Base16编码的Java语言实现如下：

private static final String base16EncodeTable = "0123456789ABCDEF";

public static String base16Encode(byte[] data) {
    if (data == null || data.length == 0) {
        return "";
    }
    StringBuilder result = new StringBuilder(data.length * 2);
    for (int i = 0; i < data.length; i++) {
        //向右移动4bit，获得高4bit
        int highByte = (data[i] >> 4) & 0x0F;
        //与0x0f做位与运算，获得低4bit
        int lowByte = data[i] & 0x0F;
        result.append(base16EncodeTable.charAt(highByte));
        result.append(base16EncodeTable.charAt(lowByte));
    }
    return result.toString();
}

Java语言中还可以使用如下简便方法实现Base16编码：

public static String base16Encode(byte[] data) {
    StringBuilder result = new StringBuilder(bytes.length * 2);
    for (byte b : bytes) { // 使用String的format方法进行转换
        result.append(String.format("%02X", new Integer(b & 0xFF)));
    }
    return result.toString();
}

Base16解码的Java语言实现如下：

//把16进制字符转换成10进制表示的数字
private static int hex2dec(char c) {
    if ('0' <= c && c <= '9') {
        return c - '0';
    } else if ('a' <= c && c <= 'f') {
        return c - 'a' + 10;
    } else if ('A' <= c && c <= 'F') {
        return c - 'A' + 10;
    } else {
        return 0;
    }
}

public static byte[] base16Decode(String input) {
    int inputLength = input.length();
    int halfInputLength = inputLength / 2;
    byte[] output = new byte[halfInputLength];
    for (int i = 0; i < halfInputLength; i++) {
        //16进制数字转换为10进制数字的过程
        output[i] = (byte) (hex2dec(input.charAt(2 * i)) * 16 + hex2dec(input.charAt(2 * i + 1)));
    }
    return output;
}