Working with Jackson

Jimmer objects are dynamic and not all properties of an object need to be initialized. It allows missing some properties.

Accessing an unspecified property directly in code will cause an exception.
Unspecified properties are automatically ignored in JSON serialization without exceptions.

JSON serialization is mentioned here, referring to jackson.

jimmer-core defines a jackson module: org.babyfish.jimmer.jackson.ImmutableModule which can add the ability of serialize/deserialize jimmer immutable objects for jackson.

There are two cases:

Using Spring Boot Starter

In this case, Jimmer has already registered ImmutableModule to Spring as below:
```
// Internal Jimmer code, not user code
@ConditionalOnMissingBean(ImmutableModule.class) 
@Bean
public ImmutableModule immutableModule() {
    return new ImmutableModule();
}
```
Therefore, the default ObjectMapper of Spring can already serialize/deserialize Jimmer dynamic objects, and most serialization/deserialization work is done automatically by Spring during HTTP interaction, so no extra development is required.

caution
The default JSON handling library in Spring is jackson. Don't replace it.

Using low level API

Java
Kotlin

ObjectMapper mapper = new ObjectMapper()
    .registerModule(new ImmutableModule());

TreeNode treeNode = Immutables.createTreeNode(
    draft -> draft.setName("Root Node")
);

// Serialize    
String json = mapper.writeValueAsString(treeNode);

// Deserialize
TreeNode deserializedTreeNode = 
    mapper.readValue(json, TreeNode.class);

val mapper = ObjectMapper()
    .registerModule(ImmutableModule())

val treeNode = TreeNode {
    name = "Root Node"
}

// Serialize
val json = mapper.writeValueAsString(treeNode)

// Deserialize
val deserializedTreeNode = 
    mapper.readValue(json, TreeNode::class.java)

tip

For serialization, there is a handy way which is the toString method of jimmer objects.