Validation API

Official Doc: https://docs.jboss.org/hibernate/stable/validator/reference/en-US/html_single/?v=6.0
Article in RU: https://habr.com/ru/post/424819/ Article in EN: https://reflectoring.io/bean-validation-with-spring-boot/

Hibernate Validator is the reference implementation of the validation API.

Configuration

For main and test dirs: cp application.properties.dist application.properties

3.1. Validation API Per the JSR 380 specification, the validation-api dependency contains the standard validation APIs:

Add deps if not using Spring Boot

<dependency>
    <groupId>javax.validation</groupId>
    <artifactId>validation-api</artifactId>
    <version>2.0.0.Final</version>
</dependency>

Validation API Reference Implementation

Hibernate Validator is the reference implementation of the validation API.

To use it, we must add the following dependencies:

<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.0.2.Final</version>
</dependency>
<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator-annotation-processor</artifactId>
    <version>6.0.2.Final</version>
</dependency>

Validation (JSR 303)

All of the annotations used in the example are standard JSR annotations:

• @NotNull – validates that the annotated property value is not null
• @AssertTrue – validates that the annotated property value is true
• @Size – validates that the annotated property value has a size between the attributes min and max; can be applied to String, Collection, Map, and array properties
• @Min – vValidates that the annotated property has a value no smaller than the value attribute
• @Max – validates that the annotated property has a value no larger than the value attribute
• @Email – validates that the annotated property is a valid email address

Some annotations accept additional attributes, but the message attribute is common to all of them. This is the message that will usually be rendered when the value of the respective property fails validation.

Some additional annotations that can be found in the JSR are:

• @NotEmpty – validates that the property is not null or empty; can be applied to String, Collection, Map or Array values
• @NotBlank – can be applied only to text values and validated that the property is not null or whitespace
• @Positive and @PositiveOrZero – apply to numeric values and validate that they are strictly positive, or positive including 0
• @Negative and @NegativeOrZero – apply to numeric values and validate that they are strictly negative, or negative including 0
• @Past and @PastOrPresent – validate that a date value is in the past or the past including the present; can be applied to date types including those added in Java 8
• @Future and @FutureOrPresent – validates that a date value is in the future, or in the future including the present

Bean Validation POJO

See test: /src/test/java/hello/beanValidation/PersonTest.java

With custom annotation: /src/test/java/hello/beanValidation/customAnnotation/PersonWithCustomAnnotationTest.java

Bean Validation on class level - for validate dependencies fields

With validate two fields start and finish time: /src/test/java/hello/beanValidation/customTwoFieldsValidation/OperationTest.java

Bean Validation with MVC Controller

Entity: /src/main/java/hello/entity/beanValidation/Employee.java

    @NotNull(message = "Please provide name")
    @Column(name = "name")
    private String name;

Add to controller @Valid:

    @PostMapping("")
    public Employee newEmployee(@RequestBody @Valid Employee newEmployee) {
        return service.save(newEmployee);
    }

Testing

For testing @Valid with response must run full application.
See test: /src/test/java/hello/controller/beanValidation/EmployeeRestTemplateTest.java

When testing with @MockMvc check only status code, body - empty See test: /src/test/java/hello/controller/beanValidation/EmployeeControllerTest.java

Spring Validation

Validator: /src/main/java/hello/springValidation/service/PeopleValidator.java Test: /src/test/java/hello/springValidation/PeopleTest.java

Spring Validation for MVC controller

Example: /src/main/java/hello/controller/springValidation/PeopleController.java

1. Init binder out validator:

    @Autowired
    private PeopleValidator peopleValidator;

    @InitBinder
    protected void initBinder(WebDataBinder binder) {
        binder.setValidator(peopleValidator);
    }

2. Add in method check errors:

    @PostMapping("")
    public People create(@RequestBody @Valid People people, BindingResult bindingResult) {
        if (bindingResult.hasErrors()) {
            throw new NotValidParamsException(bindingResult.getFieldError().getCode(), INVALID_PARAMS);
        }
        return service.save(people);
    }