Java Base64位编码与String字符串的相互转换,Base64与Bitmap的相互转换实例代码

package com.duanlian.daimengmusic.utils;public final class Base64Util {  private static final int BASELENGTH = 128;  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 FOURBYTE = 4;  private static final int SIGN = -128;  private static char PAD = '=';  private static byte[] base64Alphabet = new byte[BASELENGTH];  private static char[] lookUpBase64Alphabet = new char[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] = (char) ('A' + i);    }    for (int i = 26, j = 0; i <= 51; i++, j++) {      lookUpBase64Alphabet[i] = (char) ('a' + j);    }    for (int i = 52, j = 0; i <= 61; i++, j++) {      lookUpBase64Alphabet[i] = (char) ('0' + j);    }    lookUpBase64Alphabet[62] = (char) '+';    lookUpBase64Alphabet[63] = (char) '/';  }  private static boolean isWhiteSpace(char octect) {    return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9);  }  private static boolean isPad(char octect) {    return (octect == PAD);  }  private static boolean isData(char octect) {    return (octect < BASELENGTH && base64Alphabet[octect] != -1);  }  /**   把64位byte数组转换成String   */  public static String encode(byte[] binaryData) {    if (binaryData == null) {      return null;    }    int lengthDataBits = binaryData.length * EIGHTBIT;    if (lengthDataBits == 0) {      return "";    }    int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;    int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;    int numberQuartet = fewerThan24bits != 0 ? numberTriplets + 1        : numberTriplets;    char encodedData[] = null;    encodedData = new char[numberQuartet * 4];    byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;    int encodedIndex = 0;    int dataIndex = 0;    for (int i = 0; i < numberTriplets; i++) {      b1 = binaryData[dataIndex++];      b2 = binaryData[dataIndex++];      b3 = binaryData[dataIndex++];      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);      byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6)          : (byte) ((b3) >> 6 ^ 0xfc);      encodedData[encodedIndex++] = lookUpBase64Alphabet[val1];      encodedData[encodedIndex++] = lookUpBase64Alphabet[val2 | (k << 4)];      encodedData[encodedIndex++] = lookUpBase64Alphabet[(l << 2) | val3];      encodedData[encodedIndex++] = lookUpBase64Alphabet[b3 & 0x3f];    }    // form integral number of 6-bit groups    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++] = lookUpBase64Alphabet[k << 4];      encodedData[encodedIndex++] = PAD;      encodedData[encodedIndex++] = 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++] = lookUpBase64Alphabet[val2 | (k << 4)];      encodedData[encodedIndex++] = lookUpBase64Alphabet[l << 2];      encodedData[encodedIndex++] = PAD;    }    return new String(encodedData);  }  /**   * 把Base64位编码转换成byte数组   */  public static byte[] decode(String encoded) {    if (encoded == null) {      return null;    }    char[] base64Data = encoded.toCharArray();    // remove white spaces    int len = removeWhiteSpace(base64Data);    if (len % FOURBYTE != 0) {      return null;// should be divisible by four    }    int numberQuadruple = (len / FOURBYTE);    if (numberQuadruple == 0) {      return new byte[0];    }    byte decodedData[] = null;    byte b1 = 0, b2 = 0, b3 = 0, b4 = 0;    char d1 = 0, d2 = 0, d3 = 0, d4 = 0;    int i = 0;    int encodedIndex = 0;    int dataIndex = 0;    decodedData = new byte[(numberQuadruple) * 3];    for (; i < numberQuadruple - 1; i++) {      if (!isData((d1 = base64Data[dataIndex++]))          || !isData((d2 = base64Data[dataIndex++]))          || !isData((d3 = base64Data[dataIndex++]))          || !isData((d4 = base64Data[dataIndex++]))) {        return null;      }// if found "no data" just return null      b1 = base64Alphabet[d1];      b2 = base64Alphabet[d2];      b3 = base64Alphabet[d3];      b4 = base64Alphabet[d4];      decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);      decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));      decodedData[encodedIndex++] = (byte) (b3 << 6 | b4);    }    if (!isData((d1 = base64Data[dataIndex++]))        || !isData((d2 = base64Data[dataIndex++]))) {      return null;// if found "no data" just return null    }    b1 = base64Alphabet[d1];    b2 = base64Alphabet[d2];    d3 = base64Data[dataIndex++];    d4 = base64Data[dataIndex++];    if (!isData((d3)) || !isData((d4))) {// Check if they are PAD characters      if (isPad(d3) && isPad(d4)) {        if ((b2 & 0xf) != 0)// last 4 bits should be zero        {          return null;        }        byte[] tmp = new byte[i * 3 + 1];        System.arraycopy(decodedData, 0, tmp, 0, i * 3);        tmp[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);        return tmp;      } else if (!isPad(d3) && isPad(d4)) {        b3 = base64Alphabet[d3];        if ((b3 & 0x3) != 0)// last 2 bits should be zero        {          return null;        }        byte[] tmp = new byte[i * 3 + 2];        System.arraycopy(decodedData, 0, tmp, 0, i * 3);        tmp[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);        tmp[encodedIndex] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));        return tmp;      } else {        return null;      }    } else { // No PAD e.g 3cQl      b3 = base64Alphabet[d3];      b4 = base64Alphabet[d4];      decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);      decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));      decodedData[encodedIndex++] = (byte) (b3 << 6 | b4);    }    return decodedData;  }  /**   * remove WhiteSpace from MIME containing encoded Base64Util data.   *    * @param data   *      the byte array of base64 data (with WS)   * @return the new length   */  private static int removeWhiteSpace(char[] data) {    if (data == null) {      return 0;    }    // count characters that's not whitespace    int newSize = 0;    int len = data.length;    for (int i = 0; i < len; i++) {      if (!isWhiteSpace(data[i])) {        data[newSize++] = data[i];      }    }    return newSize;  }}

package com.duanlian.daimengmusic.utils;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.util.Base64;import java.io.ByteArrayOutputStream;import java.io.IOException;/** * 转换编码 */public class Base64Object {  /**   * 把base64的String码转换成正常显示的字符串   */  public static String base64ToString(String base64) {    byte[] decode = Base64Util.decode(base64);    String s = new String(decode);    return s;  }  /**   * 把String的转换成base64码   */  public static String stringToBase64(String ss) {    byte[] bytes = ss.getBytes();    String encode = Base64Util.encode(bytes);    return encode;  }  /**   * bitmap转为base64   * @param bitmap   * @return   */  public static String bitmapToBase641(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);  }}