Converting any object to a byte array in java

Question

I have an object of type X which I want to convert into byte array before sending it to store in S3  Can anybody tell me how to do this  I appreciate your help

User · Answer

To convert the object to a byte array use the  concept of Serialization and De-serialization   The complete conversion from object to byte array explained in is tutorial       http   javapapers com core-java java-serialization    Q  How can we convert object into byte array   Q  How can we serialize a object   Q  How can we De-serialize a object   Q  What is the need of serialization and de-serialization

User · Answer

As i ve mentioned in other  similar questions  you may want to consider compressing the data as the default java serialization is a bit verbose   you do this by putting a GZIPInput OutputStream between the Object streams and the Byte streams

User · Answer

Yeah  Just use binary serialization  You have to have each object use implements Serializable but it s straightforward from there   Your other option  if you want to avoid implementing the Serializable interface  is to use reflection and read and write data to from a buffer using a process this one below           Sets all int fields in an object to 0         param obj The object to operate on         throws RuntimeException If there is a reflection problem       public static void initPublicIntFields final Object obj        try          Field   fields   obj getClass   getFields           for  int idx   0  idx  lt  fields length  idx                if  fields idx  getType      int class                  fields idx  setInt obj  0                              catch  final IllegalAccessException ex           throw new RuntimeException ex              Source

User · Answer

What you want to do is called  serialization   There are several ways of doing it  but if you don t need anything fancy I think using the standard Java object serialization would do just fine    Perhaps you could use something like this   package com example   import java io ByteArrayInputStream  import java io ByteArrayOutputStream  import java io IOException  import java io ObjectInputStream  import java io ObjectOutputStream   public class Serializer        public static byte   serialize Object obj  throws IOException           try ByteArrayOutputStream b   new ByteArrayOutputStream                 try ObjectOutputStream o   new ObjectOutputStream b                    o writeObject obj                             return b toByteArray                         public static Object deserialize byte   bytes  throws IOException  ClassNotFoundException           try ByteArrayInputStream b   new ByteArrayInputStream bytes                try ObjectInputStream o   new ObjectInputStream b                    return o readObject                                       There are several improvements to this that can be done  Not in the least the fact that you can only read write one object per byte array  which might or might not be what you want    Note that  Only objects that support the java io Serializable interface can be written to streams   see java io ObjectOutputStream    Since you might run into it  the continuous allocation and resizing of the java io ByteArrayOutputStream might turn out to be quite the bottle neck  Depending on your threading model you might want to consider reusing some of the objects   For serialization of objects that do not implement the Serializable interface you either need to write your own serializer  for example using the read  write  methods of java io DataOutputStream and the get  put  methods of java nio ByteBuffer perhaps together with reflection  or pull in a third party dependency   This site has a list and performance comparison of some serialization frameworks  Looking at the APIs it seems Kryo might fit what you need

User · Answer

Use serialize and deserialize methods in SerializationUtils from commons-lang

[java] Converting any object to a byte array in java

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