java 十进制与六十二进制

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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 stack=new Stack();
         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"));
	}
	

}