org.springframework.core.MethodParameter#getParameterType ( )源码实例Demo

/**
 * Delegate to the {@link WebArgumentResolver} instance.
 * @throws IllegalStateException if the resolved value is not assignable
 * to the method parameter.
 */
@Override
@Nullable
public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
		NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {

	Class<?> paramType = parameter.getParameterType();
	Object result = this.adaptee.resolveArgument(parameter, webRequest);
	if (result == WebArgumentResolver.UNRESOLVED || !ClassUtils.isAssignableValue(paramType, result)) {
		throw new IllegalStateException(
				"Standard argument type [" + paramType.getName() + "] in method " + parameter.getMethod() +
				"resolved to incompatible value of type [" + (result != null ? result.getClass() : null) +
				"]. Consider declaring the argument type in a less specific fashion.");
	}
	return result;
}
 

/**
 * Resolves the arguments for the given method. Delegates to {@link #resolveCommonArgument}.
 */
private Object[] resolveHandlerArguments(Method handlerMethod, Object handler,
		NativeWebRequest webRequest, Exception thrownException) throws Exception {

	Class<?>[] paramTypes = handlerMethod.getParameterTypes();
	Object[] args = new Object[paramTypes.length];
	Class<?> handlerType = handler.getClass();
	for (int i = 0; i < args.length; i++) {
		MethodParameter methodParam = new SynthesizingMethodParameter(handlerMethod, i);
		GenericTypeResolver.resolveParameterType(methodParam, handlerType);
		Class<?> paramType = methodParam.getParameterType();
		Object argValue = resolveCommonArgument(methodParam, webRequest, thrownException);
		if (argValue != WebArgumentResolver.UNRESOLVED) {
			args[i] = argValue;
		}
		else {
			throw new IllegalStateException("Unsupported argument [" + paramType.getName() +
					"] for @ExceptionHandler method: " + handlerMethod);
		}
	}
	return args;
}
 

@Override
public Mono<Object> resolveArgument(
		MethodParameter parameter, BindingContext bindingContext, ServerWebExchange exchange) {

	Class<?> entityType = parameter.getParameterType();
	return readBody(parameter.nested(), parameter, false, bindingContext, exchange)
			.map(body -> createEntity(body, entityType, exchange.getRequest()))
			.defaultIfEmpty(createEntity(null, entityType, exchange.getRequest()));
}
 

private boolean methodParameterSupports(Method method) {
	boolean supports = false;
	for (int i = 0; i < method.getParameterCount(); i++) {
		MethodParameter methodParameter = MethodParameter.forExecutable(method, i);
		Class<?> parameterType = methodParameter.getParameterType();
		if (parameterType.equals(KStream.class) || parameterType.equals(KTable.class)
				|| parameterType.equals(GlobalKTable.class)) {
			supports = true;
		}
	}
	return supports;
}
 

@Override
public boolean supportsReturnType(MethodParameter returnType) {
	Class<?> bodyType = ResponseEntity.class.isAssignableFrom(returnType.getParameterType()) ?
			ResolvableType.forMethodParameter(returnType).getGeneric().resolve() :
			returnType.getParameterType();

	return (bodyType != null && (ResponseBodyEmitter.class.isAssignableFrom(bodyType) ||
			this.reactiveHandler.isReactiveType(bodyType)));
}
 

@Override
public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType, Message<?> message)
		throws Exception {

	HandlerMethodReturnValueHandler handler = getReturnValueHandler(returnType);
	if (handler == null) {
		throw new IllegalStateException("No handler for return value type: " + returnType.getParameterType());
	}
	if (logger.isTraceEnabled()) {
		logger.trace("Processing return value with " + handler);
	}
	handler.handleReturnValue(returnValue, returnType, message);
}
 

/**
 * Set {@link ModelAndViewContainer#setRequestHandled(boolean)} to
 * {@code false} to indicate that the method signature provides access
 * to the response. If subsequently the underlying method returns
 * {@code null}, the request is considered directly handled.
 */
@Override
public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
		NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {

	if (mavContainer != null) {
		mavContainer.setRequestHandled(true);
	}

	HttpServletResponse response = webRequest.getNativeResponse(HttpServletResponse.class);
	Class<?> paramType = parameter.getParameterType();

	if (ServletResponse.class.isAssignableFrom(paramType)) {
		Object nativeResponse = webRequest.getNativeResponse(paramType);
		if (nativeResponse == null) {
			throw new IllegalStateException(
					"Current response is not of type [" + paramType.getName() + "]: " + response);
		}
		return nativeResponse;
	}
	else if (OutputStream.class.isAssignableFrom(paramType)) {
		return response.getOutputStream();
	}
	else if (Writer.class.isAssignableFrom(paramType)) {
		return response.getWriter();
	}
	else {
		// should not happen
		Method method = parameter.getMethod();
		throw new UnsupportedOperationException("Unknown parameter type: " + paramType + " in method: " + method);
	}
}
 

