两种方法实现10进制和62进制互转

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"));
}

}