webFlux

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Spring Boot Starter Webflux

Spring Webflux 5.3.2

ResponseBodyResultHandler

这个ResultHandler是最常用的一个,我们可以看到他在containingClass被ResponseBody标记或者方法被ResponseBody标记时生效

@Override
public boolean supports(HandlerResult result) {
    MethodParameter returnType = result.getReturnTypeSource();
    Class<?> containingClass = returnType.getContainingClass();
    return (AnnotatedElementUtils.hasAnnotation(containingClass, ResponseBody.class) ||
            returnType.hasMethodAnnotation(ResponseBody.class));
}

@Override
public Mono<Void> handleResult(ServerWebExchange exchange, HandlerResult result) {
    Object body = result.getReturnValue();
    MethodParameter bodyTypeParameter = result.getReturnTypeSource();
    return writeBody(body, bodyTypeParameter, exchange);
}

ViewResolutionResultHandler

ViewResolutionResultHandler支持的attributes比较多，它可以解析CharSequence，Rendering，Model，Map，View等

@Override
public boolean supports(HandlerResult result) {
    if (hasModelAnnotation(result.getReturnTypeSource())) {
        return true;
    }

    Class<?> type = result.getReturnType().toClass();
    ReactiveAdapter adapter = getAdapter(result);
    if (adapter != null) {
        if (adapter.isNoValue()) {
            return true;
        }
        type = result.getReturnType().getGeneric().toClass();
    }

    return (CharSequence.class.isAssignableFrom(type) ||
            Rendering.class.isAssignableFrom(type) ||
            Model.class.isAssignableFrom(type) ||
            Map.class.isAssignableFrom(type) ||
            View.class.isAssignableFrom(type) ||
            !BeanUtils.isSimpleProperty(type));
}

ServerResponseResultHandler

ServerResponseResultHandler只处理返回值为ServerResponse类型的Response，并使用内置的messageWriters和视图解析器来处理他们

@Override
public void afterPropertiesSet() throws Exception {
    if (CollectionUtils.isEmpty(this.messageWriters)) {
        throw new IllegalArgumentException("Property 'messageWriters' is required");
    }
}

@Override
public boolean supports(HandlerResult result) {
    return (result.getReturnValue() instanceof ServerResponse);
}

@Override
public Mono<Void> handleResult(ServerWebExchange exchange, HandlerResult result) {
    ServerResponse response = (ServerResponse) result.getReturnValue();
    Assert.state(response != null, "No ServerResponse");
    return response.writeTo(exchange, new ServerResponse.Context() {
        @Override
        public List<HttpMessageWriter<?>> messageWriters() {
            return messageWriters;
        }
        @Override
        public List<ViewResolver> viewResolvers() {
            return viewResolvers;
        }
    });
}