java二進制和十進制的互相轉換

public static void main(String[] args) {
        int i =101;
        int i2=i;
        i =getBinarySystem(i);
        System.out.println(i2+"=>轉換為二進制:"+i);
        i2=i;
        i=getDecimalism(i);
        System.out.println(i2+"=>二進制轉換十進制:"+i);

    }

    public static Integer getBinarySystem(Integer i){//十進制轉二進制

        if (i>255){
            new RuntimeException("轉換失敗,二進制最大的數值是255!");
        }

        String binarySystem ="";
        for (int j = 0; j <i; ) {
            if (i%2==0){
                binarySystem="0"+binarySystem;
            }else{
                binarySystem="1"+binarySystem;
            }
            i=i/2;

        }
        return Integer.parseInt(binarySystem);
    }//十進制轉二進制


    public static Integer getDecimalism(Integer i){

        if (i+"".length()>8){
            new RuntimeException("請輸入正确的二進制數字!");
        }
        int sum=0;
        int count=0;
        int s;
        int cube;
        for (int j = 0; j < i + "".length();) {
            s=i%10;
            cube=1;
            for (int k = 0; k <count; k++) {
                cube=cube*2;
            }
            count++;
            sum+=s*cube;
            i=i/10;
        }
        return sum;
    }//二進制轉換十進制