java 进制转化

 1     public static void toBinary(int num){
 2         trans(num,1,1);
 3     }
 4     public static void toHex(int num){
 5         trans(num,15,4);
 6     }
 7     public static void toOctal(int num){
 8         trans(num,7,3);
 9     }
10     public static void trans(int num,int base,int offset){
11         if(num==0){
12             System.out.println('0');
13             return;
14         }
15         char[] chs={'0','1','2','3',
16                     '4','5','6','7',
17                     '8','9','A','B',
18                     'C','D','E','F'};
19         char[] ch = new char[32];
20         int pos=ch.length;
21         while(num!=0){
22             
23             int temp = num & base;
24             ch[--pos] = chs[temp];
25             num = num >>> offset;
26         }
27         //System.out.println("pos="+pos);
28         for(int x=pos;x<ch.length;x++){
29             System.out.print(ch[x]);
30         }
31         System.out.println();
32     }