关于await问题
来源:7-11 协程的挂起原理分析2

骑着面包去草原
2019-07-30
老师您好!
我是学SpringBoot 的 我使用SpringBoot2.0 WebFlux
异步开启协程像这样:
mono {
val oldPartner = partnerService.findByCorpid(newPartner.corpid)
.awaitSingle() // 数据库查询
if (oldPartner != null) {
newPartner.id = oldPartner.id
}
val authInfoJSON = json.getJSONObject("auth_info")
val agentObj = authInfoJSON.getJSONArray("agent")
.getJSONObject(0)
var agent = agentService
.findByCorpidAndAgentTypeOne(newPartner.corpid, SuiteEnum.CENTER)
.awaitSingle() // 数据库查询
}
数据库使用的Mogodb Reactive
上述“数据库查询”的地方使用awaitSingle() 会不会造成线程阻塞?
mono源码 :
public fun <T> mono(
context: CoroutineContext = EmptyCoroutineContext,
block: suspend CoroutineScope.() -> T?
): Mono<T> {
require(context[Job] === null) { "Mono context cannot contain job in it." +
"Its lifecycle should be managed via Disposable handle. Had $context" }
return monoInternal(GlobalScope, context, block)
}
@Deprecated(
message = "CoroutineScope.mono is deprecated in favour of top-level mono",
level = DeprecationLevel.WARNING,
replaceWith = ReplaceWith("mono(context, block)")
) // Since 1.3.0, will be error in 1.3.1 and hidden in 1.4.0
@LowPriorityInOverloadResolution
public fun <T> CoroutineScope.mono(
context: CoroutineContext = EmptyCoroutineContext,
block: suspend CoroutineScope.() -> T?
): Mono<T> = monoInternal(this, context, block)
private fun <T> monoInternal(
scope: CoroutineScope, // support for legacy mono in scope
context: CoroutineContext,
block: suspend CoroutineScope.() -> T?
): Mono<T> = Mono.create { sink ->
val reactorContext = (context[ReactorContext]?.context?.putAll(sink.currentContext()) ?: sink.currentContext()).asCoroutineContext()
val newContext = scope.newCoroutineContext(context + reactorContext)
val coroutine = MonoCoroutine(newContext, sink)
sink.onDispose(coroutine)
coroutine.start(CoroutineStart.DEFAULT, coroutine, block)
}
private class MonoCoroutine<in T>(
parentContext: CoroutineContext,
private val sink: MonoSink<T>
) : AbstractCoroutine<T>(parentContext, true), Disposable {
var disposed = false
override fun onCompleted(value: T) {
if (!disposed) {
if (value == null) sink.success() else sink.success(value)
}
}
override fun onCancelled(cause: Throwable, handled: Boolean) {
if (!disposed) {
sink.error(cause)
} else if (!handled) {
handleCoroutineException(context, cause)
}
}
override fun dispose() {
disposed = true
cancel()
}
override fun isDisposed(): Boolean = disposed
}
是这个库提供的:implementation(“org.jetbrains.kotlinx:kotlinx-coroutines-reactor:1.3.0-RC”)
写回答
1回答
-
bennyhuo
2019-07-30
这个我不熟。。。它是用协程实现的?如果是suspend方法,就看他怎么调度了042019-07-30
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