//        byte to String
        byte b = 0x08;
        int i = ((Byte)b).intValue();
        System.out.println(i);
        String s = Integer.toBinaryString(i);
        System.out.println(s);
//        String to byte
        String s2 = "00001000";
//        按二进制转换s2
        byte b2 = Byte.parseByte(s2, 2);
        System.out.println(b2);

------解决方案--------------------
直接上代码了
刚才测了下,在不打印的情况下，两个方法执行一次用时2.4013782070000002E-6秒

Java code

public class Test {
    public static void main(String[] args) {
        long start = System.nanoTime();
        //不输出结果运行1000000次
        for(int i = 0;i < 1e6;i++){
            byte[] bys = {0x01,0x02,0x03};
            bytesToString(bys);
            //System.out.println(bytesToString(bys));
            byte[] bys2 = stringTobytes("000010000000100100001010");
            //for(byte b:bys2)
                //System.out.println(b);
        }
        long end = System.nanoTime();
        System.out.println("time:" + (end - start) / 1e9 + "s");
        System.out.println("pre time:" + (end - start) / 1e9 / 1e6 + "s");
    }
    
    private static String bytesToString(byte[] bys){
        StringBuffer sb = new StringBuffer();
        for(int i = 0;i < bys.length;i++){
            String s = String.valueOf(bys[i]);
            for(int j = 0;j < Byte.SIZE - s.length();j++)
                sb.append("0");
            sb.append(s);            
        }
        return sb.toString();
    }
    
    private static byte[] stringTobytes(String str){
        byte[] bys = new byte[str.length() / Byte.SIZE];
        for(int i = 0;i < bys.length;i++){
            String s = str.substring(i * Byte.SIZE,(i + 1) * Byte.SIZE);
            for(int j = 0;j < s.length();j++){
                if(s.charAt(j) == '1')
                    bys[i] |= (1 << (Byte.SIZE - j - 1));
            }
        }
        return bys;
    }
}