java通过移位转16进制

public class Main {
    public static void main(String []args)
    {
        Main main = new Main();
        System.out.println("main: "+main.Hex(j));
        System.out.println("Sys: "+Integer.toHexString(j));
    }
    private String Hex(int i)
    {
        String string="";
        String temp = Integer.toBinaryString(i);
        int len = temp.length();
        System.out.println(temp);
        System.out.println(len);
        while(len%4!=0)
        {
            temp="0"+temp;
            len=temp.length();
        }
        while(len>0)
        {
            //System.out.println(len+" "+string);
            int bit = 0;
            if(temp.charAt(len-1)=='1')
            {
                bit+=1;
            }
            if(temp.charAt(len-2)=='1')
            {
                bit+=2;
            }
            if(temp.charAt(len-3)=='1')
            {
                bit+=4;
            }
            if(temp.charAt(len-4)=='1')
            {
                bit+=8;
            }
            switch (bit) {
            case 10:
                string='A'+string;
                break;
            case 11:
                string='B'+string;
                break;
            case 12:
                string='C'+string;
                break;
            case 13:
                string='D'+string;
                break;
            case 14:
                string='E'+string;
                break;
            case 15:
                string='F'+string;
                break;

            default:
                string=bit+string;
                break;
            }
            len-=4;
        }
        
        return string;
    }
}