Possible Duplicate:
How do I reverse an int array in Java?
What is the equivalent function in java to perform Array.Reverse(bytearray) in C# ?
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1stackoverflow.com/questions/2137755/…Alex– Alex2012-10-15 10:33:36 +00:00Commented Oct 15, 2012 at 10:33
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Do you want to do that in Java or C#?Rohit Jain– Rohit Jain2012-10-15 10:36:33 +00:00Commented Oct 15, 2012 at 10:36
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java2s.com/Code/Java/Collections-Data-Structure/…maxstreifeneder– maxstreifeneder2012-10-15 10:37:32 +00:00Commented Oct 15, 2012 at 10:37
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Can you say why you need to do this because if you want to switch between little endian and big endian there are much better ways of doing this?Peter Lawrey– Peter Lawrey2012-10-15 10:51:13 +00:00Commented Oct 15, 2012 at 10:51
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Actually, we are trying to decrypt the .net encrypted string(RSA).In that, we faced some padding issue.To resolve, we wanted to reverse the byte array.For more information click heresat– sat2012-10-15 11:38:46 +00:00Commented Oct 15, 2012 at 11:38
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3 Answers
public static void reverse(byte[] array) {
if (array == null) {
return;
}
int i = 0;
int j = array.length - 1;
byte tmp;
while (j > i) {
tmp = array[j];
array[j] = array[i];
array[i] = tmp;
j--;
i++;
}
}
Comments
You can use Collections.reverse on a list returned by Arrays.asList operated on an Array: -
Byte[] byteArr = new Byte[5];
byteArr[0] = 123; byteArr[1] = 45;
byteArr[2] = 56; byteArr[3] = 67;
byteArr[4] = 89;
List<Byte> byteList = Arrays.asList(byteArr);
Collections.reverse(byteList); // Reversing list will also reverse the array
System.out.println(byteList);
System.out.println(Arrays.toString(byteArr));
OUTPUT: -
[89, 67, 56, 45, 123]
[89, 67, 56, 45, 123]
UPDATE: -
Or, you can also use: Apache Commons ArrayUtils#reverse method, that directly operate on primitive type array: -
byte[] byteArr = new byte[5];
ArrayUtils.reverse(byteArr);
3 Comments
Rohit Jain
@MarkoTopolnik Didn't knew that. At first I thought you meant something else. Thanks. Edited. :)
Marko Topolnik
And as a convenience, it is most practical to print an array's contents using
Arrays.toString(array).Rohit Jain
@MarkoTopolnik Okay. I always used array.toString() and got wierd
HashCodes.. :( Thanks a million for that..You may use java.util.Collections.reverse(). It takes java.util.List as an input argument. So you should convert your byteArray into a List either by doing Arrays.asList(byteArray) or by creating an List object and adding byte values into it.
