base64工具类

其他 2019-02-19 14:24:45 阅读次数: 0

import java.net.URLDecoder;

import java.net.URLEncoder;

import sun.misc.BASE64Decoder;

import sun.misc.BASE64Encoder;

/**

 * ***********************************************************************

 * <br>description : base64工具类

************************************************************************

 */

public final class Base64 {

    static private final int BASELENGTH = 255;

    static private final int LOOKUPLENGTH = 64;

    static private final int TWENTYFOURBITGROUP = 24;

    static private final int EIGHTBIT = 8;

    static private final int SIXTEENBIT = 16;

    static private final int FOURBYTE = 4;

    static private final int SIGN = -128;

    static private final byte PAD = ( byte) '=';

    static private byte[] base64Alphabet = new byte[BASELENGTH];

    static private byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];

 

    static {

        for (int i = 0; i < BASELENGTH; i++) {

            base64Alphabet[i] = -1;

        }

        for (int i = 'Z'; i >= 'A'; i--) {

            base64Alphabet[i] = ( byte) (i - 'A');

        }

        for (int i = 'z'; i >= 'a'; i--) {

            base64Alphabet[i] = ( byte) (i - 'a' + 26);

        }

        for (int i = '9'; i >= '0'; i--) {

            base64Alphabet[i] = ( byte) (i - '0' + 52);

        }

 

        base64Alphabet['+'] = 62;

        base64Alphabet['/'] = 63;

 

        for (int i = 0; i <= 25; i++)

            lookUpBase64Alphabet[i] = ( byte) ('A' + i);

 

        for (int i = 26, j = 0; i <= 51; i++, j++)

            lookUpBase64Alphabet[i] = ( byte) ('a' + j);

 

        for (int i = 52, j = 0; i <= 61; i++, j++)

            lookUpBase64Alphabet[i] = ( byte) ('0' + j);

 

        lookUpBase64Alphabet[62] = ( byte) '+';

        lookUpBase64Alphabet[63] = ( byte) '/';

    }

 

    public static boolean isBase64(String isValidString) {

        return isArrayByteBase64(isValidString.getBytes());

    }

 

    public static boolean isBase64(byte octect) {

        //shall we ignore white space? JEFF??

        return (octect == PAD || base64Alphabet[octect] != -1);

    }

 

    public static boolean isArrayByteBase64(byte[] arrayOctect) {

        int length = arrayOctect.length;

        if (length == 0) {

            // shouldn't a 0 length array be valid base64 data?

            // return false;

            return true;

        }

        for (int i = 0; i < length; i++) {

            if (!Base64.isBase64(arrayOctect[i]))

                return false;

        }

        return true;

    }

 

    /**

     * Encodes hex octects into Base64.

     *

     * @param binaryData Array containing binary data to encode.

     * @return Base64-encoded data.

     */

    public static byte[] encode(byte[] binaryData) {

        int lengthDataBits = binaryData.length

            * EIGHTBIT;

        int fewerThan24bits = lengthDataBits

            % TWENTYFOURBITGROUP;

        int numberTriplets = lengthDataBits

            / TWENTYFOURBITGROUP;

        byte[] encodedData = null;

 

        if (fewerThan24bits != 0) {

            //data not divisible by 24 bit

            encodedData = new byte[(numberTriplets + 1) * 4];

        } else {

            // 16 or 8 bit

            encodedData = new byte[numberTriplets * 4];

        }

 

        byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;

 

        int encodedIndex = 0;

        int dataIndex = 0;

        int i = 0;

        for (i = 0; i < numberTriplets; i++) {

            dataIndex = i * 3;

            b1 = binaryData[dataIndex];

            b2 = binaryData[dataIndex + 1];

            b3 = binaryData[dataIndex + 2];

 

            l = ( byte) (b2 & 0x0f);

            k = ( byte) (b1 & 0x03);

 

            encodedIndex = i * 4;

            byte val1 = ((b1 & SIGN) == 0) ? ( byte) (b1 >> 2)