@Override
public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
    JsonParam jsonParam = parameter.getParameterAnnotation(JsonParam.class);
    String object = webRequest.getParameter(jsonParam.value());
    if (null != object) {
        Class type = jsonParam.type() != Void.class ? jsonParam.type() : parameter.getParameterType();
        return fastJsonHttpMessageConverter.readByString(type, object);
    }
    return null;
}
 

@Override
public Object resolveArgument(MethodParameter parameter, Message<?> message) throws Exception {
	Class<?> paramType = parameter.getParameterType();
	NamedValueInfo namedValueInfo = getNamedValueInfo(parameter);

	Object arg = resolveArgumentInternal(parameter, message, namedValueInfo.name);
	if (arg == null) {
		if (namedValueInfo.defaultValue != null) {
			arg = resolveDefaultValue(namedValueInfo.defaultValue);
		}
		else if (namedValueInfo.required && !parameter.getParameterType().getName().equals("java.util.Optional")) {
			handleMissingValue(namedValueInfo.name, parameter, message);
		}
		arg = handleNullValue(namedValueInfo.name, arg, paramType);
	}
	else if ("".equals(arg) && namedValueInfo.defaultValue != null) {
		arg = resolveDefaultValue(namedValueInfo.defaultValue);
	}

	if (!ClassUtils.isAssignableValue(paramType, arg)) {
		arg = this.conversionService.convert(
				arg, TypeDescriptor.valueOf(arg.getClass()), new TypeDescriptor(parameter));
	}

	handleResolvedValue(arg, namedValueInfo.name, parameter, message);

	return arg;
}
 

@Override
public boolean supportsReturnType(MethodParameter returnType) {
	Class<?> type = returnType.getParameterType();
	return (DeferredResult.class.isAssignableFrom(type) ||
			ListenableFuture.class.isAssignableFrom(type) ||
			CompletionStage.class.isAssignableFrom(type));
}
 

/**
 * Evaluate the {@code Predicate} on the method parameter type or on
 * the generic type within a reactive type wrapper.
 */
protected boolean checkParameterType(MethodParameter parameter, Predicate<Class<?>> predicate) {
	Class<?> type = parameter.getParameterType();
	ReactiveAdapter adapter = getAdapterRegistry().getAdapter(type);
	if (adapter != null) {
		assertHasValues(adapter, parameter);
		type = parameter.nested().getNestedParameterType();
	}
	return predicate.test(type);
}
 

/**
 * Evaluate the {@code Predicate} on the method parameter type or on
 * the generic type within a reactive type wrapper.
 */
protected boolean checkParameterType(MethodParameter parameter, Predicate<Class<?>> predicate) {
	Class<?> type = parameter.getParameterType();
	ReactiveAdapter adapter = getAdapterRegistry().getAdapter(type);
	if (adapter != null) {
		assertHasValues(adapter, parameter);
		type = parameter.nested().getNestedParameterType();
	}
	return predicate.test(type);
}
 

@Override
protected void handleMissingValue(String name, MethodParameter parameter, Message<?> message) {
	throw new MessageHandlingException(message, "Missing path template variable '" + name +
			"' for method parameter type [" + parameter.getParameterType() + "]");
}
 

@Override
public boolean canResolve(final MethodParameter methodParameter) {
    final Class<?> parameterType = methodParameter.getParameterType();
    return long.class.isAssignableFrom(parameterType) || Long.class.isAssignableFrom(parameterType);
}
 

@Override
protected void handleMissingValue(String headerName, MethodParameter parameter, Message<?> message) {
	throw new MessageHandlingException(message, "Missing header '" + headerName +
			"' for method parameter type [" + parameter.getParameterType() + "]");
}
 

@Override
public boolean supportsParameter(MethodParameter parameter) {
	Class<?> clazz = parameter.getParameterType();
	return clazz == MiaoshaUserEntity.class;
}
 

@Override
public boolean supportsParameter(MethodParameter parameter) {
	return (HttpEntity.class == parameter.getParameterType() ||
			RequestEntity.class == parameter.getParameterType());
}
 

@Override
public boolean canResolve(final MethodParameter methodParameter) {
    final Class<?> parameterType = methodParameter.getParameterType();
    return Channel.class.isAssignableFrom(parameterType);
}
 

/**
 * Return the type of the value to be written to the response. Typically this is
 * a simple check via getClass on the value but if the value is null, then the
 * return type needs to be examined possibly including generic type determination
 * (e.g. {@code ResponseEntity<T>}).
 */
protected Class<?> getReturnValueType(@Nullable Object value, MethodParameter returnType) {
	return (value != null ? value.getClass() : returnType.getParameterType());
}
 

/**
 * Return the type of the value to be written to the response. Typically this is
 * a simple check via getClass on the value but if the value is null, then the
 * return type needs to be examined possibly including generic type determination
 * (e.g. {@code ResponseEntity<T>}).
 */
protected Class<?> getReturnValueType(@Nullable Object value, MethodParameter returnType) {
	return (value != null ? value.getClass() : returnType.getParameterType());
}