java操作16进制的各种方法

 File file = new File("");
        FileInputStream fis = new FileInputStream(file);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        int len = -1;
        byte[] buf = new byte[1024];
        while((len = fis.read(buf)) != -1) {//汇总字节流到内存
            baos.write(buf, 0, len);
        }
        baos.close();
        fis.close();
        byte[] bytes = baos.toByteArray();
        String result=HexDump.toHexString(bytes);
        firmwareMapper.insertContent(result);

public class HexDump {
    private final static char[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};//十六进制的组成元素

    /**
     * 字节数组以String形式输出 以空格分隔,如：FE 00 12 0F 0E
     *
     * @param array 字节数组
     * @return
     */
    public static String dumpHexString(byte[] array) {
        return dumpHexString(array, 0, array.length);
    }

    /**
     * 字节数组以String形式输出 字节间以空格分隔
     *
     * @param array  字节数组
     * @param offset 起始位置
     * @param length 长度
     * @return
     */
    public static String dumpHexString(byte[] array, int offset, int length) {
        StringBuilder result = new StringBuilder();

        byte[] line = new byte[16];
        int lineIndex = 0;

        result.append("\n0x");
        result.append(toHexString(offset));

        for (int i = offset; i < offset + length; i++) {
            if (lineIndex == 16) {
                result.append(" ");

                for (int j = 0; j < 16; j++) {
                    if (line[j] > ' ' && line[j] < '~') {
                        result.append(new String(line, j, 1));
                    } else {
                        result.append(".");
                    }
                }

                result.append("\n0x");
                result.append(toHexString(i));
                lineIndex = 0;
            }

            byte b = array[i];
            result.append(" ");
            result.append(HEX_DIGITS[(b >>> 4) & 0x0F]);
            result.append(HEX_DIGITS[b & 0x0F]);

            line[lineIndex++] = b;
        }

        if (lineIndex != 16) {
            int count = (16 - lineIndex) * 3;
            count++;
            for (int i = 0; i < count; i++) {
                result.append(" ");
            }

            for (int i = 0; i < lineIndex; i++) {
                if (line[i] > ' ' && line[i] < '~') {
                    result.append(new String(line, i, 1));
                } else {
                    result.append(".");
                }
            }
        }

        return result.toString();
    }

    /**
     * 字节转16进制String
     *
     * @param b 字节
     * @return
     */
    public static String toHexString(byte b) {
        return toHexString(toByteArray(b));
    }

    /**
     * 字节数组转16进制String，无分隔，如：FE00120F0E
     *
     * @param array 字节数组
     * @return
     */
    public static String toHexString(byte[] array) {
        return toHexString(array, 0, array.length);
    }

    /**
     * 字节数组转16进制String，无分隔，如：FE00120F0E
     *
     * @param array  字节数组
     * @param offset 起始
     * @param length 长度
     * @return
     */
    public static String toHexString(byte[] array, int offset, int length) {
        char[] buf = new char[length * 2];

        int bufIndex = 0;
        for (int i = offset; i < offset + length; i++) {
            byte b = array[i];
            buf[bufIndex++] = HEX_DIGITS[(b >>> 4) & 0x0F];
            buf[bufIndex++] = HEX_DIGITS[b & 0x0F];
        }

        return new String(buf);
    }

    /**
     * int转16进制String
     *
     * @param i
     * @return
     */
    public static String toHexString(int i) {
        return toHexString(toByteArray(i));
    }

    /**
     * 字节转数组
     *
     * @param b
     * @return
     */
    public static byte[] toByteArray(byte b) {
        byte[] array = new byte[1];
        array[0] = b;
        return array;
    }

    /**
     * int转字节数组
     *
     * @param i
     * @return
     */
    public static byte[] toByteArray(int i) {
        byte[] array = new byte[4];

        array[3] = (byte) (i & 0xFF);
        array[2] = (byte) ((i >> 8) & 0xFF);
        array[1] = (byte) ((i >> 16) & 0xFF);
        array[0] = (byte) ((i >> 24) & 0xFF);

        return array;
    }

    /**
     * 十六进制转int
     *
     * @param c
     * @return
     */
    private static int toByte(char c) {
        if (c >= '0' && c <= '9') return (c - '0');
        if (c >= 'A' && c <= 'F') return (c - 'A' + 10);
        if (c >= 'a' && c <= 'f') return (c - 'a' + 10);

        throw new RuntimeException("Invalid hex char '" + c + "'");
    }

    /**
     * 十六进制字符串转字节数组
     *
     * @param hexString 如：FE00120F0E
     * @return
     */
    public static byte[] hexStringToByteArray(String hexString) {
        int length = hexString.length();
        byte[] buffer = new byte[length / 2];

        for (int i = 0; i < length; i += 2) {
            buffer[i / 2] = (byte) ((toByte(hexString.charAt(i)) << 4) | toByte(hexString.charAt(i + 1)));
        }

        return buffer;
    }
}