如何在Java中将字节数组转换为String，并跳过所有空字节？

Question

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?

Thanks.

Answer 1

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");

Answer 2

您可以使用apache org.apache.commons.lang3.ArrayUtils。

int firstNonNullByte = ArrayUtils.lastIndexOf(byteArray, 0) + 1;

Answer 3

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();
    }

}

Answer 4

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);        
 }

Answer 5

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:

• at the beginning of string ( ^ )
• character with hexadecimal code 0 ( \\x00 , and \\ should be escaped in java, so \\\\x00 )
• zero or more times ( * )