                    : ( byte) ((b1) >> 2 ^ 0xc0);

            byte val2 = ((b2 & SIGN) == 0) ? ( byte) (b2 >> 4)

                    : ( byte) ((b2) >> 4 ^ 0xf0);

            byte val3 = ((b3 & SIGN) == 0) ? ( byte) (b3 >> 6)

                    : ( byte) ((b3) >> 6 ^ 0xfc);

 

            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];

            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2

                | (k << 4)];

            encodedData[encodedIndex + 2] = lookUpBase64Alphabet[(l << 2)

                | val3];

            encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];

        }

 

        // form integral number of 6-bit groups

        dataIndex = i * 3;

        encodedIndex = i * 4;

        if (fewerThan24bits == EIGHTBIT) {

            b1 = binaryData[dataIndex];

            k = ( byte) (b1 & 0x03);

            byte val1 = ((b1 & SIGN) == 0) ? ( byte) (b1 >> 2)

                    : ( byte) ((b1) >> 2 ^ 0xc0);

            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];

            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];

            encodedData[encodedIndex + 2] = PAD;

            encodedData[encodedIndex + 3] = PAD;

        } else if (fewerThan24bits == SIXTEENBIT) {

 

            b1 = binaryData[dataIndex];

            b2 = binaryData[dataIndex + 1];

            l = ( byte) (b2 & 0x0f);

            k = ( byte) (b1 & 0x03);

 

            byte val1 = ((b1 & SIGN) == 0) ? ( byte) (b1 >> 2)

                    : ( byte) ((b1) >> 2 ^ 0xc0);

            byte val2 = ((b2 & SIGN) == 0) ? ( byte) (b2 >> 4)

                    : ( byte) ((b2) >> 4 ^ 0xf0);

 

            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];

            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2

                | (k << 4)];

            encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];

            encodedData[encodedIndex + 3] = PAD;

        }

 

        return encodedData;

    }

 

    /**

     * Decodes Base64 data into octects

     *

     * @param binaryData Byte array containing Base64 data

     * @return Array containing decoded data.

     */

    public static byte[] decode(byte[] base64Data) {

        // handle the edge case, so we don't have to worry about it later

        if (base64Data.length == 0) {

            return new byte[0];

        }

 

        int numberQuadruple = base64Data.length

            / FOURBYTE;

        byte[] decodedData = null;

        byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;

 

        // Throw away anything not in base64Data

 

        int encodedIndex = 0;

        int dataIndex = 0;

        {

            // this sizes the output array properly - rlw

            int lastData = base64Data.length;

            // ignore the '=' padding

            while (base64Data[lastData - 1] == PAD) {

                if (--lastData == 0) {

                    return new byte[0];

                }

            }

            decodedData = new byte[lastData

                - numberQuadruple];

        }

 

        for (int i = 0; i < numberQuadruple; i++) {

            dataIndex = i * 4;

            marker0 = base64Data[dataIndex + 2];

            marker1 = base64Data[dataIndex + 3];

 

            b1 = base64Alphabet[base64Data[dataIndex]];

            b2 = base64Alphabet[base64Data[dataIndex + 1]];

 

            if (marker0 != PAD

                && marker1 != PAD) {

                //No PAD e.g 3cQl

                b3 = base64Alphabet[marker0];

                b4 = base64Alphabet[marker1];

 

                decodedData[encodedIndex] = ( byte) (b1 << 2 | b2 >> 4);

                decodedData[encodedIndex + 1] = ( byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));

                decodedData[encodedIndex + 2] = ( byte) (b3 << 6 | b4);

            } else if (marker0 == PAD) {

                //Two PAD e.g. 3c[Pad][Pad]

                decodedData[encodedIndex] = ( byte) (b1 << 2 | b2 >> 4);

            } else if (marker1 == PAD) {

                //One PAD e.g. 3cQ[Pad]

                b3 = base64Alphabet[marker0];

 

                decodedData[encodedIndex] = ( byte) (b1 << 2 | b2 >> 4);

                decodedData[encodedIndex + 1] = ( byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));

            }

            encodedIndex += 3;

        }

        return decodedData;

    }

 

