Kotlin 协程 异常与取消

Posted 2022-08-23 安果移不动

    @Test
    fun `test cancel and exception`() = runBlocking<Unit> 
        val job1 = launch 
            val child = launch 
                try 
                    delay(Long.MAX_VALUE)
                 finally 
                    println("Child is cancelled.")
                
            
            yield()
            println("取消子协程")
            child.cancelAndJoin()
            yield()
            println("父协程没有被取消")

        

        job1.join()

    

取消的时候如果伴随其他的异常。。那么执行顺序是这样的

    @Test
    fun `test cancel and exception2`() = runBlocking<Unit> 
        val coroutineExceptionHandler = CoroutineExceptionHandler  _, exception ->
            println("Caught $exception")
        
        val job = GlobalScope.launch(coroutineExceptionHandler) 
            launch 
                try 
                    delay(Long.MAX_VALUE)
                 finally 
                    withContext(NonCancellable) 
                        println("children are cancel ,but exception is not handled until all children terminate")
                        delay(100)
                        println("The first child finished it's non cancellable block")
                    
                
            

            launch 
                delay(10)
                println("Second child throws an exception")
                throw ArithmeticException()
            

        
        job.join()
    

 

 也不难理解

取消的本身就伴随一个异常的 就是

JobCancellationException