我在玩协程,发现了一些非常奇怪的行为。我想在我的项目中使用suspendCoroutine()
. 这是显示此问题的一段代码。
在第一种情况下,当在协程中调用挂起函数时runBlocking
,来自延续的异常进入 catch 块,然后runBlocking
成功完成。但是在第二种情况下,当创建新的async
协程时,异常会通过 catch 块并导致整个程序崩溃。
package com.example.lib
import kotlinx.coroutines.async
import kotlinx.coroutines.runBlocking
import kotlin.coroutines.resumeWithException
import kotlin.coroutines.suspendCoroutine
object Test {
fun runSuccessfulCoroutine() {
runBlocking {
try {
Repository.fail()
} catch (ex: Throwable) {
println("Catching ex in runSuccessfulCoroutine(): $ex")
}
}
}
fun runFailingCoroutine() {
runBlocking {
try {
async { Repository.fail() }.await()
} catch (ex: Throwable) {
println("Catching ex in runFailingCoroutine(): $ex")
}
}
}
}
object Repository {
suspend fun fail(): Int = suspendCoroutine { cont ->
cont.resumeWithException(RuntimeException("Exception at ${Thread.currentThread().name}"))
}
}
fun main() {
Test.runSuccessfulCoroutine()
println()
Test.runFailingCoroutine()
println("We will never get here")
}
这就是控制台上打印的内容:
Catching ex in runSuccessfulCoroutine(): java.lang.RuntimeException: Exception at main
Catching ex in runFailingCoroutine(): java.lang.RuntimeException: Exception at main
Exception in thread "main" java.lang.RuntimeException: Exception at main
at com.example.lib.Repository.fail(MyClass.kt:32)
at com.example.lib.Test$runFailingCoroutine$1$1.invokeSuspend(MyClass.kt:22)
at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:32)
at kotlinx.coroutines.DispatchedTask.run(Dispatched.kt:236)
at kotlinx.coroutines.EventLoopBase.processNextEvent(EventLoop.kt:123)
at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:69)
at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:45)
at kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source)
at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:35)
at kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source)
at com.example.lib.Test.runFailingCoroutine(MyClass.kt:20)
at com.example.lib.MyClassKt.main(MyClass.kt:41)
at com.example.lib.MyClassKt.main(MyClass.kt)
Process finished with exit code 1
任何想法为什么会发生这种情况 - 它是一个错误,还是我以错误的方式使用协程?
更新:
使用coroutineScope { ... }
将缓解问题runFailingCoroutine()
fun runFailingCoroutine() = runBlocking {
try {
coroutineScope { async { fail() }.await() }
} catch (ex: Throwable) {
println("Catching ex in runFailingCoroutine(): $ex")
}
}