Spring WebFlux源码学习笔记(二)

继续前面的学习

先看看WebHandler

从前面的过程中我们知道，HttpHandler将Request请求最后交给了WebHandler去处理，我们先简单学习一下WebHandler的实现类

WebHandler实现类

在WebHandler的实现类里面包含了一个装饰器对象WebHandlerDecorator，HttpWebHandlerAdapter也是继承自它

ExceptionHandlingWebHandler

WebHandler装饰器调用一个或多个WebExceptionHandlers处理webHandle过程中的错误

@Override
public Mono<Void> handle(ServerWebExchange exchange) {

	Mono<Void> completion;
	try {
		completion = super.handle(exchange); //1
	}
	catch (Throwable ex) {
		completion = Mono.error(ex);
	}

	for (WebExceptionHandler handler : this.exceptionHandlers) {
		completion = completion.onErrorResume(ex -> handler.handle(exchange, ex)); //2
	}

	return completion;
}

调用父级的去处理请求
发生异常后进行异常解析

FilteringWebHandler

FilteringWebHandler使用一个WebFilterChain去处理ServerWebExchange

1	private final DefaultWebFilterChain chain;

@Override
public Mono<Void> filter(ServerWebExchange exchange) {
	return Mono.defer(() ->
			this.currentFilter != null && this.next != null ?
					this.currentFilter.filter(exchange, this.next) :
					this.handler.handle(exchange));

这里的handle实际上是DispatcherHandler

DispatcherHandler

DispatcherHandler应该是WebFlux核心的对象，在这里完成了对请求的处理。

@Override
public Mono<Void> handle(ServerWebExchange exchange) {
	if (this.handlerMappings == null) {
		return createNotFoundError();
	}
	return Flux.fromIterable(this.handlerMappings) //1
			.concatMap(mapping -> mapping.getHandler(exchange)) //2
			.next() //3
			.switchIfEmpty(createNotFoundError()) //4
			.flatMap(handler -> invokeHandler(exchange, handler)) //5
			.flatMap(result -> handleResult(exchange, result)); //6
}