java中实现 byte[]与16进制字符串相互转换

╰半橙微兮° 2022-04-11 14:54 198阅读 0赞

package string;
    import java.util.Arrays;
    
    /**
     * byte[]与16进制字符串相互转换
     */
    public class BytesHexStrTranslate {
    
        private static final char[] HEX_CHAR = {'0', '1', '2', '3', '4', '5',
                '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
    
        /**
         * 方法一：
         * 将byte[]转换为16进制字符串
         */
        public static String bytesToHexFun1(byte[] bytes) {
            // 一个byte为8位，可用两个十六进制位标识
            char[] buf = new char[bytes.length * 2];
            int a = 0;
            int index = 0;
            for(byte b : bytes) { // 使用除与取余进行转换
                if(b < 0) {
                    a = 256 + b;
                } else {
                    a = b;
                }
    
                buf[index++] = HEX_CHAR[a / 16];
                buf[index++] = HEX_CHAR[a % 16];
            }
    
            return new String(buf);
        }
    
        /**
         * 方法二：
         * 将byte[]转换为16进制字符串
         */
        public static String bytesToHexFun2(byte[] bytes) {
            char[] buf = new char[bytes.length * 2];
            int index = 0;
            for(byte b : bytes) { // 利用位运算进行转换，可以看作方法一的变种
                buf[index++] = HEX_CHAR[b >>> 4 & 0xf];
                buf[index++] = HEX_CHAR[b & 0xf];
            }
    
            return new String(buf);
        }
    
        /**
         * 方法三：
         * 将byte[]转换为16进制字符串
         *
         * @param bytes
         * @return
         */
        public static String bytesToHexFun3(byte[] bytes) {
            StringBuilder buf = new StringBuilder(bytes.length * 2);
            for(byte b : bytes) { // 使用String的format方法进行转换
                buf.append(String.format("%02x", new Integer(b & 0xff)));
            }
    
            return buf.toString();
        }
    
        /**
         * 将16进制字符串转换为byte[]
         *
         * @param str
         * @return
         */
        public static byte[] toBytes(String str) {
            if(str == null || str.trim().equals("")) {
                return new byte[0];
            }
    
            byte[] bytes = new byte[str.length() / 2];
            for(int i = 0; i < str.length() / 2; i++) {
                String subStr = str.substring(i * 2, i * 2 + 2);
                bytes[i] = (byte) Integer.parseInt(subStr, 16);
            }
    
            return bytes;
        }
    
        public static void main(String[] args) throws Exception {
            byte[] bytes = "hello world!".getBytes("utf-8");
            System.out.println("字节数组为：" + Arrays.toString(bytes));
            System.out.println("bytesToHexFun1：" + bytesToHexFun1(bytes));
            System.out.println("bytesToHexFun2：" + bytesToHexFun2(bytes));
            System.out.println("bytesToHexFun3：" + bytesToHexFun3(bytes));
    
            System.out.println("==================================");
    
            String str = "e6b58be8af95";
            System.out.println("转换后的字节数组：" + Arrays.toString(toBytes(str)));
            System.out.println(new String(toBytes(str), "utf-8"));
        }
    
    }

编译执行程序，结果如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3NzMyODI5_size_16_color_FFFFFF_t_70][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3NzMyODI5_size_16_color_FFFFFF_t_70]: /images/20220411/09a695d36c5042b2bad98409af8fbea5.png