I basically need to do the opposite of this:
How can I convert byte size into a human-readable format in Java?
Input: 10.0MB
Outpt: 10000000
CodePudding user response:
You can use an enum like this
public static void main(String[] args) {
System.out.println(10 * UNIT.calculateBytes("MB"));
}
enum UNIT {
B(1000), KB(1000), MB(1000), GB(1000), TB(1000);
private int timesThanPreviousUnit;
UNIT(int timesThanPreviousUnit) {
this.timesThanPreviousUnit = timesThanPreviousUnit;
}
public static long calculateBytes(String symbol) {
long inBytes = 1;
UNIT inputUnit = UNIT.valueOf(symbol);
UNIT[] UNITList = UNIT.values();
for (UNIT unit : UNITList) {
if (inputUnit.equals(unit)) {
return inBytes;
}
inBytes *= unit.timesThanPreviousUnit;
}
return inBytes;
}
}
CodePudding user response:
Based on HariHaravelan's answer
public enum Unit {
B(1), KB(1024), MB(1024*1024), GB((1024L*1024L*1024L)
;
private final long multiplier;
private Unit(long multiplier) {
this.multiplier = multiplier;
}
// IllegalArgumentException if the symbol is not recognized
public static long multiplier(String symbol) throws IllegalArgumentException {
return Unit.valueOf(symbol.toUpperCase()).multiplier;
}
}
to be used as in
long bytes = (long) (10.0 * Unit.multiplier("MB"))
for scientific units (KB = 1000), replace first line inside the enum
(underscore between digits are ignored by Java):
public enum Unit {
B(1), KB(1_000), MB(1_000_000), GB((1_000_000_000)
... rest as above
More units can be added as needed - up to the limit of long
, if more are required, the multiplier
declaration can be changed to BigDecimal
or double
according use case/requirement.