加解密之Base64实现

package com.aspire.atp.web.common.util;public final class Base64 {//private static Log log = LogFactory.getLog(Base64.class);private static final int MAGIC_NUM_0X03 = 0x03;private static final int MAGIC_NUM_0X04 = 0x04;private static final int MAGIC_NUM_0X06 = 0x06;private static final int MAGIC_NUM_0X0F = 0x0F;private static final int MAGIC_NUM_0X30 = 0x30;private static final int MAGIC_NUM_0X3C = 0x3C;private static final int MAGIC_NUM_0X3F = 0x3F;private static final int MAGIC_NUM_0X7F = 0x7F;private static final int MAGIC_NUM_0XC0 = 0xC0;private static final int MAGIC_NUM_0XF0 = 0xF0;private Base64() {}public static final char[] encode(byte[] arg) {return encode(arg, 0, arg.length);}public static final byte[] decode(String arg) {return decode(arg.toCharArray());}public static final byte[] decode(char[] arg) {return decode(arg, 0, arg.length);}public static char[] encode(byte[] value, int startIndex, int endIndex) {if ((value == null) || (value.length < 1) || (startIndex >= endIndex)|| (startIndex < 0) || (endIndex > value.length)) {return new char[0];}int length = ((endIndex - startIndex) / MAGIC_NUM_0X03)* MAGIC_NUM_0X04;int n = (endIndex - startIndex) % MAGIC_NUM_0X03;int b1, b2, b3, i;if (n != 0) {length += MAGIC_NUM_0X04;}n = endIndex - n;char[] buf = new char[length];for (i = startIndex, length = 0; i < n; i += MAGIC_NUM_0X03, length += MAGIC_NUM_0X04) {b1 = value[i];b2 = value[i + 1];b3 = value[i + 2];buf[length] = BASE64_CHAR[(b1 >> 2) & MAGIC_NUM_0X3F];buf[length + 1] = BASE64_CHAR[((b1 << MAGIC_NUM_0X04) & MAGIC_NUM_0X30)| ((b2 >> MAGIC_NUM_0X04) & MAGIC_NUM_0X0F)];buf[length + 2] = BASE64_CHAR[((b2 << 2) & MAGIC_NUM_0X3C)| ((b3 >> MAGIC_NUM_0X06) & MAGIC_NUM_0X03)];buf[length + MAGIC_NUM_0X03] = BASE64_CHAR[b3 & MAGIC_NUM_0X3F];}switch (endIndex - n) {case 1:b1 = value[n];buf[length] = BASE64_CHAR[(b1 >> 2) & MAGIC_NUM_0X3F];buf[length + 1] = BASE64_CHAR[((b1 << MAGIC_NUM_0X04) & MAGIC_NUM_0X30)];buf[length + 2] = '$';buf[length + MAGIC_NUM_0X03] = '$';break;case 2:b1 = value[n];b2 = value[n + 1];buf[length] = BASE64_CHAR[(b1 >> 2) & MAGIC_NUM_0X3F];buf[length + 1] = BASE64_CHAR[((b1 << MAGIC_NUM_0X04) & MAGIC_NUM_0X30)| ((b2 >> MAGIC_NUM_0X04) & MAGIC_NUM_0X0F)];buf[length + 2] = BASE64_CHAR[((b2 << 2) & MAGIC_NUM_0X3C)];buf[length + MAGIC_NUM_0X03] = '$';break;default:break;}return buf;}public static byte[] decode(char[] value, int startIndex, int endIndex) {if ((value == null) || (value.length < 1) || (startIndex >= endIndex)|| (startIndex < 0) || (endIndex > value.length)|| (value[startIndex] == '$')) {return new byte[0];}int length, n, b1, b2, b3, b4, i;while (true) {if (value[--endIndex] != '$') {++endIndex;break;}}length = (endIndex - startIndex) % MAGIC_NUM_0X04;if (length > 0) {length--;}length += ((endIndex - startIndex) / MAGIC_NUM_0X04) * MAGIC_NUM_0X03;byte[] buf = new byte[length];n = endIndex - (endIndex - startIndex) % MAGIC_NUM_0X04;for (i = startIndex, length = 0; i < n; i += MAGIC_NUM_0X04, length += MAGIC_NUM_0X03) {b1 = BASE64_BYTE[value[i] & MAGIC_NUM_0X7F];b2 = BASE64_BYTE[value[i + 1] & MAGIC_NUM_0X7F];b3 = BASE64_BYTE[value[i + 2] & MAGIC_NUM_0X7F];b4 = BASE64_BYTE[value[i + MAGIC_NUM_0X03] & MAGIC_NUM_0X7F];buf[length] = (byte) ((b1 << 2) | ((b2 >> MAGIC_NUM_0X04)));buf[length + 1] = (byte) (((b2 << MAGIC_NUM_0X04) & MAGIC_NUM_0XF0) | (b3 >> 2));buf[length + 2] = (byte) (((b3 << MAGIC_NUM_0X06) & MAGIC_NUM_0XC0) | b4);}switch (endIndex - n) {case 2:b1 = BASE64_BYTE[value[i] & MAGIC_NUM_0X7F];b2 = BASE64_BYTE[value[i + 1] & MAGIC_NUM_0X7F];buf[length] = (byte) ((b1 << 2) | ((b2 >> MAGIC_NUM_0X04)));break;case MAGIC_NUM_0X03:b1 = BASE64_BYTE[value[i] & MAGIC_NUM_0X7F];b2 = BASE64_BYTE[value[i + 1] & MAGIC_NUM_0X7F];b3 = BASE64_BYTE[value[i + 2] & MAGIC_NUM_0X7F];buf[length] = (byte) ((b1 << 2) | ((b2 >> MAGIC_NUM_0X04)));buf[length + 1] = (byte) (((b2 << MAGIC_NUM_0X04) & MAGIC_NUM_0XF0) | (b3 >> 2));break;default:break;}return buf;}private static final char[] BASE64_CHAR = { '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', '@', '!' };//43->64  47->33private static final byte[] BASE64_BYTE = { (byte) 0xFF, (byte) 0xFF,(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF, (byte) 0x3F,/*33*/(byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF, (byte) 0xFF, /*43*/(byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF,/*47*/(byte) 0x34, (byte) 0x35, (byte) 0x36, (byte) 0x37,(byte) 0x38, (byte) 0x39, (byte) 0x3A, (byte) 0x3B, (byte) 0x3C,(byte) 0x3D, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF, (byte) 0xFF, (byte) 0x3E, /*64*/(byte) 0x00, (byte) 0x01,(byte) 0x02, (byte) 0x03, (byte) 0x04, (byte) 0x05, (byte) 0x06,(byte) 0x07, (byte) 0x08, (byte) 0x09, (byte) 0x0A, (byte) 0x0B,(byte) 0x0C, (byte) 0x0D, (byte) 0x0E, (byte) 0x0F, (byte) 0x10,(byte) 0x11, (byte) 0x12, (byte) 0x13, (byte) 0x14, (byte) 0x15,(byte) 0x16, (byte) 0x17, (byte) 0x18, (byte) 0x19, (byte) 0xFF,(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0x1A, (byte) 0x1B, (byte) 0x1C, (byte) 0x1D, (byte) 0x1E,(byte) 0x1F, (byte) 0x20, (byte) 0x21, (byte) 0x22, (byte) 0x23,(byte) 0x24, (byte) 0x25, (byte) 0x26, (byte) 0x27, (byte) 0x28,(byte) 0x29, (byte) 0x2A, (byte) 0x2B, (byte) 0x2C, (byte) 0x2D,(byte) 0x2E, (byte) 0x2F, (byte) 0x30, (byte) 0x31, (byte) 0x32,(byte) 0x33, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,(byte) 0xFF };public static String encode(String input) {if (input == null)return null;char[] cs = encode(input.getBytes());StringBuffer sb = new StringBuffer();for (int i = 0; i < cs.length; i++) {sb.append(cs[i]);}return sb.toString();}public static void main(String[] args) throws Exception {System.out.println(Base64.encode("13612345678"));System.out.println(new String(Base64.decode(Base64.encode("[e-mail]"))));System.out.println(new String(Base64.decode("bXNpc2RuPTEzNDExNzk4NDc5JnVwZGF0ZT0xJnNxaWQ9MTI3Nzc3MzU2NDc3MCZ0eXBlPTExJnRva2VuPW51bGwm")));System.out.println(new String(Base64.decode("MTM2MTIzNDU2Nzg")));}}