B is the abbreviation of Byte, meaning byte; b is the abbreviation of bit, meaning bit; Kb is the kilobit, KB is the kilobyte; MB is the megabyte;
Conversion relationship:
1MB=1024KB=1024B*1024=1048576B；
8bit=1Byte；
1024KB=1MB；
1024MB=1GB；
1024GB=1TB；
About transmission rate and network speed:
We usually see that the transmission rate of the USB2.0 interface is 480mbps, so we naturally think that its speed is 480M/S. In fact, this is wrong. mbps is the abbreviation of mega bits per second, meaning Mb/S (megabits/second). The correct understanding should be: 60MB/S, and the conversion relationship is as above, which is a 1:8 relationship.
The 100M network speed usually refers to 100Mbps (1024 bits), which is converted into 12.5MB/S. Theoretically, the download speed can reach 12.5MB/S.
Calculation of hard disk capacity:
When manufacturers make hard disks, for the sake of calculation convenience, 1KB is only 1000Byte, 1MB is only 1000KB, and 1G is only 1000MB. . . . . . So, a 500G hard drive is actually only
500*1000*1000*1000/1024*1024*1024 = 465.66G
The general formula for estimating the size of a hard disk:
Hard disk appearance size (G) * 1000*1000*1000/1024*1024*1024=actual hard disk size (G)
/**
*
* @title
* @date January 7, 2019
* @author niuchang
* @param size
* @param old_unit File unit before conversion
* @param new_unit Converted file units
* @return
*/
public static long unitConvert(long size,String old_unit,String new_unit){
long new_size=0;
if ((old_unit) && (new_unit)) {
old_unit=old_unit.toLowerCase().trim();
new_unit=new_unit.toLowerCase().trim();
if (!old_unit.equals(new_unit)) {
if ((FILE_UNIT_BIT.equals(old_unit) || FILE_UNIT_BYTE.equals(old_unit)
|| FILE_UNIT_KB.equals(old_unit) || FILE_UNIT_MB.equals(old_unit)
|| FILE_UNIT_GB.equals(old_unit) || FILE_UNIT_TB.equals(old_unit))
&& (FILE_UNIT_BIT.equals(new_unit) || FILE_UNIT_BYTE.equals(new_unit)
|| FILE_UNIT_KB.equals(new_unit) || FILE_UNIT_MB.equals(new_unit)
|| FILE_UNIT_GB.equals(new_unit) || FILE_UNIT_TB.equals(new_unit))) {
if (isFileUnit(old_unit, new_unit)) {//Small unit to large unit
if (FILE_UNIT_BIT.equals(old_unit) && FILE_UNIT_KB.equals(new_unit)) {//Bit bit to kilobyte kb
size=size/8/1024;
}else if (FILE_UNIT_BIT.equals(old_unit) && FILE_UNIT_MB.equals(new_unit)) {//Bit bit to megabyte mb
size=size/8/1024/1024;
}else if (FILE_UNIT_BIT.equals(old_unit) && FILE_UNIT_GB.equals(new_unit)) {//Bit bit to gigabyte gb
size=size/8/1024/1024/1024;
}else if (FILE_UNIT_BYTE.equals(old_unit) && FILE_UNIT_KB.equals(new_unit)) {//Byte byte to kilobyte kb
size=size/1024;
}else if (FILE_UNIT_BYTE.equals(old_unit) && FILE_UNIT_MB.equals(new_unit)) {//Byte byte to megabyte mb
size=size/1024/1024;
}else if (FILE_UNIT_BYTE.equals(old_unit) && FILE_UNIT_GB.equals(new_unit)) {//Byte byte to gigabyte gb
size=size/1024/1024/1024;
}else if (FILE_UNIT_KB.equals(old_unit) && FILE_UNIT_MB.equals(new_unit)) {//Kneimeter kb to megabyte mb
size=size/1024;
}else if (FILE_UNIT_KB.equals(old_unit) && FILE_UNIT_GB.equals(new_unit)) {//Key byte kb to Gigabyte gb
size=size/1024/1024;
}else if (FILE_UNIT_MB.equals(old_unit) && FILE_UNIT_GB.equals(new_unit)) {//Megabyte mb to Gigabyte gb
size=size/1024;
}else{//More type conversions
boolean isRe=false;
double sized=size;
if (FILE_UNIT_BIT.equals(old_unit)) {//Bit bit to byte byte
sized=sized/8;
old_unit=FILE_UNIT_BYTE;
}
isRe=(isRe || old_unit.equals(new_unit))?true:false;
if (FILE_UNIT_BYTE.equals(old_unit) && !isRe) {//Byte byte to kilobyte kb
sized=sized/1024;
old_unit=FILE_UNIT_KB;
}
isRe=(isRe || old_unit.equals(new_unit))?true:false;
if (FILE_UNIT_KB.equals(old_unit) && !isRe) {//Key byte kb to megabyte mb
sized=sized/1024;
old_unit=FILE_UNIT_MB;
}
isRe=(isRe || old_unit.equals(new_unit))?true:false;
if (FILE_UNIT_MB.equals(old_unit) && !isRe) {//Megabyte mb to Gigabyte gb
sized=sized/1024;
old_unit=FILE_UNIT_GB;
}
isRe=(isRe || old_unit.equals(new_unit))?true:false;
