JSON 2 POJO offline - java

I would like to generate a Java object from JSON. All examples on the Internet use an ObjectMapper class and a Java class to serialize the JSON too.
The JSON is complicated, and I don't want to define the Java class by hand with annotations for properties.
I want to be able to generate the Java class with Jackson or GSON annotations with the JSON data with software.
The website jsonschema2pojo does this for you online. My JSON is offline in a private network where I cannot use jsonschema2pojo for a complicated JSON string.
How can I replicate the jsonschema2pojo code in my own environment? Is it easy to do with Jackson, or GSON?

I don't think Jackson or GSON have this support yet but lots of people have contributed code according to your requirement.
You can check:
https://github.com/astav/JsonToJava
or
https://github.com/wotifgroup/json2pojo
Moreover maybe you can try downloading that dependent jar manually and add it in your MAVEN repository manually.

You can use jsonschema2pojo offline. It can be used as a Maven plugin, a Gradle plugin, and command line tool or an Ant task.
At the bottom of the page at www.jsonschema2pojo.org you'll see links to help with each of these methods.

Related

Is it possible to: Java DTO --> Swagger --> Java DTO?

In a very big Java app with lot's of DTOs, I want to export to an external project only the DTOs that are relevant to REST calls, and even better to export a part of them (the minimum required for REST calls).
The project uses Swagger and I am wondering if it is possible to take the output of Swagger (uses Java DTOs to create JSON\YAML files), which have the exact content I need, as an input to generate new Java DTO files. The generated files will be only those needed for REST and I will be able to easily export them.
Is this possible?
If not, what is the best approach to do that?
Maybe check out swagger.generator.io where you can generate a whole client library (including DTO classes) for your specified swagger definition file. For documentation please refer to their github page. You can also do the generation of the API client locally utizing the swagger codegen tools.

Serialize POJO to JSON through a provider

What is a common way to serialize Java Beans to JSON in a automatic fashion? The #Produces(MediaType.APPLICATION_JSON) doesnt seem to handle the conversion under the hood. Do we create our own JSON Providers or is there another way? Currently im trying to handle it via the ContextResolver:
https://docs.oracle.com/javaee/7/api/javax/ws/rs/ext/ContextResolver.html
It is my understanding that the #Produces annotation should help create the expected output if a java object is returned from one of the resource class methods.
You do not have to code the jackson based provider yourself.
In apache karaf you can simply install the feature aries-jax-rs-whiteboard-jackson.
If you are not using karaf you can install the bundles from the feature yourself:
https://github.com/apache/aries-jax-rs-whiteboard/blob/master/jax-rs.features/src/main/feature/feature.xml

How to implement JSON functionality in a shared library without hard-wiring third party dependencies

I'm writing a class to provide some logging output in JSON format.
One issue is that the various Java projects I work on already use JSON and have dependencies on 3rd party libraries like gson or Jackson.
The work the class needs to perform is quite small and I figured it should be easy to avoid creating a new dependency on any particular JSON library, analagous to SLF4j which picks up whatever logging framework is already present.
My plan is that the class would pick up a JSON engine and use it, or throw a "missing JSON library" exception at start-up.
Does this already exists? I can't find anything on the net.
Is the Java JDK service provider java.util.ServiceLoader suitable?
It seemed easy enough to implement when I used it to plug in a java.nio.file.spi.FileTypeDetector for mime type detection with Apache Tika (best explained on this useful blog post.
You could try Class.forName(), passing the full name of the core class for Gson, Jackson, or whatever other JSON library is in use. If the class is not on the classpath, you will get a ClassNotFound exception. If you did this test only once, the cost would be reasonable.

Rest api testing using java POJO and jackson

I am new to webservices testing and i am trying to test a webservice which returns both a JSON as well as XML output .
my management wants me to do this with jackson jersery and other libraries for XML
i created a java client using jersey and i got the response . i am not sure how to validate this response against a POJO class .
i am not entitled to use sophisticated libraries like rest assured or json path . can some one explain me how will i validate/assert both json and xml response against a POJO step by step and make my life easy ?
kindly help
also list down the libraries needed for handling xml responses too ?
Karate is a new test-framework for testing web-services, and it supports both JSON and XML. You don't need to know Java and it does not need you to add any libraries. The documentation is extensive and the demo project has examples.
Disclaimer: am dev.

How to serialize/deserialize in both JSON and XML format in Java?

Have a bunch of classes which I need to do serialize and deserialize from/to JSON/XML at the same time. Which library you recommend to this task?
I like Jackson for JSON, and XStream for XML. We use them both in a product and they're pretty rugged. Jackson is very fast.
Update: #radai suggests the Simple XML library, which looks pretty interesting.
For xml we use simple (simple.sourceforge.net)
You can do both with Jackson: core package handles JSON, and xml-databinding extension module can do XML.
There are other modules that support BSON and CSV, as well; Jackson is becoming a general-purpose data-binding tool.
Here's a good resource for json
Here's a good resource for processing xml

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