesIntoHumanReadable(long bytes) {
long kilobyte = 1024;
long megabyte = kilobyte * 1024;
long gigabyte = megabyte * 1024;
long terabyte = gigabyte * 1024;
if ((bytes >= 0) && (bytes < kilobyte)) {
return bytes + " B";
} else if ((bytes >= kilobyte) && (bytes < megabyte)) {
return (bytes / kilobyte) + " KB";
} else if ((bytes >= megabyte) && (bytes < gigabyte)) {
return (bytes / megabyte) + " MB";
} else if ((bytes >= gigabyte) && (bytes < terabyte)) {
return (bytes / gigabyte) + " GB";
} else if (bytes >= terabyte) {
return (bytes / terabyte) + " TB";
} else {
return bytes + " Bytes";
}
}
使用下面的函数来获得确切的信息。它是基于atm_cashwithdraw概念生成的。
getFullMemoryUnit(): Total: [123 MB], Max: [1 GB, 773 MB, 512 KB], Free: [120 MB, 409 KB, 304 Bytes]
public static String getFullMemoryUnit(long unit) {
long BYTE = 1024, KB = BYTE, MB = KB * KB, GB = MB * KB, TB = GB * KB;
long KILO_BYTE, MEGA_BYTE = 0, GIGA_BYTE = 0, TERA_BYTE = 0;
unit = Math.abs(unit);
StringBuffer buffer = new StringBuffer();
if ( unit / TB > 0 ) {
TERA_BYTE = (int) (unit / TB);
buffer.append(TERA_BYTE+" TB");
unit -= TERA_BYTE * TB;
}
if ( unit / GB > 0 ) {
GIGA_BYTE = (int) (unit / GB);
if (TERA_BYTE != 0) buffer.append(", ");
buffer.append(GIGA_BYTE+" GB");
unit %= GB;
}
if ( unit / MB > 0 ) {
MEGA_BYTE = (int) (unit / MB);
if (GIGA_BYTE != 0) buffer.append(", ");
buffer.append(MEGA_BYTE+" MB");
unit %= MB;
}
if ( unit / KB > 0 ) {
KILO_BYTE = (int) (unit / KB);
if (MEGA_BYTE != 0) buffer.append(", ");
buffer.append(KILO_BYTE+" KB");
unit %= KB;
}
if ( unit > 0 ) buffer.append(", "+unit+" Bytes");
return buffer.toString();
}
我刚刚修改了facebookarchive-StringUtils的代码以获得以下格式。与使用apache.hadoop-StringUtils时得到的格式相同
getMemoryUnit(): Total: [123.0 MB], Max: [1.8 GB], Free: [120.4 MB]
public static String getMemoryUnit(long bytes) {
DecimalFormat oneDecimal = new DecimalFormat("0.0");
float BYTE = 1024.0f, KB = BYTE, MB = KB * KB, GB = MB * KB, TB = GB * KB;
long absNumber = Math.abs(bytes);
double result = bytes;
String suffix = " Bytes";
if (absNumber < MB) {
result = bytes / KB;
suffix = " KB";
} else if (absNumber < GB) {
result = bytes / MB;
suffix = " MB";
} else if (absNumber < TB) {
result = bytes / GB;
suffix = " GB";
}
return oneDecimal.format(result) + suffix;
}
以上方法的使用示例:
public static void main(String[] args) {
Runtime runtime = Runtime.getRuntime();
int availableProcessors = runtime.availableProcessors();
long heapSize = Runtime.getRuntime().totalMemory();
long heapMaxSize = Runtime.getRuntime().maxMemory();
long heapFreeSize = Runtime.getRuntime().freeMemory();
System.out.format("Total: [%s], Max: [%s], Free: [%s]\n", heapSize, heapMaxSize, heapFreeSize);
System.out.format("getMemoryUnit(): Total: [%s], Max: [%s], Free: [%s]\n",
getMemoryUnit(heapSize), getMemoryUnit(heapMaxSize), getMemoryUnit(heapFreeSize));
System.out.format("getFullMemoryUnit(): Total: [%s], Max: [%s], Free: [%s]\n",
getFullMemoryUnit(heapSize), getFullMemoryUnit(heapMaxSize), getFullMemoryUnit(heapFreeSize));
}
字节来获取上面的格式
Total: [128974848], Max: [1884815360], Free: [126248240]
为了以人类可读的格式显示时间，请使用函数millisToShortDHMS(长持续时间)。
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