if (FILE_UNIT_GB.equals(old_unit) && !isRe) {//Gigabyte gb to terabytetb
sized=sized/1024;
}
size=(long) sized;
}
}else{//Big unit to small unit
if (FILE_UNIT_BIT.equals(new_unit) && FILE_UNIT_KB.equals(old_unit)) {//Kneimeter kb to bit bit
size=size*8*1024;
}else if (FILE_UNIT_BIT.equals(new_unit) && FILE_UNIT_MB.equals(old_unit)) {//Megabyte mb to bit bit
size=size*8*1024*1024;
}else if (FILE_UNIT_BIT.equals(new_unit) && FILE_UNIT_GB.equals(old_unit)) {//Gigabyte gb to bit bit
size=size*8*1024*1024*1024;
}else if (FILE_UNIT_BYTE.equals(new_unit) && FILE_UNIT_KB.equals(old_unit)) {//Kneimeter kb to byte byte
size=size*1024;
}else if (FILE_UNIT_BYTE.equals(new_unit) && FILE_UNIT_MB.equals(old_unit)) {//Megabyte mb to byte byte
size=size*1024*1024;
}else if (FILE_UNIT_BYTE.equals(new_unit) && FILE_UNIT_GB.equals(old_unit)) {//Gigabyte gb to byte byte
size=size*1024*1024*1024;
}else if (FILE_UNIT_KB.equals(new_unit) && FILE_UNIT_MB.equals(old_unit)) {//Megabyte mb to kilobyte kb
size=size*1024;
}else if (FILE_UNIT_KB.equals(new_unit) && FILE_UNIT_GB.equals(old_unit)) {//Gigabyte gb to kilobyte kb
size=size*1024*1024;
}else if (FILE_UNIT_MB.equals(new_unit) && FILE_UNIT_GB.equals(old_unit)) {//Gigabyte gb to megabyte mb
size=size*1024;
}else{//More type conversions
boolean isRe=false;
double sized=size;
if (FILE_UNIT_TB.equals(old_unit) && !isRe) {//Terabytet tb to gigabyte gb
sized=sized*1024;
old_unit=FILE_UNIT_GB;
}
isRe=(isRe || old_unit.equals(new_unit))?true:false;
if (FILE_UNIT_GB.equals(old_unit) && !isRe) {//Gigabyte gb to megabyte mb
sized=sized*1024;
old_unit=FILE_UNIT_MB;
}
isRe=(isRe || old_unit.equals(new_unit))?true:false;
if (FILE_UNIT_MB.equals(old_unit) && !isRe) {//Megabyte mb to kilobyte kb
sized=sized*1024;
old_unit=FILE_UNIT_KB;
}
isRe=(isRe || old_unit.equals(new_unit))?true:false;
if (FILE_UNIT_KB.equals(old_unit) && !isRe) {//Kneimeter kb to byte byte
sized=sized*1024;
old_unit=FILE_UNIT_BYTE;
}
isRe=(isRe || old_unit.equals(new_unit))?true:false;
if (FILE_UNIT_BYTE.equals(old_unit) && !isRe) {//Byte byte to bit bit
sized=sized*8;
}
size=(long) sized;
}
}
new_size=size;
}else{
throw new RuntimeException("No longer convert range, unit before conversion ["+old_unit+"], unit after conversion ["+new_unit+"]");
}
}else{
new_size=size;
("The same unit does not need to be converted, the unit before conversion ["+old_unit+"], and the unit after conversion ["+new_unit+"]");
}
}
return new_size;
}
/**
* Is the old unit smaller than the new unit
* @title
* @date January 7, 2019
* @author niuchang
* @param old_unit
* @param new_unit
* @return
*/
private static boolean isFileUnit(String old_unit,String new_unit){
if (old_unit.equals(FILE_UNIT_BIT) && !new_unit.equals(FILE_UNIT_BIT)) {
return true;
}else if (old_unit.equals(FILE_UNIT_BYTE) && (!new_unit.equals(FILE_UNIT_BIT) && !new_unit.equals(FILE_UNIT_BYTE))) {
return true;
}else if (old_unit.equals(FILE_UNIT_KB) && (!new_unit.equals(FILE_UNIT_BIT) && !new_unit.equals(FILE_UNIT_BYTE)
&& !new_unit.equals(FILE_UNIT_KB))) {
return true;
}else if (old_unit.equals(FILE_UNIT_MB) && (!new_unit.equals(FILE_UNIT_BIT) && !new_unit.equals(FILE_UNIT_BYTE)
&& !new_unit.equals(FILE_UNIT_KB) && !new_unit.equals(FILE_UNIT_MB))) {
return true;
}else if (old_unit.equals(FILE_UNIT_GB) && (!new_unit.equals(FILE_UNIT_BIT) && !new_unit.equals(FILE_UNIT_BYTE)
&& !new_unit.equals(FILE_UNIT_KB) && !new_unit.equals(FILE_UNIT_MB) && !new_unit.equals(FILE_UNIT_GB))) {
return true;
}else if (old_unit.equals(FILE_UNIT_TB) && (!new_unit.equals(FILE_UNIT_BIT) && !new_unit.equals(FILE_UNIT_BYTE)
&& !new_unit.equals(FILE_UNIT_KB) && !new_unit.equals(FILE_UNIT_MB) && !new_unit.equals(FILE_UNIT_GB)
&& !new_unit.equals(FILE_UNIT_TB))) {
throw new RuntimeException("The unit type conversion is not supported, the unit before conversion ["+old_unit+"], and the unit after conversion ["+new_unit+"]");
}else{
return false;
}
}