如何用println 输出8位二进制码？

 public class DAC_OUT{
    public static void main (String args[]){
        float a[]=new float[args.length];
        float f=0;
        int t=0;
        int p;
        String b=new String();
        b=Integer.toBinaryString(t);
        for(int i=0;i<args.length;i++)
            a[i]=Float.parseFloat(args[i]);
        f=((a[0]/4)*255)/5;
        t=(int)f;
        System.out.println(f);
        System.out.println(t);
        System.out.println(Integer.toBinaryString(t));
        System.out.println(b);
    }
}

Integer.toBinaryString()方法可以变为二进制，但是如何补全前面的0？
萌新才学一个月。

/**
* @作者 尧
* @功能 String左对齐
*/
public static String padLeft(String src, int len, char ch) {
int diff = len - src.length();
if (diff <= 0) {
return src;
}

    char[] charr = new char[len];
    System.arraycopy(src.toCharArray(), 0, charr, 0, src.length());
    for (int i = src.length(); i < len; i++) {
        charr[i] = ch;
    }
    return new String(charr);
}
/**
 * @作者 尧
 * @功能 String右对齐
 */
public static String padRight(String src, int len, char ch) {
    int diff = len - src.length();
    if (diff <= 0) {
        return src;
    }

    char[] charr = new char[len];
    System.arraycopy(src.toCharArray(), 0, charr, diff, src.length());
    for (int i = 0; i < diff; i++) {
        charr[i] = ch;
    }
    return new String(charr);
}

使用
System.out.println(padRight(str, 8, '0'));