Object serialization in Java bypasses creating this text file to store data, saving time and programming costs. The following article contains the steps to serialize an object in Java. The sample code in this article is used courtesy of The Java Developers Almanac 1.4. I am trying to serialize an object array and write it to a file named address.ser and then read back from the file, deserialize the object array and display its attributes. Sign up or log in to customize your list. More stack exchange communities company blog. By using our site, you. The serialization interface has no methods or fields and serves only to identify the semantics of being serializable.So you don't need to implement any method just declaring is enough. According to java docs. Serializability of a class is enabled by the class implementing the java.io.Serializable interface.

All standard implementations of java.util.List already implement java.io.Serializable. So even though java.util.List itself is not a subtype of java.io.Serializable, it should be safe to cast the list to Serializable, as long as you know it's one of the standard implementations like ArrayList or LinkedList. In Java, ArrayList class is serializable by default. It essentially means that we do not need to implement Serializable interface explicitly in order to serialize ArrayList. We can directly use ObjectOutputStream to serialize ArrayList, and ObjectInputStream to deserialize an arraylist object.

I've a Model object Group

I'm using Jackson to serialize this Object. Instead of serializing the whole User object in list 'members' I want to serializer just the user.getTitle() field.Basically I want a HashMap to be something like

I've written a custom serializer for this

But it's not working. How do I serialize only a field of List instead of whole User Object?

2 Answers

I suggest that you look into Jackson's Converter interface, which seems more suited to the task than creating a custom serializer.

One approach it to create a Converter instance and add it to the ObjectMapper, so that it will be used for the serialization of all User instances.

Register it on your ObjectMapper like this:

Another approach, in case you don't want to convert all User instances to String, is to annotate selected properties with a converter like this:

And have a corresponding converter that looks something like this:

Henrik Aasted SørensenHenrik Aasted Sørensen

Try like below :

Group:

User:

Custom Serializer :

Test :

Output:

JJDBarathBarath

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I am trying to serialize an object array and write it to a file named address.ser and then read back from the file, deserialize the object array and display its attributes. I tried serializing the whole arrayList at once(deserializing it in a single session while reading) and also tried serializing each object of the object array one by one(deserializing it one by one while reading). The problem is, while reading back from the address.ser file I am getting data only of the last object which was written and none other.

Here is the code snippet:

This is the code snippet for writing objects to address.ser:

This is the code snippet for reading objects from address.ser:

The final output being:

stinepike

Java Serialize List To Byte Array

3 Answers

maheshmahesh

Java Serialization

The problem is you are trying to write the object in a wrong way. You are writing each element of the ArrayList in a same file. So what is happening is a new element is replacing the old one. So write the whole List at a time liek

stinepikestinepike

Corrected Solution

You're overwriting the file for each element you attempt to serialize. Therefore, the last serialized element remains. A file of serialized data has a header, so you must write your data in one shot.

Java Serialize List Of Objects To Xml

However, it's more efficient to serialize the entire list in one shot.

Java Serialize List Of Strings

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