I have a byte array that's contains a string at the end of the array, and the beginning of the array is padded with zeroes. I'm using the following code to convert it to a string:
String myText = new String(byteArray, "UTF-8");
However, I'm getting a bunch of weird characters prepended to the string, due to the 0 padding. How do I get rid of it?
Use the String(byte[], int, int, String) constructor.
The first int is an offset through the byte[]: just look for the first non-zero byte; the second int is the number of bytes. So, call like:
new String(
byteArray, firstNonNullByte, byteArray.length - firstNonNullByte, "UTF-8");
No need to loop to find where the padding ends, you can fix the string using regex. Index juggling with loops is dangerous, because it would a perfect place to introduce by-one error one day.
String myText = (new String(byteArray, "UTF-8")).replaceAll("^\\x00*", "");
Regex means:
^)\x00, and \ should be escaped in java, so \\x00)*)My solution would be to remove zeros from the beginning of the array:
public byte[] trim(byte[] bytes) {
int i = 0;
while (i<bytes.length && bytes[i] == 0) {
i++;
}
return Arrays.copyOfRange(bytes, i, bytes.length);
}
You could use apache org.apache.commons.lang3.ArrayUtils.
int firstNonNullByte = ArrayUtils.lastIndexOf(byteArray, 0) + 1;
\0?
lastIndexOf. The question states "the beginning of the array is padded with zeroes", these are the ones you need to get rid of.I would try to remove the leading zeroes and then just use the remaining part of the byte array that is useful:
public class Test {
public static byte[] removeZeroes(byte[] data) {
int i;
for(i = 0; i < data.length; i++) {
if(data[i] != '\0') {
break;
}
}
return Arrays.copyOfRange(data, i, data.length);
}
public static void main(String args[]) {
byte[] byteArray = new byte[10];
byteArray[0] = '\0';
byteArray[1] = '\0';
byteArray[2] = '\0';
byteArray[3] = '\0';
byteArray[4] = 's';
byteArray[5] = 't';
byteArray[6] = 'r';
byteArray[7] = 'i';
byteArray[8] = 'n';
byteArray[9] = 'g';
byteArray = removeZeroes(byteArray);
try {
String myText = new String(byteArray, "UTF-8");
System.out.println(myText);
}
catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
byte array is padded with 0 rather than '0' (i.e. byte value of 48).