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无法使用Kotlin频道接收少量消息

kotlinx.coroutines kotlin

0

user51 · 技术社区 · 6 年前

我有下面的科特林连体衣代码。

    import kotlinx.coroutines.*
    import kotlinx.coroutines.channels.*

    fun main() = runBlocking {

        val channel =  Channel<Int>()
        val job = launch {
            for(x in 1..5) {
                println("sending $x")
                channel.send(x)
            }

            channel.close()
        }

        for (y in channel) {
            // if (!channel.isClosedForReceive && !channel.isClosedForSend)
            println( "received ${channel.receive()} isClosedForSend ${channel.isClosedForSend} isClosedForReceive ${channel.isClosedForReceive}  " )
        }
        job.join()
    }

上述程序的输出是(接收端缺少几个元素)

sending 1
sending 2
received 2 isClosedForSend false isClosedForReceive false  
sending 3
sending 4
received 4 isClosedForSend false isClosedForReceive false  
sending 5

如果我不开始排队 if (!channel.isClosedForReceive && !channel.isClosedForSend) ,我得到相同的输出,但有例外。

    sending 1
    sending 2
    received 2 isClosedForSend false isClosedForReceive false  
    sending 3
    sending 4
    received 4 isClosedForSend false isClosedForReceive false  
    sending 5
    Exception in thread "main" kotlinx.coroutines.channels.ClosedReceiveChannelException: Channel was closed
        at kotlinx.coroutines.channels.Closed.getReceiveException(AbstractChannel.kt:1081)
        at kotlinx.coroutines.channels.AbstractChannel.receiveResult(AbstractChannel.kt:577)
        at kotlinx.coroutines.channels.AbstractChannel.receive(AbstractChannel.kt:570)

我怎样才能毫无例外地得到正确的输出呢?

1 回复 | 直到 6 年前

1

2

Andrei Tanana 6 年前

for (y in channel) {
    println(y)
}