base64和bitmap互相转换

 public class Base64 {
     /**
      * Default values for encoder/decoder flags.
      */
     public static final int DEFAULT = 0;

     /**
      * Encoder flag bit to omit the padding '=' characters at the end
      * of the output (if any).
      */
     public static final int NO_PADDING = 1;

     /**
      * Encoder flag bit to omit all line terminators (i.e., the output
      * will be on one long line).
      */
     public static final int NO_WRAP = 2;

     /**
      * Encoder flag bit to indicate lines should be terminated with a
      * CRLF pair instead of just an LF.  Has no effect if {@code
      * NO_WRAP} is specified as well.
      */
     public static final int CRLF = 4;

     /**
      * Encoder/decoder flag bit to indicate using the "URL and
      * filename safe" variant of Base64 (see RFC 3548 section 4) where
      * {@code -} and {@code _} are used in place of {@code +} and
      * {@code /}.
      */
     public static final int URL_SAFE = 8;

     /**
      * Flag to pass to {@link Base64OutputStream} to indicate that it
      * should not close the output stream it is wrapping when it
      * itself is closed.
      */
     public static final int NO_CLOSE = 16;

     //  --------------------------------------------------------
     //  shared code
     //  --------------------------------------------------------

     /* package */ static abstract class Coder {
         public byte[] output;
         public int op;

         /**
          * Encode/decode another block of input data.  this.output is
          * provided by the caller, and must be big enough to hold all
          * the coded data.  On exit, this.opwill be set to the length
          * of the coded data.
          *
          * @param finish true if this is the final call to process for
          *        this object.  Will finalize the coder state and
          *        include any final bytes in the output.
          *
          * @return true if the input so far is good; false if some
          *         error has been detected in the input stream..
          */
         public abstract boolean process(byte[] input, int offset, int len, boolean finish);

         /**
          * @return the maximum number of bytes a call to process()
          * could produce for the given number of input bytes.  This may
          * be an overestimate.
          */
         public abstract int maxOutputSize(int len);
     }

     //  --------------------------------------------------------
     //  decoding
     //  --------------------------------------------------------

     /**
      * Decode the Base64-encoded data in input and return the data in
      * a new byte array.
      *
      * <p>The padding '=' characters at the end are considered optional, but
      * if any are present, there must be the correct number of them.
      *
      * @param str    the input String to decode, which is converted to
      *               bytes using the default charset
      * @param flags  controls certain features of the decoded output.
      *               Pass {@code DEFAULT} to decode standard Base64.
      *
      * @throws IllegalArgumentException if the input contains
      * incorrect padding
      */
     public static byte[] decode(String str, int flags) {
         return decode(str.getBytes(), flags);
     }

     /**
      * Decode the Base64-encoded data in input and return the data in
      * a new byte array.
      *
      * <p>The padding '=' characters at the end are considered optional, but
      * if any are present, there must be the correct number of them.
      *
      * @param input the input array to decode
      * @param flags  controls certain features of the decoded output.
      *               Pass {@code DEFAULT} to decode standard Base64.
      *
      * @throws IllegalArgumentException if the input contains
      * incorrect padding
      */
     public static byte[] decode(byte[] input, int flags) {
         return decode(input, 0, input.length, flags);
     }

     /**
      * Decode the Base64-encoded data in input and return the data in
      * a new byte array.
      *
      * <p>The padding '=' characters at the end are considered optional, but
      * if any are present, there must be the correct number of them.
      *
      * @param input  the data to decode
      * @param offset the position within the input array at which to start
      * @param len    the number of bytes of input to decode
      * @param flags  controls certain features of the decoded output.
      *               Pass {@code DEFAULT} to decode standard Base64.
      *
      * @throws IllegalArgumentException if the input contains
      * incorrect padding
      */
     public static byte[] decode(byte[] input, int offset, int len, int flags) {
         // Allocate space for the most data the input could represent.
         // (It could contain less if it contains whitespace, etc.)
         Decoder decoder = new Decoder(flags, new byte[len*3/4]);

         if (!decoder.process(input, offset, len, true)) {
             throw new IllegalArgumentException("bad base-64");
         }

