String to Hex to Byte Conversion in JAVA

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Hello All,

Thanks in advance.

I have one method setpower which is used to set hardware power.

Java

SetHardwarePower(new byte[]{0x0a,0x14,0x14,0x14});

In above method you 0x0a means in 10 , 0x14 means 20.

For API design I wrote one method For e.g. SetRfPower(10,20,20,20)

Java

public boolean SetPower(int Power1,int Power2,int Power3,int Power4)
{
    //here I have to convert int to hex
    String power1inhex = "0x";
    power1inhex += Integer.toHexString(Power1); // power1inhex = 0x0a
    
    // Please help me to write code here. How should I use power1inhex string as byte to pass in method SetHardwarePower.
    
    SetHardwarePower(new byte[]{0x0a,0x14,0x14,0x14});
}

I tried a lot. please let us know any separate approach.

Posted 5-Nov-15 22:51pm

Tejas Sawant 13

Updated 5-Nov-15 23:16pm

George Jonsson

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Richard MacCutchan 6-Nov-15 6:03am

There is nothing to convert: Hex 0x14 is exactly the same value as decimal 20.

[no name] 6-Nov-15 7:41am

but the value is in string format. Method needs it in byte format. If I write like

SetHardwarePower(new byte[]{power1inhex ,0x14,0x14,0x14});

it doesn't work.

Richard MacCutchan 6-Nov-15 10:06am

I suggest you buy a book on basic computer theory. You seem to have a total misunderstanding between the way data is stored, and how it is displayed.

Whether you write
SetHardwarePower(new byte[]{power1inhex ,0x14,0x14,0x14});
or

SetHardwarePower(new byte[]{power1inhex ,20,20,20});

the result is exactly the same.

[no name] 7-Nov-15 0:37am

Thanks for suggestion.
If it could be that much simple why should I asked here.

I tried that. But it doesn't work dear.

[no name] 7-Nov-15 0:38am

power1inhex is string it doesnt treat as byte

Richard MacCutchan 7-Nov-15 5:06am

Then you should have explained that in your question. And what exactly is contained in that string?

Richard MacCutchan 7-Nov-15 5:06am

That is why I suggest reading a book on the basics. Without a good understanding of the fundamentals you are always going to struggle.

[no name] 1-Jun-16 6:27am

well said

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George Jonsson · Accepted Answer · 2015-11-05T23:21:00

First of all, if you use int as your argument type you might run into an overflow situation. Better to use byte and do a type cast when you call the method (if necessary)

Java

public boolean SetPower(byte Power1, byte Power2, byte Power3, byte Power4)
{
    //here I have to convert int to hex
    String power1inhex = "0x";
    power1inhex += Integer.toHexString(Power1); // power1inhex = 0x0a

    // Please help me to write code here. How should I use power1inhex string as byte to pass in method SetHardwarePower.

    // No conversion needed. The computer will interpret your the input values as
    // hexadecimal numbers automatically. (Not the best explanation, I know) 
    SetHardwarePower(new byte[]{Power1, Power2, Power3, Power4});
}

If the user is entering decimal values as a string, you only need to convert from string to byte.

Java

string aString = "10";
byte aByte = (byte)Integer.parseInt(aString);
        dec   hex     binary
aByte = 10 or 0x0A or 0000 1010 (it all depends on how you choose to show the value)

Patrice T · Accepted Answer · 2015-11-06T10:28:00

The solution is to read Java documentation.

In Java documentation, you will learn that there is more than one way to write an integer in source code and the same apply to user integer input.

Any integer can be typed in Hexadecimal, Decimal, Octal and Binary. Your µ-proc only handle Binary, so the compiler and the integer input command silently convert any integer to its Binary representation, no matter what.
if the user input is 100 or 0144 or 0x64 or 0b1100100, you will only ever know the decimal value 100 stop
You don't have to care about theses details.
http://rodrigosasaki.com/2013/06/10/number-literals-in-java/[^]

String to Hex to Byte Conversion in JAVA

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