title: (Spring boot) How can I ignore some field from request body inside rest controller
body: <p>Suppose I have signUp method inside rest controller class looks like this.</p>
  <pre><code>  @PostMapping(&quot;/signup&quot;)
    fun authenticateSignUp(@RequestBody command: RegisterUserCommand): CompletableFuture&lt;String&gt; {
      return commandGateway.send&lt;String&gt;(command)
    }
  </code></pre>
  <p>So it requires request body which is RegisterUserCommand.</p>
  <pre><code>data class RegisterUserCommand(
    val userId: String,
    val balance: BigDecimal,
    val username: String,
    private val email: String,
    private val password: String
  )
  </code></pre>
  <p>I want to ignore some fields like userId, balance so I can generate it later inside controller like this</p>
  <pre><code>@PostMapping(&quot;/signup&quot;)
  fun authenticateSignUp(@RequestBody request: RegisterUserCommand): CompletableFuture&lt;String&gt; {
    val command = request.copy(userId = ObjectId.get().toHexString(), balance = BigDecimal.ZERO)
    return commandGateway.send&lt;String&gt;(command)
  }
  </code></pre>
  <p>Are there any annotation to ignore this field so it won't return bad request even though I didn't put userId, balance within request body</p>