Base64 算法
<div style="border-right: #cccccc 1px solid; padding-right: 5px; border-top: #cccccc 1px solid; padding-left: 4px; font-size: 13px; padding-bottom: 4px; border-left: #cccccc 1px solid; width: 98%; padding-top: 4px; border-bottom: #cccccc 1px solid; background-color: #eeeeee;">http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedBlock.gifpublic class Base64 http://www.blogjava.net/Images/dot.gif{http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif private static final char[] S_BASE64CHAR = http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7',
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif '8', '9', '+', '/'
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif };
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif private static final char S_BASE64PAD = '=';
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif private static final byte[] S_DECODETABLE = new byte[128];
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif static http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif for (int i = 0; i < S_DECODETABLE.length; i ++)
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif S_DECODETABLE = Byte.MAX_VALUE; // 127
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif for (int i = 0; i < S_BASE64CHAR.length; i ++) // 0 to 63
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif S_DECODETABLE] = (byte)i;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif private static int decode0(char[] ibuf, byte[] obuf, int wp) http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int outlen = 3;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif if (ibuf[3] == S_BASE64PAD) outlen = 2;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif if (ibuf[2] == S_BASE64PAD) outlen = 1;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int b0 = S_DECODETABLE0]];
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int b1 = S_DECODETABLE1]];
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int b2 = S_DECODETABLE2]];
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int b3 = S_DECODETABLE3]];
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif switch (outlen) http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif case 1:
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif obuf = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return 1;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif case 2:
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif obuf++] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif obuf = (byte)(b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return 2;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif case 3:
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif obuf++] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif obuf++] = (byte)(b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif obuf = (byte)(b2 << 6 & 0xc0 | b3 & 0x3f);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return 3;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif default:
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif throw new RuntimeException("Internal Errror");
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif /** *//**
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * Decode the base64 data.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @param data The base64 encoded data to be decoded
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @param off The offset within the encoded data at which to start decoding
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @param len The length of data to decode
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @return The decoded data
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif public static byte[] decode(char[] data, int off, int len) http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif char[] ibuf = new char[4];
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int ibufcount = 0;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif byte[] obuf = new byte/4*3+3];
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int obufcount = 0;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif for (int i = off; i < off+len; i ++) http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif char ch = data;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif if (ch == S_BASE64PAD
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif || ch < S_DECODETABLE.length && S_DECODETABLE != Byte.MAX_VALUE) http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif ibuf++] = ch;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif if (ibufcount == ibuf.length) http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif ibufcount = 0;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif obufcount += decode0(ibuf, obuf, obufcount);
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif if (obufcount == obuf.length)
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return obuf;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif byte[] ret = new byte;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif System.arraycopy(obuf, 0, ret, 0, obufcount);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return ret;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif /** *//**
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * Decode the base64 data.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @param data The base64 encoded data to be decoded
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @return The decoded data
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif public static byte[] decode(String data) http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif char[] ibuf = new char[4];
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int ibufcount = 0;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif byte[] obuf = new byte/4*3+3];
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int obufcount = 0;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif for (int i = 0; i < data.length(); i ++) http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif char ch = data.charAt(i);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif if (ch == S_BASE64PAD
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif || ch < S_DECODETABLE.length && S_DECODETABLE != Byte.MAX_VALUE) http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif ibuf++] = ch;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif if (ibufcount == ibuf.length) http://www.blogjava.net/Images/dot.gif{
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif ibufcount = 0;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif obufcount += decode0(ibuf, obuf, obufcount);
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif if (obufcount == obuf.length)
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return obuf;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif byte[] ret = new byte;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif System.arraycopy(obuf, 0, ret, 0, obufcount);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return ret;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gifhttp://www.agoit.com/Images/OutliningIndicators/ContractedSubBlock.gif /** *//**
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * Decode the base64 data.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @param
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