The application built in this guide is quite simple: the user can add elements in a list using a form and the list is updated.
We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.
The solution is located in the rest-json-quickstart directory. Nothing fancy.
One important thing to note is that having a default constructor is required by the JSON serialization layer. The Jackson is pretty straightforward and you just need to define your endpoints using the JAX-RS annotations. If you set this you will need to add Produces MediaType. It easy allow to narrow down the of JAX-RS providers which can be seen as converters included in the native executable. You can restore the default behavior of Jackson by setting quarkus. The default behaviour of Jackson can be restored by setting quarkus.
If you want to change the format for a single field, you can use the JsonFormat annotation. The simplest and suggested approach is to define a CDI bean of type io. ObjectMapperCustomizer inside of which any Jackson configuration can be dates. Users can even provide their own ObjectMapper bean if they so choose. If this is done, it is very important to manually inject and apply all io. Failure to do so will prevent Jackson specific customizations provided by various extensions from being applied. Following the same approach as described in the section, JSON-B can be configured using a io.
If for example a custom serializer named FooSerializer for type com. A more advanced option would be to directly provide a bean of javax. JsonbConfig with a Dependent scope or in the extreme case to provide a bean of type javax. Jsonb with a Singleton scope. If the latter approach is leveraged it is very important to manually inject and apply all io. Failure to do so will prevent JSON-B specific customizations provided by various extensions from being applied. Running it is as simple as executing. JSON serialization libraries use Java reflection to get the properties of an object and serialize them.
When using native executables with GraalVM, all classes that will be used with reflection need to be registered.
The good news is that Quarkus does that work for you most of the time. Quarkus performs some magic when it is capable of inferring the serialized types from the REST methods. Response comes with some nice perks:.
It is not possible for Quarkus to determine at build time the type included in the Response as the information is not available. As mentioned above, the issue is that Quarkus was not able to determine the Legume class will require some reflection by analyzing the REST endpoints. The JSON serialization library tries to get easy list of fields of Legume and gets an empty list so it does not serialize the fields' data. At the moment, when JSON-B or Jackson tries to get the list of fields of dates class, if the class is not registered for reflection, no exception will be thrown.
GraalVM will simply return an empty list of Jackson.
We can register Legume for reflection manually by adding the RegisterForReflection annotation on our Legume class:. You can return reactive types to handle asynchronous processing. Quarkus recommends the usage of Mutiny to write reactive and asynchronous code. Use Uni when you have a single result. Use Multi when you have multiple items that may be emitted asynchronously. More details about Mutiny can be found in Mutiny - an intuitive reactive programming library. These filters are suitable for processing the metadata associated with a message: HTTP headers, query parameters, media type, and other metadata.
They also have the capability to abort the request processing, for instance when the user does not have the permissions to access the endpoint. We can do that by implementing ContainerRequestFilter and annotating it with the Provider annotation:. Cross-origin resource sharing CORS is a mechanism that allows restricted resources on a web to be requested from another domain outside the domain from which the first dates was served.
Quarkus comes with a CORS filter. Quarkus comes with GZip support even though it is not enabled by default. The following configuration knobs allow to configure GZip support. Once GZip support has been enabled you can use it on an endpoint by Jackson the org. GZIP annotation to your endpoint method. If you want to compress everything then we recommended that easy use the quarkus.
Quarkus - writing json rest services
Quarkus provides an extension called quarkus-resteasy-multipart to make things easier for you. Configuration property fixed at build time - All other configuration properties are overridable at runtime. Configuration property.
Default charset. As a result, certain classes, such as HttpServletRequest are not always available for injection. One important consequence of this consideration is that they share the same list of providers in the JAX-RS meaning of the word. For instance, if you declare a WriterInterceptorit will by default intercept both the servers calls and the client calls, which might not be the desired behavior. Configuration via an application-supplied subclass of Application is supported, but not required. If multiple JAX-RS Application classes are defined, the build will fail with the message Multiple classes have been annotated with ApplicationPath which is currently not supported.
This makes all resource-classes available via easy application-path as defined by quarkus. Moreover, it only relies on the methods getClasses and getSingletons to filter out the annotated resource, provider and feature classes. Finally the objects returned by the method getSingletons are ignored, only the classes are took into to filter out the resource, provider and dates classes, in other words the method getSingletons is actually managed the same way as getClasses. If there is no scope annotation declared on the resource class then the scope is defaulted.
The default scope can be controlled through the quarkus. If set to true default then a single instance of a resource class is created to service all requests as defined by javax. If set to false then a new instance of the resource class is created per each request. IfBuildProfile or io. IfBuildProperty or io. In the following example, Quarkus includes the endpoint sayHello if and only if the build profile app1 has been enabled. As usual, Quarkus further Jackson things under the hood when running your application as a native executable.
Quarkus is open. All dependencies of this project are available under the Apache Software 2. This website was built with Jekyllis hosted on Github s and is completely open source. JSON is now the lingua franca between microservices. Prerequisites To complete this guide, you need:. Architecture The application built in this guide is quite simple: the user can add elements in a list using a form and the list is updated. All the information between the browser and the server are formatted as JSON.
Solution We recommend that you follow the instructions in the next sections and create the application step by step. Creating the Maven project First, we need a new project. Create a new project with the following command:. Now, edit the org. FruitResource class as follows:.
Collections; import java. LinkedHashMap; import java. Set; import javax. GET; import javax. POST; import javax. An example where a custom module needs to be registered would look like so:. ObjectMapper; import io.
ObjectMapperCustomizer; import javax. Instance; import javax. JsonbConfigCustomizer; import javax. Singleton; import javax. JsonbConfig; import javax. Dependent; import javax. Building a native executable You can build a native executable with the usual command. About serialization JSON serialization libraries use Java reflection to get the properties of an object and serialize them.