Integration

Spring Fory

spring-fory provides Spring MVC message converters, Spring WebFlux codecs, and Spring Boot auto-configuration starters for Fory JSON. It supports ordinary JSON request and response bodies, with streaming JSON and NDJSON support in WebFlux.

See the project's installation and usage guide to select the adapter or starter matching your Spring version and configure your application.

Kotlin integration

Use jsonTypeRef<Any?>(kType) when a framework supplies a Kotlin KType at runtime and the callback cannot use a reified type argument. The supplied KType determines the complete JSON type, including nested generic arguments and nullability. Any? is only the callback's static view of the value; it does not replace the supplied type with a dynamic JSON schema.

Obtaining a KType from a Kotlin function or a Java Method requires the application's kotlin-reflect dependency. Match its version to the application's Kotlin version:

dependencies {
  implementation(kotlin("reflect"))
}

For example, discover and retain a controller method's response type:

import java.io.OutputStream
import kotlin.reflect.jvm.kotlinFunction
import org.apache.fory.json.kotlin.ForyJsonKotlin
import org.apache.fory.json.kotlin.jsonTypeRef

data class Employee(val id: Long, val name: String)
data class Response<T>(val flag: Boolean, val data: T? = null, val msg: String? = null)

class EmployeeController {
  fun employees(): Response<List<Employee>> =
    Response(true, listOf(Employee(1, "Alice")))
}

val json = ForyJsonKotlin.builder().build()
val method = EmployeeController::class.java.getMethod("employees")
val responseType = jsonTypeRef<Any?>(requireNotNull(method.kotlinFunction).returnType)

fun writeResponse(value: Any?, output: OutputStream) {
  json.writeJsonTo(value, responseType, output)
}

fun readResponse(bytes: ByteArray): Any? = json.fromJson(bytes, responseType)

Discover each declared type once and reuse its token. For request bodies, obtain the corresponding Kotlin value parameter's KType. A method with unresolved type parameters still needs its concrete type arguments before conversion; star projections and contravariant projections remain unsupported. If you select a static type more specific than Any?, the caller must ensure it matches the supplied KType.

For Spring MVC, retain the controller's Kotlin declaration when adapting the request or response to a converter. A SmartHttpMessageConverter can receive application-provided read/write hints containing that KType or its Fory type token. When an HTTP wrapper such as ResponseEntity<Response<List<Employee>>> is present, select the body type Response<List<Employee>> before constructing the token.

An AbstractHttpMessageConverter callback that supplies only the runtime object loses generic arguments. AbstractGenericHttpMessageConverter preserves Java generics, but TypeRef.of(javaType) does not restore Kotlin nullability. Neither a Java Type nor the runtime value alone can recover the full Kotlin declaration. Use jsonTypeRef(kType) after obtaining that declaration; this API does not automatically install a Spring converter.