This provides a Spring-Boot-Starter to include JsonSchemaValidation with the help of the https://github.com/networknt/json-schema-validator -library.

Include the starter into you're project.

You need to add jitpack to your pom.xml because this project is not available in the official maven repository.

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

Note: For Spring Boot < 3.0 please use 2.3.0, otherwise use 3.x.x for Spring Boot >= 3.0.

Add the json-schema-validation-starter-dependency to your pom.xml

<dependency>
    <groupId>com.github.JanLoebel</groupId>
    <artifactId>json-schema-validation-starter</artifactId>
    <version>3.0.1</version>
</dependency>

After that simply create a json-schema and put it into e.g.: resources/jsonschema/book.json. The last step is now to let your entity know that it should be validated and which schema it should use.

@JsonSchemaValidation("classpath:jsonschema/book.json")
public class Book {
    private String title;
    private String author;
}

Alternatively, you need to add this annotation in your controller like below. This is helpful when you generate your classes from a schema or can't edit them.

@RestController
@RequestMapping("/books")
public BooksConroller {
     @PostMapping
     public ResponseEntity<Book> createBook(@RequestBody @JsonSchemaValidation("classpath:jsonschema/book.json") Book bookDto) {
        //...
        return bookDto;
    }
}

The schemas are read by a bean that implements the JsonSchemaProvider interface. By default, the DefaultJsonSchemaProvider is used, which can load schemas by a URL or from the classpath. If necessary, a custom schema provider can be implemented and configured:

@ConditionalOnProperty(prefix = "json.schema.validation", name = "schemaProvider", havingValue = "custom")
@Component
public class CustomJsonSchemaProvider implements JsonSchemaProvider {
     JsonSchema loadSchema(String url) {
         // Create and return a JSON schema...
     }

    void handleValidationMessages(Collection<ValidationMessage> validationMessages) {
         // Handle validation messages...
    }
}

Configure the schema provider in application.properties:

json.schema.validation.schemaProvider=custom

Head over to http://github.com/JanLoebel/json-schema-validation-starter-example to checkout the sample project.

Please feel free to improve or modify the code and open a Pull-Request! Any contribution is welcome :)

MIT License

Copyright (c) 2019 Jan Löbel

See LICENSE file for details.