Spring WebFlux 中, request.queryParams 只能获取到 查询参数, 对于 form 提交的参数无法进行参数自动装载

处理方式有两种:

一. 自定义 ArgumentResolver, 具体如下:

实现接口 org.springframework.web.reactive.config.WebFluxConfigurer

重载 configureArgumentResolvers, 自定义 ArgumentResolver

从 ServerWebExchange.formData中查找参数值返回

@Configuration

class WebConfig : WebFluxConfigurer {

@Autowired

private lateinit var applicationContext: ConfigurableApplicationContext

override fun configureArgumentResolvers(configurer: ArgumentResolverConfigurer) {

class RequestFormDataMethodArgumentResolver(

beanFactory: ConfigurableBeanFactory,

registry: ReactiveAdapterRegistry,

useDefaultResolution: Boolean

): RequestParamMethodArgumentResolver(beanFactory, registry, useDefaultResolution) {

override fun resolveNamedValue(name: String, parameter: MethodParameter, exchange: ServerWebExchange): Any? {

var result: Any? = null

val formData = exchange.formData.block()

val values = formData[name]

if( null != values ){

result = values.takeUnless { it.size == 1 } ?: values[0]

}

return result

}

}

configurer.addCustomResolver(RequestFormDataMethodArgumentResolver(applicationContext.beanFactory, ReactiveAdapterRegistry.getSharedInstance(), true))

}

}

该方法无法绑定 @RequestParam标记的参数

查看org.springframework.web.reactive.result.method.annotation.ControllerResolver

我们的自定义参数处理器是位于列表末尾的, 对于 @RequestParam标记的参数已经有前面的处理器处理过了

二. 将参数封装在对象中

例如:

@PostMapping

fun create(name: String, password: String) { ... }

可以改成为:

@PostMapping

fun create(user: User) {println("$user.name - $user.password") }

作为对象封装将会触发spring的databinder机制

WebFlux 中实现了org.springframework.web.bind.support.WebExchangeDataBinder

在检测到不是基本参数的时候, 需要进行参数绑定动作

/**

* Combine query params and form data for multipart form data from the body

* of the request into a {@code Map} of values to use for

* data binding purposes.

* @param exchange the current exchange

* @return a {@code Mono} with the values to bind

* @see org.springframework.http.server.reactive.ServerHttpRequest#getQueryParams()

* @see ServerWebExchange#getFormData()

* @see ServerWebExchange#getMultipartData()

*/

public static Mono> extractValuesToBind(ServerWebExchange exchange) {

MultiValueMapqueryParams = exchange.getRequest().getQueryParams();

Mono> formData = exchange.getFormData();

Mono> multipartData = exchange.getMultipartData();

return Mono.zip(Mono.just(queryParams), formData, multipartData)

.map(tuple -> {

Mapresult = new TreeMap<>();

tuple.getT1().forEach((key, values) -> addBindValue(result, key, values));

tuple.getT2().forEach((key, values) -> addBindValue(result, key, values));

tuple.getT3().forEach((key, values) -> addBindValue(result, key, values));

return result;

});

}

这里可以看见, 进行参数绑定是从 queryParams, formData, multipartData 三个地方读取, 所以, 对象中的参数是可以正常绑定的

注意问题

WebFlux 官方文档中提到, formdata数据来自于 application/x-www-form-urlencoded, 所以使用以上方式实现 form data 参数绑定的, 注意了, 提交方式一定为: application/x-www-form-urlencoded, 否则, 请使用 request body