Validating Post Json Data Spring Boot-CodePudding

Controller

@RequestMapping(value="/create", method=RequestMethod.POST, consumes={"application/json"})
public Alien addDetails(@RequestBody Alien alien){
return repo.save(alien);
}

Alien.java

@Entity

public class Alien{
@Id
private int id;
private String name;
private String planet;
Getter and setter

Now I want to validate the post json data before saving it to the database. If any of the field is empty then the controller should return an error. For example

{"id": 1, "name": "Alien1", "planet":"Mars" }

This is acceptable json data But if there is any field is missing such as

{"name": "Alien1", "planet":"Mars" }

Then the controller should return an error and not creating the instance of Alien

I tried with @Valid @NotNull still the controller creates an empty instance of Alien and save to the database.

CodePudding user response：

You should add @Validated annotation to your controller to make @Valid annotation do the work. You should also annotate fields in your Entity with constraints.

I.e., name could be @NotBlank.

And yes, make sure that you have imported:

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-validation</artifactId>
</dependency>

Edit: In Controller, you should not accept Entity as a body. Instead, you should create a DTO object and then map it to the Entity in the service. You should also put validation constraints on the DTO!

CodePudding user response：

First of all, you should add spring boot validation dependency into your pom.xml :

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-validation</artifactId>
</dependency>

And then add annotations like @NotBlank or @NotEmpty to verify if a value is assigned to that field or not. Those annotations should be on the top of your entity's attributes which you want to validate them.For example:

public class Alien{
  @NotBlank(message="Name is mandatory")
  private String name;
}

Finally, add @Valid annotation into your controller method like:

public Alien addDetails(@Valid @RequestBody Alien alien){
 return repo.save(alien);
 }