在Java中将字节数组转换为字符串

Question

I try to convert byte array to string in java using new String( bytes, "UTF-8") method, but they only return the object. like this @AB4634bSbbfa

So, I searched some way to solve this problem.

I finally get valid string array, by converting hex-code to basic-character array. like this. char[] chars = {"0", "1", ... "e", "f"};

This never happened before why do i have to convert hex-code to get valid string.

Here is method. byte array which is hashed by Mac-sha-256 with specific key when i hashed.

    public static String getHashString() {
        String algorithm = "HmacSHA256";

        String hashKey = "some_key";
        String message = "abcdefg";

        String hexed = "";

        try {
            Mac sha256_HMAC = Mac.getInstance(algorithm);
            SecretKeySpec secret_key = new SecretKeySpec(hashKey.getBytes(), algorithm);
            sha256_HMAC.init(secret_key);

            byte[] hash = sha256_HMAC.doFinal(message.getBytes("UTF-8"));

            // it doesn't work for me.
//            hexed = new String(hash, "UTF-8");

            // it works.
            hexed = bytesToHex(hash);

        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        return hexed;
    }

    public static final char[] HEX_DIGITS = "0123456789abcdef".toCharArray();
    public static String bytesToHex(final byte[] data ) {
        final int l = data.length;
        final char[] hexChars = new char[l<<1];
        for( int i=0, j =0; i < l; i++ ) {
            hexChars[j++] = HEX_DIGITS[(0xF0 & data[i]) >>> 4];
            hexChars[j++] = HEX_DIGITS[0x0F & data[i]];
        }
        return new String(hexChars);
    }

Thanks.

Answer 1

Following is a sample which shows Conversion of Byte array to String :-

public class TestByte
{    
public static void main(String[] argv) {

        String example = "This is an example";
        byte[] bytes = example.getBytes();

        System.out.println("Text : " + example);
        System.out.println("Text [Byte Format] : " + bytes);
        System.out.println("Text [Byte Format] : " + bytes.toString());

        String s = new String(bytes);
        System.out.println("Text Decryted : " + s);
     }}

Answer 2

I'm not sure the string you get in the end is what you're after. I think a common scenario is to use

new BASE64Encoder().encode(hash)

which will return you the hashed message as String.

Answer 3

只是做新的String（byteArray）;