java - 在 Hazelcast 中使用快速聚合时无法创建自定义谓词

Question

我正在创建一个自定义谓词。它接受一个整数并将其与映射的值进行比较。

public class LocationPredicate implements Predicate<Key, Portable> {

    private int rssi;

    public LocationPredicate() {
    }

    public LocationPredicate(int rssi) {
        this.rssi = rssi;
    }

    @Override
    public boolean apply(Entry<Key, Aortable> arg0) {
        return false;
        //int val = arg0.getValue().getData().getLocation().getRssiVal();
        //return (rssi == val ) ;
    }

}

当我运行该程序时，出现以下错误:

Exception in thread "main" com.hazelcast.nio.serialization.HazelcastSerializationException: java.lang.ClassNotFoundException: com.snmpapp.main.LocationPredicate
    at com.hazelcast.internal.serialization.impl.JavaDefaultSerializers$JavaSerializer.read(JavaDefaultSerializers.java:224)
    at com.hazelcast.internal.serialization.impl.StreamSerializerAdapter.read(StreamSerializerAdapter.java:48)
    at com.hazelcast.internal.serialization.impl.AbstractSerializationService.toObject(AbstractSerializationService.java:184)
    at com.hazelcast.client.impl.protocol.task.map.MapAggregateWithPredicateMessageTask.getPredicate(MapAggregateWithPredicateMessageTask.java:45)
    at com.hazelcast.client.impl.protocol.task.map.AbstractMapQueryMessageTask.call(AbstractMapQueryMessageTask.java:87)
    at com.hazelcast.client.impl.protocol.task.AbstractCallableMessageTask.processMessage(AbstractCallableMessageTask.java:35)
    at com.hazelcast.client.impl.protocol.task.AbstractMessageTask.initializeAndProcessMessage(AbstractMessageTask.java:123)
    at com.hazelcast.client.impl.protocol.task.AbstractMessageTask.run(AbstractMessageTask.java:103)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
    at com.hazelcast.util.executor.HazelcastManagedThread.executeRun(HazelcastManagedThread.java:64)
    at com.hazelcast.util.executor.HazelcastManagedThread.run(HazelcastManagedThread.java:80)
    at ------ submitted from ------.(Unknown Source)
    at com.hazelcast.client.spi.impl.ClientInvocationFuture.resolveAndThrowIfException(ClientInvocationFuture.java:95)
    at com.hazelcast.client.spi.impl.ClientInvocationFuture.resolveAndThrowIfException(ClientInvocationFuture.java:32)
    at com.hazelcast.spi.impl.AbstractInvocationFuture.get(AbstractInvocationFuture.java:155)
    at com.hazelcast.client.spi.ClientProxy.invoke(ClientProxy.java:172)
    at com.hazelcast.client.proxy.ClientMapProxy.aggregate(ClientMapProxy.java:1356)
    at com.snmpapp.main.Main.main(Main.java:370)
Caused by: java.lang.ClassNotFoundException: com.aruba.acp.snmpapp.main.LocationPredicate
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at com.hazelcast.nio.ClassLoaderUtil.tryLoadClass(ClassLoaderUtil.java:149)
    at com.hazelcast.nio.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:123)
    at com.hazelcast.nio.IOUtil$ClassLoaderAwareObjectInputStream.resolveClass(IOUtil.java:522)
    at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1613)
    at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1518)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1774)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371)
    at com.hazelcast.internal.serialization.impl.JavaDefaultSerializers$JavaSerializer.read(JavaDefaultSerializers.java:219)
    at com.hazelcast.internal.serialization.impl.StreamSerializerAdapter.read(StreamSerializerAdapter.java:48)
    at com.hazelcast.internal.serialization.impl.AbstractSerializationService.toObject(AbstractSerializationService.java:184)
    at com.hazelcast.client.impl.protocol.task.map.MapAggregateWithPredicateMessageTask.getPredicate(MapAggregateWithPredicateMessageTask.java:45)
    at com.hazelcast.client.impl.protocol.task.map.AbstractMapQueryMessageTask.call(AbstractMapQueryMessageTask.java:87)
    at com.hazelcast.client.impl.protocol.task.AbstractCallableMessageTask.processMessage(AbstractCallableMessageTask.java:35)
    at com.hazelcast.client.impl.protocol.task.AbstractMessageTask.initializeAndProcessMessage(AbstractMessageTask.java:123)
    at com.hazelcast.client.impl.protocol.task.AbstractMessageTask.run(AbstractMessageTask.java:103)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
    at com.hazelcast.util.executor.HazelcastManagedThread.executeRun(HazelcastManagedThread.java:64)
    at com.hazelcast.util.executor.HazelcastManagedThread.run(HazelcastManagedThread.java:80)

我有点困惑。我需要在服务器上创建谓词吗？我作为 Hcast 客户端运行，客户端正在创建谓词。

据我所知，当您创建谓词时，它会作为序列化对象发送到 hazelcast 服务器。

此外，我尝试将谓词实现为可序列化，但没有帮助。 谢谢

Answer 1

我对 Hazelcast 没有经验，但据我所知，在序列化和反序列化过程中，您可以传输状态(在本例中为成员变量)，但不能传输行为(您对 apply 方法的实际实现)。不知何故(我对这项技术没有经验)你应该将你的类提供给 Hazelcast 的类加载器(也许复制到类路径)。祝你好运!