/** * Created by Administrator on 2017/12/2 0002. */import java.io.UnsupportedEncodingException;
public class Base64 { /** * Chunk size per RFC 2045 section 6.8. * <p/> * <p>The {@value} character limit does not count the trailing CRLF, but counts * all other characters, including any equal signs.</p> * * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a> */ static final int CHUNK_SIZE = 76;
/** * Chunk separator per RFC 2045 section 2.1. * * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a> */ static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes();
/** * The base length. */ static final int BASELENGTH = 255;
/** * Lookup length. */ static final int LOOKUPLENGTH = 64;
/** * Used to calculate the number of bits in a byte. */ static final int EIGHTBIT = 8;
/** * Used when encoding something which has fewer than 24 bits. */ static final int SIXTEENBIT = 16;
/** * Used to determine how many bits data contains. */ static final int TWENTYFOURBITGROUP = 24;
/** * Used to get the number of Quadruples. */ static final int FOURBYTE = 4;
/** * Used to test the sign of a byte. */ static final int SIGN = -128;
/** * Byte used to pad output. */ static final byte PAD = (byte) ‘=‘;
// Create arrays to hold the base64 characters and a // lookup for base64 chars private static byte[] base64Alphabet = new byte[BASELENGTH]; private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];
// Populating the lookup and character arrays static { for (int i = 0; i < BASELENGTH; i++) { base64Alphabet[i] = (byte) -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) ‘/‘; }
private static boolean isBase64(byte octect) { if (octect == PAD) { return true; } else if (base64Alphabet[octect] == -1) { return false; } else { return true; } }
/** * Tests a given byte array to see if it contains * only valid characters within the Base64 alphabet. * * @param arrayOctect byte array to test * @return true if all bytes are valid characters in the Base64 * alphabet or if the byte array is empty; false, otherwise */ public static boolean isArrayByteBase64(byte[] arrayOctect) {
arrayOctect = discardWhitespace(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; }
/** * Encodes binary data using the base64 algorithm but * does not chunk the output. * * @param binaryData binary data to encode * @return Base64 characters */ public static byte[] encodeBase64(byte[] binaryData) { return encodeBase64(binaryData, false); }
/** * Encodes binary data using the base64 algorithm and chunks * the encoded output into 76 character blocks * * @param binaryData binary data to encode * @return Base64 characters chunked in 76 character blocks */ public static byte[] encodeBase64Chunked(byte[] binaryData) { return encodeBase64(binaryData, true); }
/** * Decodes a byte[] containing containing * characters in the Base64 alphabet. * * @param pArray A byte array containing Base64 character data * @return a byte array containing binary data */ public static byte[] decode(byte[] pArray) { return decodeBase64(pArray); }
/** * Encodes binary data using the base64 algorithm, optionally * chunking the output into 76 character blocks. * * @param binaryData Array containing binary data to encode. * @param isChunked if isChunked is true this encoder will chunk * the base64 output into 76 character blocks * @return Base64-encoded data. */ public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) { int lengthDataBits = binaryData.length * EIGHTBIT; int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP; int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP; byte encodedData[] = null; int encodedDataLength = 0; int nbrChunks = 0;
if (fewerThan24bits != 0) { //data not divisible by 24 bit encodedDataLength = (numberTriplets + 1) * 4; } else { // 16 or 8 bit encodedDataLength = numberTriplets * 4; }
// If the output is to be "chunked" into 76 character sections, // for compliance with RFC 2045 MIME, then it is important to // allow for extra length to account for the separator(s) if (isChunked) {
nbrChunks = (CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math.ceil((float) encodedDataLength / CHUNK_SIZE)); encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length; }
encodedData = new byte[encodedDataLength];
byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;
int encodedIndex = 0; int dataIndex = 0; int i = 0; int nextSeparatorIndex = CHUNK_SIZE; int chunksSoFar = 0;
//log.debug("number of triplets = " + numberTriplets); for (i = 0; i < numberTriplets; i++) { dataIndex = i * 3; b1 = binaryData[dataIndex]; b2 = binaryData[dataIndex + 1]; b3 = binaryData[dataIndex + 2];