   /**BASE64编码，去除BASE64后多余的“\n”,再URLEncode

    * @param src

    * @return

    * @throws Exception

    */

   public static String doBase64URLEncode(String src)

      throws ParameterCheckException {

        try{

           byte[] raw = src.getBytes();

           BASE64Encoder encoder = new BASE64Encoder();

           String base64data = encoder.encode(raw);

           base64data = filter(base64data);

           base64data = doURLEncode(base64data);

           return base64data;

        }catch(Exception e){

           throw new ParameterCheckException("src进行Base64解码失败");

        }

     

 

   }

   /**BASE64编码，去除BASE64后多余的“\n”,再URLEncode（指定编码字符集）

    * @param src

    * @param enc

    * @return

    * @throws Exception

    */

   public static String doBase64URLEncode(String src,String enc)

   throws Exception {

     

      byte[] raw = src.getBytes();

      BASE64Encoder encoder = new BASE64Encoder();

      String base64data = encoder.encode(raw);

      base64data = filter(base64data);

      base64data = doURLEncode(base64data,enc);

      return base64data;

 

   }

  

   /**BASE64解码，URLDecode后BASE64Decoder解码

    * @param src

    * @return

    * @throws Exception

    */

   public static String doBase64URLDecode(String src)

   throws ParameterCheckException {

      try{

        src = doURLDecode(src);

        BASE64Decoder decoder = new BASE64Decoder();

        byte[] raw = decoder.decodeBuffer(src);

        return new String(raw);

      }catch(Exception e){

        throw new ParameterCheckException("src进行Base64解码失败");

      }

   }

   /**BASE64解码，URLDecode后BASE64Decoder解码（指定编码字符集）

    * @param src

    * @param enc

    * @return

    * @throws Exception

    */

   public static String doBase64URLDecode(String src,String enc)

   throws Exception {

      src = doURLDecode(src,enc);

      BASE64Decoder decoder = new BASE64Decoder();

      byte[] raw = decoder.decodeBuffer(src);

      return new String(raw);

 

   }

  

   /**

    * 去掉字符串的换行符号

    * base64编码3-DES的数据时，得到的字符串有换行符号

    *

    */

    private static String filter(String str) {

        String output = null;

        StringBuffer sb = new StringBuffer();

        for(int i = 0; i < str.length(); i++)

        {

        int asc = str.charAt(i);

        if(asc != 10 && asc != 13)

        sb.append(str.subSequence(i, i + 1));

        }

        output = new String(sb);

        return output;

    }

    /**

     * 对字符串进行URLDecoder.encode(src)编码

     * @param String src 要进行编码的字符串

     * @return  String 进行编码后的字符串

     */

    

    private static String doURLEncode(String src) {

        String result = "";

        try{

          result = URLEncoder.encode(src);

        }

        catch(Exception e){

          e.printStackTrace();

        }

        return result;

    }

    /**

     * 对字符串进行URLDecoder.encode(src)编码

     * @param String src 要进行编码的字符串

     * @param String enc 编码字符集

     * @return  String 进行编码后的字符串

    */

   private static String doURLEncode(String src,String enc) {

        String result = "";

        try{

          result = URLEncoder.encode(src,enc);

        }

        catch(Exception e){

          e.printStackTrace();

        }

        return result;

    }

    /**

     * 对字符串进行URLDecoder.decode(src)解码

     * @param String src 要进行解码的字符串

     * @return  String 进行解码后的字符串

     */

    

    private static String doURLDecode(String src)

    {  

        String result="";

        try{

          result = URLDecoder.decode(src);

        }

        catch(Exception e){

          e.printStackTrace();

        }

        return result;

    }

    /**

     * 对字符串进行URLDecoder.decode解码

     * @param String src 要进行解码的字符串

     * @param String enc 编码字符集

     * @return  String 进行解码后的字符串

    */

   private static String doURLDecode(String src,String enc)

    {  

        String result="";

        try{

          result = URLDecoder.decode(src,enc);

        }

        catch(Exception e){

          e.printStackTrace();

        }

        return result;

    }

   

}

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