Writing Json Schema with Bean Validation Constraints

JsonSchemaGenerator.java

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.module.jsonSchema.JsonSchema;
import com.fasterxml.jackson.module.jsonSchema.JsonSchemaGenerator;
import com.fasterxml.jackson.module.jsonSchema.customProperties.ValidationSchemaFactoryWrapper;
import lombok.Data;

@Data
class MyClass {

  @Size(min=14, max=14)
  private String reference;
  
  @Pattern(regexp = "^\\d{5}$")
  private String codeBank;
}

public static void main(String[] args) throws Exception {
  ObjectMapper mapper = new ObjectMapper();
  ValidationSchemaFactoryWrapper visitor = new ValidationSchemaFactoryWrapper();
  JsonSchemaGenerator schemaGen = new JsonSchemaGenerator(mapper);
  mapper.acceptJsonFormatVisitor(MyClass.class, visitor);
  JsonSchema jsonSchema = visitor.finalSchema();
  String mapSchemaStr = mapper.writeValueAsString(jsonSchema);
  System.out.println(mapSchemaStr);
}

// output
/*
{
  "type": "object",
  "id": "urn:jsonschema:MyClass",
  "properties": {
    "reference": {
      "type": "string",
      "maxLength": 14,
      "minLength": 14
    },
    "codeBank": {
      "type": "string",
      "pattern": "^\\d{5}$"
    }
  }
}
*/