use java8 functional

did-common/src/main/java/io/github/ehlxr/did/common/Constants.java

@@ -43,4 +43,9 @@ public class Constants {
     public static String getEnv(String key) {
         return SYS_ENV.get(key) == null ? "" : SYS_ENV.get(key);
     }
+
+    /**
+     * 编码解码 byte 数组固定长度
+     */
+    public static int DECODER_FRAMELENGTH = 100;
 }

did-common/src/main/java/io/github/ehlxr/did/common/NettyUtil.java

@@ -46,7 +46,20 @@ public class NettyUtil {
         ObjectOutputStream oos = new ObjectOutputStream(bos);
         oos.writeObject(obj);
         oos.flush();
-        return bos.toByteArray();
+
+        byte[] bytes = bos.toByteArray();
+        if (bytes.length > Constants.DECODER_FRAMELENGTH) {
+            logger.error("bytes length should not bigger than {}", Constants.DECODER_FRAMELENGTH);
+            return null;
+        } else if (bytes.length < Constants.DECODER_FRAMELENGTH) {
+            byte[] result = new byte[Constants.DECODER_FRAMELENGTH];
+
+            // 如果长度不足，填充
+            System.arraycopy(bytes, 0, result, 0, bytes.length);
+            return result;
+        }
+
+        return bytes;
     }
 
     public static Object toObject(byte[] bts) throws IOException, ClassNotFoundException {