Adding server side dynamic validations in spring boot - spring-mvc

Question

I am using Spring Boot 2. I want to add certain dynamic validations at server side which should be executed in POST REST call. Can these validations be added in form of annotations at parameter level of POST method call?

Answer 1

Below code will help you to achieve server side validation.
Pojo class :
public class Data {
#NotNull
private final String someStringValue;
#Min(1)
private final int someIntValue;
#JsonCreator
public Data(#JsonProperty("someStringValue") String someStringValue, #JsonProperty("someIntValue") int someIntValue) {
this.someStringValue = someStringValue;
this.someIntValue = someIntValue;
}
public String getSomeStringValue() {
return someStringValue;
}
public int getSomeIntValue() {
return someIntValue;
}
For the validation we need a custom class containing the logic:
#Component
public class StringValueValidator {
public void validate(String language, Data data, Errors errors) {
if (!"de-DE".equals(language)) {
if (data.getSomeStringValue().length() > 140) {
errors.reject("someStringValue");
}
}
}
}
controller method :
#RequestMapping(value = "/validation", method = RequestMethod.POST)
public ResponseEntity<?> acceptData(#Valid #RequestBody Data data, Errors errors,
#RequestHeader(HttpHeaders.ACCEPT_LANGUAGE) String language) {
stringValueValidator.validate(language, data, errors);
if (errors.hasErrors()) {
return new ResponseEntity<>(createErrorString(errors), HttpStatus.BAD_REQUEST);
}
return new ResponseEntity<>(HttpStatus.OK);
}
Refer this : https://blog.codecentric.de/en/2017/11/dynamic-validation-spring-boot-validation/

Answer 2

Here is how you can achieve to defining validations in RequestBody you are receiving from client side.
Define your POJO you will receive from client side.
public class Employee implements Serializable {
private Long id;
#NotNull(message = "Name should not be null")
#NotBlank(message = "Name should be not empty")
#Size(min = 1, max = 255, message = "Name allowed max 255 characters")
private String name;
Now in your controller use #Valid annotation for #RequestBody like below.
public ResponseEntity<?> createEmployee(#Valid #RequestBody Employee employee)