Catching & Handling Jackson Exceptions with a custom message

Question

I'm hoping to to catch some jackson exceptions that are occurring in a spring-boot API I am developing. For example, I have the following request class and I want to catch the error that occurs when the "questionnaireResponse" key in the JSON request object is null or blank i.e " " in the request object.

@Validated
@JsonRootName("questionnaireResponse")
public class QuestionnaireResponse {

    @JsonProperty("identifier")
    @Valid
    private Identifier identifier = null;

    @JsonProperty("basedOn")
    @Valid
    private List<Identifier_WRAPPED> basedOn = null;

    @JsonProperty("parent")
    @Valid
    private List<Identifier_WRAPPED> parent = null;

    @JsonProperty("questionnaire")
    @NotNull(message = "40000")
    @Valid
    private Identifier_WRAPPED questionnaire = null;

    @JsonProperty("status")
    @NotNull(message = "40000")
    @NotEmptyString(message = "40005")
    private String status = null;

    @JsonProperty("subject")
    @Valid
    private Identifier_WRAPPED subject = null;

    @JsonProperty("context")
    @Valid
    private Identifier_WRAPPED context = null;

    @JsonProperty("authored")
    @NotNull(message = "40000")
    @NotEmptyString(message = "40005")
    @Pattern(regexp = "\\d{4}-(?:0[1-9]|[1-2]\\d|3[0-1])-(?:0[1-9]|1[0-2])T(?:[0-1]\\d|2[0-3]):[0-5]\\d:[0-5]\\dZ", message = "40001")
    private String authored;

    @JsonProperty("author")
    @NotNull(message = "40000")
    @Valid
    private QuestionnaireResponseAuthor author = null;

    @JsonProperty("source")
    @NotNull(message = "40000")
    @Valid
    private Identifier_WRAPPED source = null; //    Reference(Patient | Practitioner | RelatedPerson) resources not implemented

    @JsonProperty("item")
    @NotNull(message = "40000")
    @Valid
    private List<QuestionnaireResponseItem> item = null;

    public Identifier getIdentifier() {
        return identifier;
    }

    public void setIdentifier(Identifier identifier) {
        this.identifier = identifier;
    }

    public List<Identifier_WRAPPED> getBasedOn() {
        return basedOn;
    }

    public void setBasedOn(List<Identifier_WRAPPED> basedOn) {
        this.basedOn = basedOn;
    }

    public List<Identifier_WRAPPED> getParent() {
        return parent;
    }

    public void setParent(List<Identifier_WRAPPED> parent) {
        this.parent = parent;
    }

    public Identifier_WRAPPED getQuestionnaire() {
        return questionnaire;
    }

    public void setQuestionnaire(Identifier_WRAPPED questionnaire) {
        this.questionnaire = questionnaire;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public Identifier_WRAPPED getSubject() {
        return subject;
    }

    public void setSubject(Identifier_WRAPPED subject) {
        this.subject = subject;
    }

    public Identifier_WRAPPED getContext() {
        return context;
    }

    public void setContext(Identifier_WRAPPED context) {
        this.context = context;
    }

    public String getAuthored() {
        return authored;
    }

    public void setAuthored(String authored) {
        this.authored = authored;
    }

    public QuestionnaireResponseAuthor getAuthor() {
        return author;
    }

    public void setAuthor(QuestionnaireResponseAuthor author) {
        this.author = author;
    }

    public Identifier_WRAPPED getSource() {
        return source;
    }

    public void setSource(Identifier_WRAPPED source) {
        this.source = source;
    }

    public List<QuestionnaireResponseItem> getItem() {
        return item;
    }

    public void setItem(List<QuestionnaireResponseItem> item) {
        this.item = item;
    }
}

Resulting in this Jackson error:

{
    "Map": {
        "timestamp": "2018-07-25T12:45:32.285Z",
        "status": 400,
        "error": "Bad Request",
        "message": "JSON parse error: Root name '' does not match expected ('questionnaireResponse') for type [simple type, class com.optum.genomix.model.gel.QuestionnaireResponse]; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Root name '' does not match expected ('questionnaireResponse') for type [simple type, class com.optum.genomix.model.gel.QuestionnaireResponse]\n at [Source: (PushbackInputStream); line: 2, column: 3]",
    "path": "/api/optumhealth/genomics/v1.0/questionnaireResponse/create"
    }
}

Is there a way to catch and handle these exceptions (in the example JsonRootName is null/invalid), maybe similarly to @ControllerAdvice classes extending ResponseEntityExceptionHandler?

Answer 1

Try something along the lines of:

@ControllerAdvice
public class ExceptionConfiguration extends ResponseEntityExceptionHandler {

    @ExceptionHandler(JsonMappingException.class) // Or whatever exception type you want to handle
    public ResponseEntity<SomeErrorResponsePojo> handleConverterErrors(JsonMappingException exception) { // Or whatever exception type you want to handle
        return ResponseEntity.status(...).body(...your response pojo...).build();
    }

}

Which allows you to handle any type of exception and respond accordingly. If the response status is always the same just stick a @ResponseStatus(HttpStatus.some_status) on the method and call ResponseEntity.body(...)