使用Objectify捕获IllegalStateException

Question

我使用Objectify 6.0.5，Ktor 1.2.6，com.google.appengine:appengine:1.9.60

我用tutorial https://github.com/objectify/objectify/wiki/Setup设置了web.xml，bootstrapper

web.xml

    ...
    <listener>
        <listener-class>com.group.Bootstrapper</listener-class>
    </listener>

    <filter>
        <filter-name>ObjectifyFilter</filter-name>
        <filter-class>com.googlecode.objectify.ObjectifyFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>ObjectifyFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    ...

助推器

class Bootstrapper : ServletContextListener {
    override fun contextInitialized(sce: ServletContextEvent?) {
        println("         contextInitialized")
        ObjectifyService.init(
            ObjectifyFactory()
        )

        ObjectifyService.register(User::class.java)
    }

    override fun contextDestroyed(sce: ServletContextEvent?) {}
}

当我调用此方法时

    fun save(entity: T) {
        ofy().save().entity(entity)
    }

我发现了错误

2020-01-05 17:55:09 ERROR Application:104 - Unhandled: GET - /test
java.lang.IllegalStateException: You must call ObjectifyService.init() before using Objectify
    at com.google.common.base.Preconditions.checkState(Preconditions.java:511) ~[guava-28.1-android.jar:?]
    at com.googlecode.objectify.ObjectifyService.factory(ObjectifyService.java:34) ~[objectify-6.0.5.jar:?]
    at com.googlecode.objectify.ObjectifyService.ofy(ObjectifyService.java:51) ~[objectify-6.0.5.jar:?]
    at com.group.dao.BaseDao.listAll(BaseDao.kt:15) ~[classes/:?]
    at com.group.ApplicationKt$module$2$2.invokeSuspend(Application.kt:50) ~[classes/:?]
    at com.group.ApplicationKt$module$2$2.invoke(Application.kt) ~[classes/:?]
    at io.ktor.util.pipeline.SuspendFunctionGun.loop(PipelineContext.kt:268) ~[ktor-utils-jvm-1.2.6.jar:1.2.6]
    at io.ktor.util.pipeline.SuspendFunctionGun.proceed(PipelineContext.kt:141) ~[ktor-utils-jvm-1.2.6.jar:1.2.6]
    at io.ktor.util.pipeline.SuspendFunctionGun.execute(PipelineContext.kt:161) ~[ktor-utils-jvm-1.2.6.jar:1.2.6]
    at io.ktor.util.pipeline.Pipeline.execute(Pipeline.kt:27) ~[ktor-utils-jvm-1.2.6.jar:1.2.6]
    at io.ktor.routing.Routing.executeResult(Routing.kt:147) ~[ktor-server-core-1.2.6.jar:1.2.6]
...

我使用'gcloud beta模拟器datastore start‘来运行数据存储。它绝对可以运行。可能是连接不上了吧？

当我使用appengineRun运行应用程序时，数据存储也在运行吗？

Answer 1

问题是ktor使用协程。默认情况下，协程在线程池中运行，并且ObjectifyFilter只对接收请求的线程有效。我会使用这个变通方法，直到我找到更好的方法：

get(path) {
    withContext(Dispatchers.Unconfined) {
        val content = page.doGet()
        call.respond(content)
    }
}

Unconfined调度程序在启动它的同一线程中运行协程，至少在第一次挂起之前是这样。