Java byte[] 转 String 陷阱

今天在将byte[] 转为String，然后再转回byte[] 时发现一个奇诡的问题。byte[]长度出现了变化。

具体代码如下：

        Map<String, Persion> map = new HashMap<String, Persion>();        map.put("cn1", new Persion("中国1", 30));        map.put("cn2", new Persion("中国2", 30));        Map<Integer, Map<String, Persion>> classes = new HashMap<Integer, Map<String, Persion>>();        classes.put(1, map);        {            Kryo kryo = new Kryo();            ByteOutputStream stream = new ByteOutputStream();            Output output = new Output(stream);            kryo.writeClassAndObject(output, classes);            output.flush();            byte[] bytes = stream.getBytes();            String str = new String(bytes,"utf-8");            byte[] bytes2 = str.getBytes("utf-8");            System.out.println(bytes.length + "\n" + str.length() + "\n" + bytes2.length);        }

输出为：

102410161036

经过试验发现原来是编码问题：

ByteOutputStream 默认的编码是 "ISO8859-1" 而非 "utf-8".

所以在从Stream获取byte并转为String时必须指定为 "ISO8859-1"编码。

            byte[] bytes = stream.getBytes();            String str = new String(bytes, "ISO8859-1");            byte[] bytes2 = str.getBytes("ISO8859-1");            System.out.println(bytes.length + "\n" + str.length() + "\n" + bytes2.length);<pre name="code" class="java">

此时输出长度均为1024。