基于Java实现进制转换工具类的示例代码

/**
* 支持 import Java 标准库 (JDK 1.8)
*/
import java.util.*;

/**
* 六十二进制转换工具类
*/
public class Main {

  // 将字符集打乱就会带有一点加密效果
  private static final String chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

   private static final int scale = 62;

   public static void main(String []args) {
        Long source1 = 121231313213123L;
        String source2 = "IAvzjI19";
        System.out.println(source1 + " encode -> " + encode(source1, chars));
        System.out.println(source2 + " decode -> " + decode(source2, chars));
   }

   /**
     * 将数字转为62进制
     *
     * @param num Long 型数字
     * @return 62进制字符串
     */
    public static String encode(long num, String chars) {
        StringBuilder sb = new StringBuilder();
        int remainder;

        while (num > scale - 1) {
            remainder = Long.valueOf(num % scale).intValue();
            sb.append(chars.charAt(remainder));
            num = num / scale;
        }

        sb.append(chars.charAt(Long.valueOf(num).intValue()));
        return sb.reverse().toString();
    }

    /**
     * 62进制字符串转为数字
     *
     * @param str 编码后的62进制字符串
     * @return 解码后的 10 进制字符串
     */
    public static long decode(String str, String chars) {
        long num = 0;
        int index;
        for (int i = 0; i < str.length(); i++) {
            index = chars.indexOf(str.charAt(i));
            num += (long) (index * (Math.pow(scale, str.length() - i - 1)));
        }
        return num;
    }
}