package com.qianmi.weidian.common.util;import java.io.*;/** * This class provides encode/decode for RFC 2045 Base64 as defined by RFC 2045, * N. Freed and N. Borenstein. <a href="http://www.mamicode.com/http://www.ietf.org/rfc/rfc2045.txt">RFC * 2045</a>: <a href="http://www.mamicode.com/http://www.cn-java.com">????????</a>: *  * @author jackliu 2001.11 */public final class Base64Util{    private static final int BASELENGTH = 255;    private static final int LOOKUPLENGTH = 64;    private static final int TWENTYFOURBITGROUP = 24;    private static final int EIGHTBIT = 8;    private static final int SIXTEENBIT = 16;    // private static final int SIXBIT = 6;    private static final int FOURBYTE = 4;    // private static final int TWOBYTE = 2;    private static final int SIGN = -128;    private static final byte PAD = (byte) ‘=‘;    private static byte[] base64Alphabet = new byte[BASELENGTH];    private static 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 (!isBase64(arrayOctect[i]))            {                return false;            }        }        return true;    }    /**     * Encode String object;     *     * @param src String object to be encoded.     * @return encoded String;     */    public static String encodeString(String src)    {        return encode(src);    }    public static String encodeBytes(byte[] src)    {        if (src =http://www.mamicode.com/= null || src.length == 0) {            return null;        }        byte[] bytes = encode(src);        return new String(bytes);    }    /**     * Encode String object;     *     * @param src String object to be encoded.     * @return encoded String;     */    public static String encode(String src)    {        String target = null;        if (src != null)        {            byte[] bts1 = src.getBytes();            byte[] bts2 = encode(bts1);            if (bts2 != null)            {                target = new String(bts2);            }        }        return target;    }    /**     * 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 = http://www.mamicode.com/new byte[(numberTriplets + 1) * 4];        }        else        {            // 16 or 8 bit            encodedData = http://www.mamicode.com/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;    }    public static String decode(String src)    {        String target = null;        if (src != null)        {            byte[] bts1 = src.getBytes();            byte[] bts2 = decode(bts1);            if (bts2 != null)            {                target = new String(bts2);            }        }        return target;    }    public static String decode(String src, String charSet) throws UnsupportedEncodingException    {        String target = null;        if (src != null)        {            byte[] bts1 = src.getBytes();            byte[] bts2 = decode(bts1);            if (bts2 != null)            {                target = new String(bts2, charSet);            }        }        return target;    }    /**     * Decodes Base64 data into octects     *     * @param base64Data 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 null;        }        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 =http://www.mamicode.com/ base64Data.length;            // ignore the ‘=‘ padding            while (base64Data[lastData - 1] == PAD)            {                if (--lastData =http://www.mamicode.com/= 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;    }    /**     * 隐藏工具类的构造方法     */    protected Base64Util()    {        throw new UnsupportedOperationException();    }    /**     * 文件读取缓冲区大小     */    private static final int CACHE_SIZE = 1024;        /** *//**     * <p>     * BASE64字符串解码为二进制数据     * </p>     *     * @param base64     * @return     * @throws Exception     */    public static byte[] decodeString(String base64) throws Exception {        return Base64Util.decode(base64.getBytes());    }        /** *//**     * <p>     * 二进制数据编码为BASE64字符串     * </p>     *     * @param bytes     * @return     * @throws Exception     */    public static String encodeByte(byte[] bytes) throws Exception {        return new String(Base64Util.encode(bytes));    }        /** *//**     * <p>     * 将文件编码为BASE64字符串     * </p>     * <p>     * 大文件慎用，可能会导致内存溢出     * </p>     *     * @param filePath 文件绝对路径     * @return     * @throws Exception     */    public static String encodeFile(String filePath) throws Exception {        byte[] bytes = fileToByte(filePath);        return encodeByte(bytes);    }        /** *//**     * <p>     * BASE64字符串转回文件     * </p>     *     * @param filePath 文件绝对路径     * @param base64 编码字符串     * @throws Exception     */    public static void decodeToFile(String filePath, String base64) throws Exception {        byte[] bytes = decodeString(base64);        byteArrayToFile(bytes, filePath);    }        /** *//**     * <p>     * 文件转换为二进制数组     * </p>     *     * @param filePath 文件路径     * @return     * @throws Exception     */    public static byte[] fileToByte(String filePath) throws Exception {        byte[] data = http://www.mamicode.com/new byte[0];        File file = new File(filePath);        if (file.exists()) {            FileInputStream in = new FileInputStream(file);            ByteArrayOutputStream out = new ByteArrayOutputStream(2048);            byte[] cache = new byte[CACHE_SIZE];            int nRead = 0;            while ((nRead = in.read(cache)) != -1) {                out.write(cache, 0, nRead);                out.flush();            }            out.close();            in.close();            data = out.toByteArray();        }        return data;    }        /** *//**     * <p>     * 二进制数据写文件     * </p>     *     * @param bytes 二进制数据     * @param filePath 文件生成目录     */    public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {        InputStream in = new ByteArrayInputStream(bytes);        File destFile = new File(filePath);        if (!destFile.getParentFile().exists()) {            destFile.getParentFile().mkdirs();        }        destFile.createNewFile();        OutputStream out = new FileOutputStream(destFile);        byte[] cache = new byte[CACHE_SIZE];        int nRead = 0;        while ((nRead = in.read(cache)) != -1) {            out.write(cache, 0, nRead);            out.flush();        }        out.close();        in.close();    }}