java 里面的string 和byte[] 怎么互转

public class TestBytes {

    private static String FORMAT = "UTF-8";
    public static void main(String[] args) throws UnsupportedEncodingException {
        byte[] bytes = new byte[] { 50, 0, -1, 28, -24 };
        String sendString=new String(  bytes ,FORMAT);
        byte[] sendBytes= sendString.getBytes(FORMAT);

        String recString=new String(sendBytes ,FORMAT);
        byte[] mybytes=recString.getBytes(FORMAT);

        for(int i = 0 ; i < mybytes.length ; i++){
            System.out.print(" ");
            System.out.print(mybytes[i ]);
        }
    }

}

输出结果是： 50 0 -17 -65 -67 28 -17 -65 -67，为什么会不一样！？

FORMAT = "ISO-8859-1" 就可以了！