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

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

首先是网上大神给的类

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 isWhhttp://iteSpace(char octect) {

return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9);

}

private static boolean isPad(char octect) {

return (octect == PAD);

}

private staticCwTyc 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;

}

}

然后是我经过2次封装的类,注释很清楚,拿过去直接用就行

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);

}

}

以上所述是给大家介绍的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，希望对大家有所帮助，如果大家有任何疑问请给我留言，会及时回复大家的。在此也非常感谢大家对我们网站的支持！

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