         // Maybe we got lucky and allocated exactly enough output space.
         if (decoder.op == decoder.output.length) {
             return decoder.output;
         }

         // Need to shorten the array, so allocate a new one of the
         // right size and copy.
         byte[] temp = new byte[decoder.op];
         System.arraycopy(decoder.output, 0, temp, 0, decoder.op);
         return temp;
     }

     /* package */ static class Decoder extends Coder {
         /**
          * Lookup table for turning bytes into their position in the
          * Base64 alphabet.
          */
         private static final int DECODE[] = {
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
             52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -1, -1,
             -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
             15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
             -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
             41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
         };

         /**
          * Decode lookup table for the "web safe" variant (RFC 3548
          * sec. 4) where - and _ replace + and /.
          */
         private static final int DECODE_WEBSAFE[] = {
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1,
             52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -1, -1,
             -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
             15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63,
             -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
             41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
             -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
         };

         /** Non-data values in the DECODE arrays. */
         private static final int SKIP = -1;
         private static final int EQUALS = -2;

         /**
          * States 0-3 are reading through the next input tuple.
          * State 4 is having read one '=' and expecting exactly
          * one more.
          * State 5 is expecting no more data or padding characters
          * in the input.
          * State 6 is the error state; an error has been detected
          * in the input and no future input can "fix" it.
          */
         private int state;   // state number (0 to 6)
         private int value;

         final private int[] alphabet;

         public Decoder(int flags, byte[] output) {
             this.output = output;

             alphabet = ((flags & URL_SAFE) == 0) ? DECODE : DECODE_WEBSAFE;
             state = 0;
             value = 0;
         }

         /**
          * @return an overestimate for the number of bytes {@code
          * len} bytes could decode to.
          */
         public int maxOutputSize(int len) {
             return len * 3/4 + 10;
         }

         /**
          * Decode another block of input data.
          *
          * @return true if the state machine is still healthy.  false if
          *         bad base-64 data has been detected in the input stream.
          */
         public boolean process(byte[] input, int offset, int len, boolean finish) {
             if (this.state == 6) return false;

             int p = offset;
             len += offset;

             // Using local variables makes the decoder about 12%
             // faster than if we manipulate the member variables in
             // the loop.  (Even alphabet makes a measurable
             // difference, which is somewhat surprising to me since
             // the member variable is final.)
             int state = this.state;
             int value = this.value;
             int op = 0;
             final byte[] output = this.output;
             final int[] alphabet = this.alphabet;

             while (p < len) {
                 // Try the fast path:  we're starting a new tuple and the
                 // next four bytes of the input stream are all data
                 // bytes.  This corresponds to going through states
                 // 0-1-2-3-0.  We expect to use this method for most of
                 // the data.
                 //
                 // If any of the next four bytes of input are non-data
                 // (whitespace, etc.), value will end up negative.  (All
                 // the non-data values in decode are small negative
                 // numbers, so shifting any of them up and or'ing them
                 // together will result in a value with its top bit set.)
                 //
                 // You can remove this whole block and the output should
                 // be the same, just slower.
                 if (state == 0) {
                     while (p+4 <= len &&
                            (value = ((alphabet[input[p] & 0xff] << 18) |
                                      (alphabet[input[p+1] & 0xff] << 12) |
                                      (alphabet[input[p+2] & 0xff] << 6) |
                                      (alphabet[input[p+3] & 0xff]))) >= 0) {
                         output[op+2] = (byte) value;
                         output[op+1] = (byte) (value >> 8);
                         output[op] = (byte) (value >> 16);
                         op += 3;
                         p += 4;
                     }
                     if (p >= len) break;
                 }

                 // The fast path isn't available -- either we've read a
                 // partial tuple, or the next four input bytes aren't all
                 // data, or whatever.  Fall back to the slower state
                 // machine implementation.

