两种方法实现10进制和62进制互转

来源：互联网发布：java常用算法手册宋娟编辑：程序博客网时间：2024/05/18 11:48
import java.util.Stack;      public class Test {  private static char[] charSet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".toCharArray();              /**      * 将10进制转化为62进制       * @param number       * @param length 转化成的62进制长度，不足length长度的话高位补0，否则不改变什么      * @return      */      public static String _10_to_62(long number, int length){           Long rest=number;           Stack<Character> stack=new Stack<Character>();           StringBuilder result=new StringBuilder(0);           while(rest!=0){               stack.add(charSet[new Long((rest-(rest/62)*62)).intValue()]);               rest=rest/62;           }           for(;!stack.isEmpty();){               result.append(stack.pop());           }           int result_length = result.length();           StringBuilder temp0 = new StringBuilder();           for(int i = 0; i < length - result_length; i++){               temp0.append('0');           }                      return temp0.toString() + result.toString();        }                  /**      * 将62进制转换成10进制数      *       * @param ident62      * @return      */      private static String convertBase62ToDecimal( String ident62 ) {          int decimal = 0;          int base = 62;          int keisu = 0;          int cnt = 0;            byte ident[] = ident62.getBytes();          for ( int i = ident.length - 1; i >= 0; i-- ) {              int num = 0;              if ( ident[i] > 48 && ident[i] <= 57 ) {                  num = ident[i] - 48;              }              else if ( ident[i] >= 65 && ident[i] <= 90 ) {                  num = ident[i] - 65 + 10;              }              else if ( ident[i] >= 97 && ident[i] <= 122 ) {                  num = ident[i] - 97 + 10 + 26;              }              keisu = (int) java.lang.Math.pow( (double) base, (double) cnt );              decimal += num * keisu;              cnt++;          }          return String.format( "%08d", decimal );      }            /**      * @param args      */      public static void main(String[] args) {          // TODO Auto-generated method stub          System.out.println("62System=" +_10_to_62(Integer.parseInt("35174605"), 5));          System.out.println("10System=" +convertBase62ToDecimal("2NaWL"));      }          }
运行结果：
62System=2NaWL
10System=35174605
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