Package org.springframework.messaging.handler.annotation.support

Class PayloadMethodArgumentResolver

java.lang.Object
org.springframework.messaging.handler.annotation.support.PayloadMethodArgumentResolver
All Implemented Interfaces:
HandlerMethodArgumentResolver
public class PayloadMethodArgumentResolver extends Object implements HandlerMethodArgumentResolver
A resolver to extract and convert the payload of a message using a MessageConverter. It also validates the payload using a Validator if the argument is annotated with a Validation annotation.

This HandlerMethodArgumentResolver should be ordered last as it supports all types and does not require the Payload annotation.

Since:
5.2
Author:
Rossen Stoyanchev, Juergen Hoeller, Brian Clozel, Stephane Nicoll

  • Constructor Details

    • PayloadMethodArgumentResolver

      public PayloadMethodArgumentResolver(MessageConverter messageConverter)
      Create a new PayloadArgumentResolver with the given MessageConverter.
      Parameters:
      messageConverter - the MessageConverter to use (required)

    • PayloadMethodArgumentResolver

      public PayloadMethodArgumentResolver(MessageConverter messageConverter, @Nullable Validator validator)
      Create a new PayloadArgumentResolver with the given MessageConverter and Validator.
      Parameters:
      messageConverter - the MessageConverter to use (required)
      validator - the Validator to use (optional)

    • PayloadMethodArgumentResolver

      public PayloadMethodArgumentResolver(MessageConverter messageConverter, @Nullable Validator validator, boolean useDefaultResolution)
      Create a new PayloadArgumentResolver with the given MessageConverter and Validator.
      Parameters:
      messageConverter - the MessageConverter to use (required)
      validator - the Validator to use (optional)
      useDefaultResolution - if "true" (the default) this resolver supports all parameters; if "false" then only arguments with the @Payload annotation are supported.

  • Method Details

    • supportsParameter

      public boolean supportsParameter(MethodParameter parameter)
      Description copied from interface: HandlerMethodArgumentResolver
      Whether the given method parameter is supported by this resolver.
      Specified by:
      supportsParameter in interface HandlerMethodArgumentResolver
      Parameters:
      parameter - the method parameter to check
      Returns:
      true if this resolver supports the supplied parameter; false otherwise

    • resolveArgument

      @Nullable public Object resolveArgument(MethodParameter parameter, Message<?> message) throws Exception
      Description copied from interface: HandlerMethodArgumentResolver
      Resolves a method parameter into an argument value from a given message.
      Specified by:
      resolveArgument in interface HandlerMethodArgumentResolver
      Parameters:
      parameter - the method parameter to resolve. This parameter must have previously been passed to HandlerMethodArgumentResolver.supportsParameter(org.springframework.core.MethodParameter) which must have returned true.
      message - the currently processed message
      Returns:
      the resolved argument value, or null
      Throws:
      Exception - in case of errors with the preparation of argument values

    • isEmptyPayload

      protected boolean isEmptyPayload(@Nullable Object payload)
      Specify if the given payload is empty.
      Parameters:
      payload - the payload to check (can be null)

    • resolveTargetClass

      protected Class<?> resolveTargetClass(MethodParameter parameter, Message<?> message)
      Resolve the target class to convert the payload to.

      By default this is simply MethodParameter.getParameterType() but that can be overridden to select a more specific target type after also taking into account the "Content-Type", e.g. return String if target type is Object and "Content-Type:text/**".

      Parameters:
      parameter - the target method parameter
      message - the message being processed
      Returns:
      the target type to use
      Since:
      5.2

    • validate

      protected void validate(Message<?> message, MethodParameter parameter, Object target)
      Validate the payload if applicable.

      The default implementation checks for @jakarta.validation.Valid, Spring's Validated, and custom annotations whose name starts with "Valid".

      Parameters:
      message - the currently processed message
      parameter - the method parameter
      target - the target payload object
      Throws:
      MethodArgumentNotValidException - in case of binding errors