[Java]How to correct the overflowing variables generated from the situation we capture the single byte of data from files?

问题

As tilte,

I tried to capture the file size info which is saved in 4 bytes of data from bitmap's file code,

but if I use byte[] to save it and any byte of file exceeds 127, it'd be misjudged as negative values,

in this case how could we correct these kind of values?

My book just simply plus 256 to it, but could it fixedly be -128?

if not, then the result still isn't correct.

I know we can just use int[] or larger array for it, just wanna know how to deal with these kind of problems!

Thanks a lot for helping!!!

来源：https://stackoverflow.com/questions/31366865/javahow-to-correct-the-overflowing-variables-generated-from-the-situation-we-c