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?
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
datasize至少在计算中可以满足这个需求。那么一个简单的装饰器就可以了。
其他回答
public String humanReadable(long size) {
long limit = 10 * 1024;
long limit2 = limit * 2 - 1;
String negative = "";
if(size < 0) {
negative = "-";
size = Math.abs(size);
}
if(size < limit) {
return String.format("%s%s bytes", negative, size);
} else {
size = Math.round((double) size / 1024);
if (size < limit2) {
return String.format("%s%s kB", negative, size);
} else {
size = Math.round((double)size / 1024);
if (size < limit2) {
return String.format("%s%s MB", negative, size);
} else {
size = Math.round((double)size / 1024);
if (size < limit2) {
return String.format("%s%s GB", negative, size);
} else {
size = Math.round((double)size / 1024);
return String.format("%s%s TB", negative, size);
}
}
}
}
}
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)
}
}
我使用了一个比公认答案稍作修改的方法:
public static String formatFileSize(long bytes) {
if (bytes <= 0)
return "";
if (bytes < 1000)
return bytes + " B";
CharacterIterator ci = new StringCharacterIterator("kMGTPE");
while (bytes >= 99_999) {
bytes /= 1000;
ci.next();
}
return String.format(Locale.getDefault(), "%.1f %cB", bytes / 1000.0, ci.current());
}
因为我想看到另一个输出:
SI
0: <--------- instead of 0 B
27: 27 B
999: 999 B
1000: 1.0 kB
1023: 1.0 kB
1024: 1.0 kB
1728: 1.7 kB
110592: 0.1 MB <--------- instead of 110.6 kB
7077888: 7.1 MB
452984832: 0.5 GB <--------- instead of 453.0 MB
28991029248: 29.0 GB
实际上,兆字节已经足够人类阅读了。
long l = 1367343104l;
String s = String.format("%dm", l / 1024 / 1024);
1304米
字节单位允许你这样做:
long input1 = 1024;
long input2 = 1024 * 1024;
Assert.assertEquals("1 KiB", BinaryByteUnit.format(input1));
Assert.assertEquals("1 MiB", BinaryByteUnit.format(input2));
Assert.assertEquals("1.024 KB", DecimalByteUnit.format(input1, "#.0"));
Assert.assertEquals("1.049 MB", DecimalByteUnit.format(input2, "#.000"));
NumberFormat format = new DecimalFormat("#.#");
Assert.assertEquals("1 KiB", BinaryByteUnit.format(input1, format));
Assert.assertEquals("1 MiB", BinaryByteUnit.format(input2, format));
我写了另一个叫做storage-units的库,它允许你这样做:
String formattedUnit1 = StorageUnits.formatAsCommonUnit(input1, "#");
String formattedUnit2 = StorageUnits.formatAsCommonUnit(input2, "#");
String formattedUnit3 = StorageUnits.formatAsBinaryUnit(input1);
String formattedUnit4 = StorageUnits.formatAsBinaryUnit(input2);
String formattedUnit5 = StorageUnits.formatAsDecimalUnit(input1, "#.00", Locale.GERMAN);
String formattedUnit6 = StorageUnits.formatAsDecimalUnit(input2, "#.00", Locale.GERMAN);
String formattedUnit7 = StorageUnits.formatAsBinaryUnit(input1, format);
String formattedUnit8 = StorageUnits.formatAsBinaryUnit(input2, format);
Assert.assertEquals("1 kB", formattedUnit1);
Assert.assertEquals("1 MB", formattedUnit2);
Assert.assertEquals("1.00 KiB", formattedUnit3);
Assert.assertEquals("1.00 MiB", formattedUnit4);
Assert.assertEquals("1,02 kB", formattedUnit5);
Assert.assertEquals("1,05 MB", formattedUnit6);
Assert.assertEquals("1 KiB", formattedUnit7);
Assert.assertEquals("1 MiB", formattedUnit8);
如果你想强制某个单位,可以这样做:
String formattedUnit9 = StorageUnits.formatAsKibibyte(input2);
String formattedUnit10 = StorageUnits.formatAsCommonMegabyte(input2);
Assert.assertEquals("1024.00 KiB", formattedUnit9);
Assert.assertEquals("1.00 MB", formattedUnit10);