//log.debug("b1= " + b1 +", b2= " + b2 + ", b3= " + b3);
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]; //log.debug( "val2 = " + val2 ); //log.debug( "k4 = " + (k<<4) ); //log.debug( "vak = " + (val2 | (k<<4)) ); encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)]; encodedData[encodedIndex + 2] = lookUpBase64Alphabet[(l << 2) | val3]; encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];
encodedIndex += 4;
// If we are chunking, let‘s put a chunk separator down. if (isChunked) { // this assumes that CHUNK_SIZE % 4 == 0 if (encodedIndex == nextSeparatorIndex) { System.arraycopy( CHUNK_SEPARATOR, 0, encodedData, encodedIndex, CHUNK_SEPARATOR.length); chunksSoFar++; nextSeparatorIndex = (CHUNK_SIZE * (chunksSoFar + 1)) + (chunksSoFar * CHUNK_SEPARATOR.length); encodedIndex += CHUNK_SEPARATOR.length; } } }
// form integral number of 6-bit groups dataIndex = i * 3;
if (fewerThan24bits == EIGHTBIT) { b1 = binaryData[dataIndex]; k = (byte) (b1 & 0x03); //log.debug("b1=" + b1); //log.debug("b1<<2 = " + (b1>>2) ); 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; }
if (isChunked) { // we also add a separator to the end of the final chunk. if (chunksSoFar < nbrChunks) { System.arraycopy( CHUNK_SEPARATOR, 0, encodedData, encodedDataLength - CHUNK_SEPARATOR.length, CHUNK_SEPARATOR.length); } }
return encodedData; }
/** * Decodes Base64 data into octects * * @param base64Data Byte array containing Base64 data * @return Array containing decoded data. */ public static byte[] decodeBase64(byte[] base64Data) { // RFC 2045 requires that we discard ALL non-Base64 characters base64Data = discardNonBase64(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; }
/** * Discards any whitespace from a base-64 encoded block. * * @param data The base-64 encoded data to discard the whitespace * from. * @return The data, less whitespace (see RFC 2045). */ static byte[] discardWhitespace(byte[] data) { byte groomedData[] = new byte[data.length]; int bytesCopied = 0;
for (int i = 0; i < data.length; i++) { switch (data[i]) { case (byte) ‘ ‘: case (byte) ‘\n‘: case (byte) ‘\r‘: case (byte) ‘\t‘: break; default: groomedData[bytesCopied++] = data[i]; } }
byte packedData[] = new byte[bytesCopied];
System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
return packedData; }
/** * Discards any characters outside of the base64 alphabet, per * the requirements on page 25 of RFC 2045 - "Any characters * outside of the base64 alphabet are to be ignored in base64 * encoded data." * * @param data The base-64 encoded data to groom * @return The data, less non-base64 characters (see RFC 2045). */ static byte[] discardNonBase64(byte[] data) { byte groomedData[] = new byte[data.length]; int bytesCopied = 0;
for (int i = 0; i < data.length; i++) { if (isBase64(data[i])) { groomedData[bytesCopied++] = data[i]; } }
byte packedData[] = new byte[bytesCopied];
System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
return packedData; }
/** * Encodes a byte[] containing binary data, into a byte[] containing * characters in the Base64 alphabet. * * @param pArray a byte array containing binary data * @return A byte array containing only Base64 character data */ public static byte[] encode(byte[] pArray) { return encodeBase64(pArray, false); }
public static String encode(String str) throws UnsupportedEncodingException { String baseStr = new String(encode(str.getBytes("UTF-8"))); String tempStr = Digest.digest(str).toUpperCase(); String result = tempStr + baseStr; return new String(encode(result.getBytes("UTF-8"))); }
public static String decode(String cryptoStr) throws UnsupportedEncodingException { if (cryptoStr.length() < 40) return ""; try { String tempStr = new String(decode(cryptoStr.getBytes("UTF-8"))); String result = tempStr.substring(40, tempStr.length()); return new String(decode(result.getBytes("UTF-8"))); } catch (java.lang.ArrayIndexOutOfBoundsException ex) { return ""; } }
/** * Decodes Base64 data into octects * * @param encoded string containing Base64 data * @return Array containind decoded data. */ public static byte[] decode2(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; }
private static boolean isWhiteSpace(char octect) { return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9); }
private static boolean isData(char octect) { return (octect < BASELENGTH && base64Alphabet[octect] != -1); }
private static boolean isPad(char octect) { return (octect == PAD); }
/** * remove WhiteSpace from MIME containing encoded Base64 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; }}
原文地址：https://www.cnblogs.com/fgh2018/p/9408826.html
时间： 2024-10-14 06:09:23