62进制

部分代码来源开源网友，笔记，侵删

//字符顺序可以乱的，但是由于三位0补全的关系，第一个index必须是'0',
	private static char[]cs = new char[]{'0','1','2','3','4','5','6','7','8','9','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'};

	private static String to62(long num10) {
		Stack<Character> stack = new Stack<Character>();
		StringBuffer r = new StringBuffer(0);
		if (num10!=0) {
			long quotient = num10;
			while (quotient!=0) {
				long mod = quotient%62;
				int index = new Long(mod).intValue();
				char c = cs[index];
				stack.add(c);
				quotient=quotient/62;
			}
		}else {
			stack.add(cs[0]);
		}
		while (!stack.isEmpty()) {
			r.append(stack.pop());
		}
		return r.toString();
		

	}

	private static int get10(char c) {
		for (int i = 0; i < cs.length; i++) {
			if (c == cs[i]) {
				return i;
			}
		}
		return -1;
	}

	private static long to10(String num62) {
		char[] arr = num62.toCharArray();
		int len = arr.length;
		long sum = 0;
		for (int i = 0; i < len; i++) {
			int a = get10(arr[i]);
			if (a == -1) {
				return -1;
			}
			double b = Math.pow(62, len - 1 - i);
			long c = new Double(b).longValue();
			sum += c * a;
		}
		return sum;
	}
	private static String fillZero(String s){
		int size = s.length();
		int dis = 3-size;
		for (int i = 0; i < dis; i++) {
			s="0"+s;
		}
		return s;
	}
	private static String removeZero(String s){
		char[]cs = s.toCharArray();
		StringBuffer r = new StringBuffer(0);
		boolean bool = true;//是0
		for (char c : cs) {
			if (bool) {
				if (c=='0') {
					continue;
				}else {
					r.append(c);
					bool=false;
				}
			}else {
				r.append(c);
			}
		}
		String u = r.toString();
		if (u.equals("")) {
			u="0";
		}
		return u;
	}
	/**
	 * 加密
	 * @param text
	 * @return
	 */
	public static String enc(String text){
		StringBuffer sb  = new StringBuffer(0);
		char[]cs = text.toCharArray();
		for (char c : cs) {
			int b = (int)c;
			String d = to62(b);
			String a = fillZero(d);
			sb.append(a);
		}
		return sb.toString();
	}
	/**
	 * 解密
	 * @param text
	 * @return
	 */
	public static String dec(String text){
		char[]arr = text.toCharArray();
		StringBuffer r = new StringBuffer(0);
		StringBuffer temp = new StringBuffer(0);
		for (int i = 0; i < arr.length; i++) {
			
			if ((i+1)%3==0) {
				temp.append(arr[i]);
				String a = temp.toString();
				char cc = (char)to10(removeZero(a));
				r.append(cc);
				temp.setLength(0);
			}else {
				temp.append(arr[i]);
			}
		}
		return r.toString();
		
	}