Question

我正在使用多节点hazelcast（3.11版）群集。我的用例是，在hazelcast启动期间，我希望每个成员将数据加载到Imap中。我已经在hazelcast.xml中为每个节点配置了地图存储配置。

我在hazelcast.xml中添加了地图存储配置。该文件放置在每个hazelcast节点的bin文件夹中。

每个节点的

hazelcast.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
<hazelcast
        xsi:schemaLocation="http://www.hazelcast.com/schema/config hazelcast-config-3.3.xsd"
        xmlns="http://www.hazelcast.com/schema/config" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <properties>
        <property name="hazelcast.initial.min.cluster.size">2</property>
    </properties>

<management-center enabled="true">
    http://localhost:8080/hazelcast-mancenter
</management-center>

    <network>
        <port auto-increment="true">5701</port>
        <join>
            <multicast enabled="false">
                <multicast-group>224.2.2.3</multicast-group>
                <multicast-port>2434</multicast-port>
                <multicast-timeout-seconds>1</multicast-timeout-seconds>
            </multicast>
            <tcp-ip enabled="true" connection-timeout-seconds="3">
                <member>127.0.0.1:5701</member>
                <member>127.0.0.1:5702</member>
            </tcp-ip>
        </join>
        <interfaces enabled="true">
            <interface>127.0.0.1</interface>
        </interfaces>
    </network>


<map name="testmap">
    <backup-count>1</backup-count>
    <time-to-live-seconds>0</time-to-live-seconds>
    <max-idle-seconds>0</max-idle-seconds>

    <map-store enabled="true">
        <class-name>com.bm.mapstore.OnboardingMapLoader</class-name>
        <write-delay-seconds>0</write-delay-seconds>
    </map-store>
</map>

</hazelcast>

类的代码OnboardingMapLoader是jar文件的一部分，我在hazelcast节点的user-lib文件夹中添加了该jar文件，因此该类可用于每个节点加载数据。该jar文件可用于群集中的每个节点。

现在，当 hazelcast Java客户端，连接到hazelcast群集并尝试从分布式IMap获取数据时，出现以下异常：

Caused by: java.lang.ClassNotFoundException: com.bm.mapstore.OnboardingMapLoader
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at com.hazelcast.nio.ClassLoaderUtil.tryLoadClass(ClassLoaderUtil.java:288)
    at com.hazelcast.nio.ClassLoaderUtil.newInstance0(ClassLoaderUtil.java:212)
    at com.hazelcast.nio.ClassLoaderUtil.newInstance(ClassLoaderUtil.java:193)
    at com.hazelcast.map.impl.mapstore.StoreConstructor.getStoreFromClassOrNull(StoreConstructor.java:81)
    at com.hazelcast.map.impl.mapstore.StoreConstructor.createStore(StoreConstructor.java:46)
    at com.hazelcast.map.impl.mapstore.BasicMapStoreContext.create(BasicMapStoreContext.java:124)
    at com.hazelcast.map.impl.mapstore.MapStoreContextFactory.createMapStoreContext(MapStoreContextFactory.java:48)
    at com.hazelcast.map.impl.MapContainer.<init>(MapContainer.java:155)
    at com.hazelcast.map.impl.MapServiceContextImpl$1.createNew(MapServiceContextImpl.java:194)
    at com.hazelcast.map.impl.MapServiceContextImpl$1.createNew(MapServiceContextImpl.java:190)
    at com.hazelcast.util.ConcurrencyUtil.getOrPutSynchronized(ConcurrencyUtil.java:93)
    at com.hazelcast.map.impl.MapServiceContextImpl.getMapContainer(MapServiceContextImpl.java:278)
    at com.hazelcast.map.impl.operation.MapOperationProviders.getOperationProvider(MapOperationProviders.java:47)
    at com.hazelcast.map.impl.MapServiceContextImpl.getMapOperationProvider(MapServiceContextImpl.java:747)
    at com.hazelcast.client.impl.protocol.task.map.AbstractMapPartitionMessageTask.getMapOperationProvider(AbstractMapPartitionMessageTask.java:36)
    at com.hazelcast.client.impl.protocol.task.map.MapGetMessageTask.prepareOperation(MapGetMessageTask.java:54)
    at com.hazelcast.client.impl.protocol.task.AbstractPartitionMessageTask.processMessage(AbstractPartitionMessageTask.java:62)
    at com.hazelcast.client.impl.protocol.task.AbstractMessageTask.initializeAndProcessMessage(AbstractMessageTask.java:123)
    at com.hazelcast.client.impl.protocol.task.AbstractMessageTask.doRun(AbstractMessageTask.java:111)
    at com.hazelcast.client.impl.protocol.task.AbstractMessageTask.run(AbstractMessageTask.java:101)
    at com.hazelcast.spi.impl.operationservice.impl.OperationRunnerImpl.run(OperationRunnerImpl.java:161)
    at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.process(OperationThread.java:159)
    at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.process(OperationThread.java:127)
    at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.run(OperationThread.java:110)
Apr 19, 2019 1:51:08 PM com.hazelcast.client.connection.ClientConnectionManager