                 int d = alphabet[input[p++] & 0xff];

                 switch (state) {
                 case 0:
                     if (d >= 0) {
                         value = d;
                         ++state;
                     } else if (d != SKIP) {
                         this.state = 6;
                         return false;
                     }
                     break;

                 case 1:
                     if (d >= 0) {
                         value = (value << 6) | d;
                         ++state;
                     } else if (d != SKIP) {
                         this.state = 6;
                         return false;
                     }
                     break;

                 case 2:
                     if (d >= 0) {
                         value = (value << 6) | d;
                         ++state;
                     } else if (d == EQUALS) {
                         // Emit the last (partial) output tuple;
                         // expect exactly one more padding character.
                         output[op++] = (byte) (value >> 4);
                         state = 4;
                     } else if (d != SKIP) {
                         this.state = 6;
                         return false;
                     }
                     break;

                 case 3:
                     if (d >= 0) {
                         // Emit the output triple and return to state 0.
                         value = (value << 6) | d;
                         output[op+2] = (byte) value;
                         output[op+1] = (byte) (value >> 8);
                         output[op] = (byte) (value >> 16);
                         op += 3;
                         state = 0;
                     } else if (d == EQUALS) {
                         // Emit the last (partial) output tuple;
                         // expect no further data or padding characters.
                         output[op+1] = (byte) (value >> 2);
                         output[op] = (byte) (value >> 10);
                         op += 2;
                         state = 5;
                     } else if (d != SKIP) {
                         this.state = 6;
                         return false;
                     }
                     break;

                 case 4:
                     if (d == EQUALS) {
                         ++state;
                     } else if (d != SKIP) {
                         this.state = 6;
                         return false;
                     }
                     break;

                 case 5:
                     if (d != SKIP) {
                         this.state = 6;
                         return false;
                     }
                     break;
                 }
             }

             if (!finish) {
                 // We're out of input, but a future call could provide
                 // more.
                 this.state = state;
                 this.value = value;
                 this.op = op;
                 return true;
             }

             // Done reading input.  Now figure out where we are left in
             // the state machine and finish up.

             switch (state) {
             case 0:
                 // Output length is a multiple of three.  Fine.
                 break;
             case 1:
                 // Read one extra input byte, which isn't enough to
                 // make another output byte.  Illegal.
                 this.state = 6;
                 return false;
             case 2:
                 // Read two extra input bytes, enough to emit 1 more
                 // output byte.  Fine.
                 output[op++] = (byte) (value >> 4);
                 break;
             case 3:
                 // Read three extra input bytes, enough to emit 2 more
                 // output bytes.  Fine.
                 output[op++] = (byte) (value >> 10);
                 output[op++] = (byte) (value >> 2);
                 break;
             case 4:
                 // Read one padding '=' when we expected 2.  Illegal.
                 this.state = 6;
                 return false;
             case 5:
                 // Read all the padding '='s we expected and no more.
                 // Fine.
                 break;
             }

             this.state = state;
             this.op = op;
             return true;
         }
     }

     //  --------------------------------------------------------
     //  encoding
     //  --------------------------------------------------------

     /**
      * Base64-encode the given data and return a newly allocated
      * String with the result.
      *
      * @param input  the data to encode
      * @param flags  controls certain features of the encoded output.
      *               Passing {@code DEFAULT} results in output that
      *               adheres to RFC 2045.
      */
     public static String encodeToString(byte[] input, int flags) {
         try {
             return new String(encode(input, flags), "US-ASCII");
         } catch (UnsupportedEncodingException e) {
             // US-ASCII is guaranteed to be available.
             throw new AssertionError(e);
         }
     }

     /**
      * Base64-encode the given data and return a newly allocated
      * String with the result.
      *
      * @param input  the data to encode
      * @param offset the position within the input array at which to
      *               start
      * @param len    the number of bytes of input to encode
      * @param flags  controls certain features of the encoded output.
      *               Passing {@code DEFAULT} results in output that
      *               adheres to RFC 2045.
      */
     public static String encodeToString(byte[] input, int offset, int len, int flags) {
         try {
             return new String(encode(input, offset, len, flags), "US-ASCII");
         } catch (UnsupportedEncodingException e) {
             // US-ASCII is guaranteed to be available.
             throw new AssertionError(e);
         }
     }

     /**
      * Base64-encode the given data and return a newly allocated
      * byte[] with the result.
      *
      * @param input  the data to encode
      * @param flags  controls certain features of the encoded output.
      *               Passing {@code DEFAULT} results in output that
      *               adheres to RFC 2045.
      */
     public static byte[] encode(byte[] input, int flags) {
         return encode(input, 0, input.length, flags);
     }

     /**
      * Base64-encode the given data and return a newly allocated
      * byte[] with the result.
      *
      * @param input  the data to encode
      * @param offset the position within the input array at which to
      *               start
      * @param len    the number of bytes of input to encode
      * @param flags  controls certain features of the encoded output.
      *               Passing {@code DEFAULT} results in output that
      *               adheres to RFC 2045.
      */
     public static byte[] encode(byte[] input, int offset, int len, int flags) {
         Encoder encoder = new Encoder(flags, null);

         // Compute the exact length of the array we will produce.
         int output_len = len / 3 * 4;

         // Account for the tail of the data and the padding bytes, if any.
         if (encoder.do_padding) {
             if (len % 3 > 0) {
                 output_len += 4;
             }
         } else {
             switch (len % 3) {
                 case 0: break;
                 case 1: output_len += 2; break;
                 case 2: output_len += 3; break;
             }
         }

         // Account for the newlines, if any.
         if (encoder.do_newline && len > 0) {
             output_len += (((len-1) / (3 * Encoder.LINE_GROUPS)) + 1) *
                 (encoder.do_cr ? 2 : 1);
         }

         encoder.output = new byte[output_len];
         encoder.process(input, offset, len, true);

         assert encoder.op == output_len;

         return encoder.output;
     }

     /* package */ static class Encoder extends Coder {
         /**
          * Emit a new line every this many output tuples.  Corresponds to
          * a 76-character line length (the maximum allowable according to
          * <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>).
          */
         public static final int LINE_GROUPS = 19;

         /**
          * Lookup table for turning Base64 alphabet positions (6 bits)
          * into output bytes.
          */
         private static final byte ENCODE[] = {
             'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
             'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
             'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
             'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/',
         };

         /**
          * Lookup table for turning Base64 alphabet positions (6 bits)
          * into output bytes.
          */
         private static final byte ENCODE_WEBSAFE[] = {
             'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
             'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
             'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
             'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '_',
         };

         final private byte[] tail;
         /* package */ int tailLen;
         private int count;

         final public boolean do_padding;
         final public boolean do_newline;
         final public boolean do_cr;
         final private byte[] alphabet;

         public Encoder(int flags, byte[] output) {
             this.output = output;

             do_padding = (flags & NO_PADDING) == 0;
             do_newline = (flags & NO_WRAP) == 0;
             do_cr = (flags & CRLF) != 0;
             alphabet = ((flags & URL_SAFE) == 0) ? ENCODE : ENCODE_WEBSAFE;

             tail = new byte[2];
             tailLen = 0;

             count = do_newline ? LINE_GROUPS : -1;
         }

         /**
          * @return an overestimate for the number of bytes {@code
          * len} bytes could encode to.
          */
         public int maxOutputSize(int len) {
             return len * 8/5 + 10;
         }

         public boolean process(byte[] input, int offset, int len, boolean finish) {
             // Using local variables makes the encoder about 9% faster.
             final byte[] alphabet = this.alphabet;
             final byte[] output = this.output;
             int op = 0;
             int count = this.count;

             int p = offset;
             len += offset;
             int v = -1;

             // First we need to concatenate the tail of the previous call
             // with any input bytes available now and see if we can empty
             // the tail.

             switch (tailLen) {
                 case 0:
                     // There was no tail.
                     break;

                 case 1:
                     if (p+2 <= len) {
                         // A 1-byte tail with at least 2 bytes of
                         // input available now.
                         v = ((tail[0] & 0xff) << 16) |
                             ((input[p++] & 0xff) << 8) |
                             (input[p++] & 0xff);
                         tailLen = 0;
                     };
                     break;

                 case 2:
                     if (p+1 <= len) {
                         // A 2-byte tail with at least 1 byte of input.
                         v = ((tail[0] & 0xff) << 16) |
                             ((tail[1] & 0xff) << 8) |
                             (input[p++] & 0xff);
                         tailLen = 0;
                     }
                     break;
             }

             if (v != -1) {
                 output[op++] = alphabet[(v >> 18) & 0x3f];
                 output[op++] = alphabet[(v >> 12) & 0x3f];
                 output[op++] = alphabet[(v >> 6) & 0x3f];
                 output[op++] = alphabet[v & 0x3f];
                 if (--count == 0) {
                     if (do_cr) output[op++] = '\r';
                     output[op++] = '\n';
                     count = LINE_GROUPS;
                 }
             }

             // At this point either there is no tail, or there are fewer
             // than 3 bytes of input available.

