通用工具类-Base64Encoder加密

public class Base64Encoder { private static final char last2byte = (char) Integer   .parseInt("00000011", 2); private static final char last4byte = (char) Integer   .parseInt("00001111", 2); private static final char last6byte = (char) Integer   .parseInt("00111111", 2); private static final char lead6byte = (char) Integer   .parseInt("11111100", 2); private static final char lead4byte = (char) Integer   .parseInt("11110000", 2); private static final char lead2byte = (char) Integer   .parseInt("11000000", 2); private static final char[] encodeTable = new 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', '+', '/' }; /**  * Base64 encoding.  * @param from The src data.  * @return  */ public static String encode(byte[] from) {  StringBuffer to = new StringBuffer((int) (from.length * 1.34) + 3);  int num = 0;  char currentByte = 0;  for (int i = 0; i < from.length; i++) {   num = num % 8;   while (num < 8) {    switch (num) {    case 0:     currentByte = (char) (from[i] & lead6byte);     currentByte = (char) (currentByte >>> 2);     break;    case 2:     currentByte = (char) (from[i] & last6byte);     break;    case 4:     currentByte = (char) (from[i] & last4byte);     currentByte = (char) (currentByte << 2);     if ((i + 1) < from.length) {      currentByte |= (from[i + 1] & lead2byte) >>> 6;     }     break;    case 6:     currentByte = (char) (from[i] & last2byte);     currentByte = (char) (currentByte << 4);     if ((i + 1) < from.length) {      currentByte |= (from[i + 1] & lead4byte) >>> 4;     }     break;    }    to.append(encodeTable[currentByte]);    num += 6;   }  }  if (to.length() % 4 != 0) {   for (int i = 4 - to.length() % 4; i > 0; i--) {    to.append("=");   }  }  return to.toString(); }}