UTF-8 与 GBK互转乱码的原因

public class CodecTest {
    public static void main(String[] args) throws UnsupportedEncodingException {

        String s = "我是中国人";
        //GBK编码后的字节
        //gbkEncode[-50, -46, -54, -57, -42, -48, -71, -6, -56, -53]
        byte[] gbkEncode = s.getBytes("GBK");
        System.out.println("gbkEncode" + Arrays.toString(gbkEncode));

        //utf-8编码后的字节
        //utfEncode[-26, -120, -111, -26, -104, -81, -28, -72, -83, -27, -101, -67, -28, -70, -70]
        byte[] utfEncode = s.getBytes("utf-8");
        System.out.println("utfEncode" + Arrays.toString(utfEncode));

        //用utf-8解码gbk编码后的字节，形成的字符串：�����й���
        String gbkDecodedByUTF = new String(gbkEncode,"utf-8");
        System.out.println(gbkDecodedByUTF);

        // 对上一步的字符串 �����й��� 用utf-8编码后的字节
        //[-17, -65, -67, -17, -65, -67, -17, -65, -67, -17, -65, -67, -17, -65, -67, -48, -71, -17, -65, -67, -17, -65, -67, -17, -65, -67]
        byte[] gbkDecodedByUTF_EncodeByUTF = gbkDecodedByUTF.getBytes("utf-8");
        System.out.println(Arrays.toString(gbkDecodedByUTF_EncodeByUTF));

        //不出意外，这里解码应该是 �����й���
        //所以，问题的源头出在 我们用 utf-8 gbk编码的字节上，形成了错误的字符。
　　　　　// 用utf-8 对错误的字符串编码和解码 都是错误的字符串，是一致的（字符串没变），形成错误的字符串的原因是 utf-8 和GBK解码的不兼容
        String gbkDecodedByUTF_EncodeByUTF_DecodeByUTF = new String(gbkEncode,"utf-8");
        System.out.println(gbkDecodedByUTF_EncodeByUTF_DecodeByUTF);
    }
}

Print：

gbkEncode[-50, -46, -54, -57, -42, -48, -71, -6, -56, -53]
utfEncode[-26, -120, -111, -26, -104, -81, -28, -72, -83, -27, -101, -67, -28, -70, -70]
�������
[-17, -65, -67, -17, -65, -67, -17, -65, -67, -17, -65, -67, -17, -65, -67, -48, -71, -17, -65, -67, -17, -65, -67, -17, -65, -67]
�������

utf-8编码格式：

ref：

字符编码笔记：ASCII，Unicode 和 UTF-8