Javax validation not working for Hashmap with value as an Array or a List

Question

I am working on Kotlin with spring boot.

I have an entity Hours

data class Hours(
         @get: Max(value=3) val value : Long)

And in my constructor, I have the following

fun postHours(@RequestBody @Valid hours: @Valid LinkedHashMap<String,  Array<Hours>>): String {
        return service.addHours(hours)
    }

But the validation is not working at all.

I am able to send requests with value > 3 even though I have set the max value as 3. and there is no error.

Could someone tell me whats wrong here?

Use Array<@Valid Hours>

Eklavya
– Eklavya

2020-04-17 13:05:50 +00:00
Commented Apr 17, 2020 at 13:05 — Eklavya
– Eklavya, Commented Apr 17, 2020 at 13:05
Tried it. Didnt work.

Shamnad P S
– Shamnad P S

2020-04-17 15:44:32 +00:00
Commented Apr 17, 2020 at 15:44 — Shamnad P S
– Shamnad P S, Commented Apr 17, 2020 at 15:44

zpavel · Accepted Answer · 2020-04-17 16:54:47Z

1

I have a similar case that is working in Java (you can rewrite to Kotlin). Please try :

define a new bean in your configuration class annotated with @Configuration :

@Bean
public MethodValidationPostProcessor methodValidationPostProcessor() {
    return new MethodValidationPostProcessor();
}

annotate your controller with :

@RestController
@Validated

Then you can validate you class with :

postHours(@RequestBody LinkedHashMap<String, @Valid Hours> hours)

----- MODIFICATION TO PROVIDE FULL EXAMPLE -----

You can use this full example. I am using : spring-boot-starter-web 2.2.6 with lombok.

Here is the class to validate :

@Data
public class Foo {
    @Max(value = 3)
    private Integer count;
}

Controller :

@RestController
@Validated
public class FooController {
    @PostMapping("/validate")
    public String validate(@RequestBody LinkedHashMap<String, List<@Valid Foo>> foos) {
        return "foo";
    }
}

Configuration class :

@Configuration
public class AppConfig {
    @Bean
    public MethodValidationPostProcessor methodValidationPostProcessor() {
        return new MethodValidationPostProcessor();
    }
}

Controller advice (to send exception as json) :

@ControllerAdvice
public class CustomResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {
    @Data
    @AllArgsConstructor
    class ApiError {
        private HttpStatus status;
        private String message;
        private List<String> errors;
    }

    @ExceptionHandler({ ConstraintViolationException.class })
    public ResponseEntity<Object> handleConstraintViolation(ConstraintViolationException ex, WebRequest request) {
        List<String> errors = new ArrayList<>();
        for (ConstraintViolation<?> violation : ex.getConstraintViolations()) {
            errors.add(violation.getRootBeanClass().getName() + " " +
                    violation.getPropertyPath() + ": " + violation.getMessage());
        }

        ApiError apiError = new ApiError(HttpStatus.BAD_REQUEST, ex.getLocalizedMessage(), errors);
        return new ResponseEntity<>(apiError, new HttpHeaders(), apiError.getStatus());
    }
}

Test class :

@WebMvcTest(FooController.class)
public class FooControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @Autowired
    private ObjectMapper objectMapper;

    @Test
    public void test() throws Exception {
        LinkedHashMap<String, Foo> foos = new LinkedHashMap<>();
        Foo foo = new Foo();
        foo.setCount(4);
        foos.put("foo", foo);
        this.mockMvc.perform(post("/validate")
                .contentType(MediaType.APPLICATION_JSON)
                .content(objectMapper.writeValueAsString(bars)))
                .andExpect(status().isBadRequest())
                .andExpect(content().string(containsString("validate.foos[foo].<map value>[0].count: must be less than or equal to 3")));
    }
}

The unit test shows that validation inside linkedhashmap is working.

edited Apr 17, 2020 at 16:54

answered Apr 17, 2020 at 14:34

zpavel

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14 Comments

zpavel Over a year ago

i provided a full tested example in my post. please tell me if it works.

Shamnad P S Over a year ago

This will work when the value of Map is an Object, but in my case, the value part of Map is an Array.

zpavel Over a year ago

my fault i forgot this fact. i modified my post (controller and test) to validate a list. take a look on FooControllerTest at the last line.

Shamnad P S Over a year ago

I have everything except the controller advice, not working. Do I need to add the controlleradvice?

zpavel Over a year ago

Without controller advice it will throw a raw constraintvalidationexception as a response without formatting it to json. Yes you need it too. What version of spring boot do you use? Did you add spring-boot-starter-web to your pom.xml?

|

Shamnad P S · Accepted Answer · 2020-04-18 20:05:03Z

0

Finally found a fix for this. Wrote an Array wrapper class

   class ArrayWrapper<E>( elements: Array<E>?) {

        @Valid var _array: Array<E>? = elements

        override fun equals(other: Any?): Boolean {
            return if (other !is ArrayWrapper<*>) {
                false
            } else Arrays.equals(_array, other._array)
        }

        override fun hashCode(): Int {
            return Arrays.hashCode(_array)
        }
    }

and then modified the controller method like this.

fun postHours(@RequestBody @Valid hours: LinkedHashMap<String, ArrayWrapper<Hours>>): String {
        return service.addHours(hours)
    }

Now validation works perfectly!

answered Apr 18, 2020 at 20:05

Shamnad P S

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