             // The main loop, turning 3 input bytes into 4 output bytes on
             // each iteration.
             while (p+3 <= len) {
                 v = ((input[p] & 0xff) << 16) |
                     ((input[p+1] & 0xff) << 8) |
                     (input[p+2] & 0xff);
                 output[op] = alphabet[(v >> 18) & 0x3f];
                 output[op+1] = alphabet[(v >> 12) & 0x3f];
                 output[op+2] = alphabet[(v >> 6) & 0x3f];
                 output[op+3] = alphabet[v & 0x3f];
                 p += 3;
                 op += 4;
                 if (--count == 0) {
                     if (do_cr) output[op++] = '\r';
                     output[op++] = '\n';
                     count = LINE_GROUPS;
                 }
             }

             if (finish) {
                 // Finish up the tail of the input.  Note that we need to
                 // consume any bytes in tail before any bytes
                 // remaining in input; there should be at most two bytes
                 // total.

                 if (p-tailLen == len-1) {
                     int t = 0;
                     v = ((tailLen > 0 ? tail[t++] : input[p++]) & 0xff) << 4;
                     tailLen -= t;
                     output[op++] = alphabet[(v >> 6) & 0x3f];
                     output[op++] = alphabet[v & 0x3f];
                     if (do_padding) {
                         output[op++] = '=';
                         output[op++] = '=';
                     }
                     if (do_newline) {
                         if (do_cr) output[op++] = '\r';
                         output[op++] = '\n';
                     }
                 } else if (p-tailLen == len-2) {
                     int t = 0;
                     v = (((tailLen > 1 ? tail[t++] : input[p++]) & 0xff) << 10) |
                         (((tailLen > 0 ? tail[t++] : input[p++]) & 0xff) << 2);
                     tailLen -= t;
                     output[op++] = alphabet[(v >> 12) & 0x3f];
                     output[op++] = alphabet[(v >> 6) & 0x3f];
                     output[op++] = alphabet[v & 0x3f];
                     if (do_padding) {
                         output[op++] = '=';
                     }
                     if (do_newline) {
                         if (do_cr) output[op++] = '\r';
                         output[op++] = '\n';
                     }
                 } else if (do_newline && op > 0 && count != LINE_GROUPS) {
                     if (do_cr) output[op++] = '\r';
                     output[op++] = '\n';
                 }

                 assert tailLen == 0;
                 assert p == len;
             } else {
                 // Save the leftovers in tail to be consumed on the next
                 // call to encodeInternal.

                 if (p == len-1) {
                     tail[tailLen++] = input[p];
                 } else if (p == len-2) {
                     tail[tailLen++] = input[p];
                     tail[tailLen++] = input[p+1];
                 }
             }

             this.op = op;
             this.count = count;

             return true;
         }
     }

     private Base64() { }   // don't instantiate
 }

 /**
  * bitmap转为base64
  * @param bitmap
  * @return
  */
 public static String bitmapToBase64(Bitmap bitmap) {

     String result = null;
     ByteArrayOutputStream baos = null;
     try {
         if (bitmap != null) {
             baos = new ByteArrayOutputStream();
             bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);

             baos.flush();
             baos.close();

             byte[] bitmapBytes = baos.toByteArray();
             result = Base64.encodeToString(bitmapBytes, Base64.DEFAULT);
         }
     } catch (IOException e) {
         e.printStackTrace();
     } finally {
         try {
             if (baos != null) {
                 baos.flush();
                 baos.close();
             }
         } catch (IOException e) {
             e.printStackTrace();
         }
     }
     return result;
 }

 /**
  * base64转为bitmap
  * @param base64Data
  * @return
  */
 public static Bitmap base64ToBitmap(String base64Data) {
     byte[] bytes = Base64.decode(base64Data, Base64.DEFAULT);
     return BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
 }