Hazelcast Java客户端代码：

import java.util.Map;

import com.hazelcast.client.HazelcastClient;
import com.hazelcast.client.config.ClientConfig;
import com.hazelcast.core.HazelcastInstance;

public class AppTest {

    public static void main(String[] args) {

        ClientConfig config = new ClientConfig();
        String[] addresses = { "localhost:5701", "localhost:5702" };
        config.getNetworkConfig().addAddress(addresses);

        HazelcastInstance hazelcastInstance = HazelcastClient.newHazelcastClient(config);

          Map<String, Onboarding>  imap = hazelcastInstance
                .getMap("testmap");
        System.out.println(imap.get("6001"));

        hazelcastInstance.shutdown();
    }

}

Maploader源代码：

  package com.bm.mapstore;

    import java.io.Serializable;
    import java.math.BigInteger;
    import java.util.Arrays;
    import java.util.Collection;
    import java.util.HashMap;
    import java.util.HashSet;
    import java.util.Map;
    import java.util.Set;

    import org.bson.Document;
    import org.bson.codecs.configuration.CodecProvider;
    import org.bson.codecs.configuration.CodecRegistries;
    import org.bson.codecs.configuration.CodecRegistry;
    import org.bson.codecs.pojo.Convention;
    import org.bson.codecs.pojo.Conventions;
    import org.bson.codecs.pojo.PojoCodecProvider;

    import com.bm.entity.Onboarding;
    import com.hazelcast.core.MapLoader;
    import com.mongodb.BasicDBObject;
    import com.mongodb.MongoClient;
    import com.mongodb.MongoClientURI;
    import com.mongodb.client.FindIterable;
    import com.mongodb.client.MongoCollection;
    import com.mongodb.client.MongoCursor;
    import com.mongodb.client.MongoDatabase;

    public class OnboardingMapLoader implements MapLoader<String, Onboarding>, Serializable {
        private static final long serialVersionUID = 1L;
        private MongoClient mongoClient;
        private MongoDatabase db;
        private MongoCollection collection;
        private String uri = "mongodb://localhost:27017/demodb";

        public MongoClient getMongoClient() {
            return this.mongoClient;
        }

        public void setMongoClient(MongoClient mongoClient) {
            this.mongoClient = mongoClient;
        }

        public MongoDatabase getDb() {
            return this.db;
        }

        public void setDb(MongoDatabase db) {
            this.db = db;
        }

        public OnboardingMapLoader() {
            CodecRegistry pojoCodecRegistry = CodecRegistries
                    .fromRegistries(new CodecRegistry[] { MongoClient.getDefaultCodecRegistry(),
                            CodecRegistries.fromProviders(new CodecProvider[] { PojoCodecProvider.builder()
                                    .conventions(Arrays.asList(new Convention[] { Conventions.ANNOTATION_CONVENTION }))
                                    .automatic(true).build() }) });

            this.mongoClient = new MongoClient(new MongoClientURI(uri));
            this.db = this.mongoClient.getDatabase("dbvadd1").withCodecRegistry(pojoCodecRegistry);
            this.collection = this.db.getCollection("onboarding");
        }

        @Override
        public Onboarding load(String key) {
            System.out.println("---------------inside load key is -----------------" + key);
            BasicDBObject searchQuery = new BasicDBObject();
            searchQuery.put("_id", key);
            Document doc = (Document) collection.find(searchQuery).first();
            Onboarding onboarding = new Onboarding();
            onboarding.setSvcInvkrId(doc.getString("_id"));
            onboarding.setAllowMultiple(doc.getString("allowMultiple"));
            onboarding.setBid(new BigInteger(doc.getString("bid")));
            System.out.println("---------------inside load onboarding is -----------------" + onboarding);
            return onboarding;
        }

        @Override
        public Map<String, Onboarding> loadAll(Collection<String> keys) {
            Map<String, Onboarding> result = new HashMap();
            FindIterable<Document> documents = this.collection.find();
            for (MongoCursor localMongoCursor = documents.iterator(); localMongoCursor.hasNext();) {
                Document doc = (Document) localMongoCursor.next();
                Onboarding onboarding = new Onboarding();
                onboarding.setSvcInvkrId(doc.getString("_id"));
                onboarding.setAllowMultiple(doc.getString("allowMultiple"));
                onboarding.setBid(new BigInteger(doc.getString("bid")));
                result.put(onboarding.getSvcInvkrId(), onboarding);
            }
            System.out.println("---------------inside loadAll result is-----------------" + result);
            return result;
        }

        public Set<String> loadAllKeys() {
            return new HashSet<String>(Arrays.asList("6001", "6002"));
        }

    }

请帮助解决客户端代码中未找到的类异常。

Answer 1

您是否已验证OnboardingMapLoader.class确实位于./user-lib目录中的jar文件中？

Answer 2

此异常从服务器传播到客户端，因此首先您应该在服务器端看到日志。似乎根本找不到该类，或者服务器无法加载它。您有机会看到一个更早的异常或导致您异常的异常。

如果什么也没看到，并且集群端有一段Java代码，请尝试自己实例化OnboardingMapLoader（新的Onboarding ...），看看是否没有相同的异常。

此外，如果您以编程方式配置HazelcastInstance，则可以通过在服务器上调用hzInstance.getMap来强制加载地图，因此不必在客户端中进行操作（不过，必须对EAGER使用initialLoadMode）。

在hazelcast中的服务器级别配置的MapLoader的java.lang.ClassNotFoundException

2 个答案: