非Spring项目中如何向Hazelcast MapStore注入已创建对象

我需要把已创建好的对象注入到Hazelcast MapStore中。Hazelcast官方文档里的示例是通过XML配置传递属性，然后在MapStore的init方法里用这些属性新建对象。但在Vert.x环境下，怎么传递已经构造好的连接对象呢？这是非Spring项目，没法用@SpringAware和Bean注入。

原文档中的XML配置示例：

<hazelcast>
    ...
    <map name="supplements">
        <map-store enabled="true" initial-mode="LAZY">
            <class-name>com.hazelcast.loader.YourMapStoreImplementation</class-name>
            <properties>
                <property name="mongo.url">mongodb://localhost:27017</property>
                <property name="mongo.db">mydb</property>
                <property name="mongo.collection">supplements</property>
            </properties>
        </map-store>
    </map>
    ...
</hazelcast>

在配置中指定数据库属性后，您需要实现MapLoaderLifecycleSupport接口，并在init()方法中使用这些属性，如下所示：

原文档中的MapStore实现示例：

public class YourMapStoreImplementation implements MapStore<String, Supplement>, MapLoaderLifecycleSupport {

    private MongoClient mongoClient;
    private MongoCollection collection;

    public YourMapStoreImplementation() {
    }

    @Override
    public void init(HazelcastInstance hazelcastInstance, Properties properties, String mapName) {
        String mongoUrl = (String) properties.get("mongo.url");
        String dbName = (String) properties.get("mongo.db");
        String collectionName = (String) properties.get("mongo.collection");
        this.mongoClient = new MongoClient(new MongoClientURI(mongoUrl));
        this.collection = mongoClient.getDatabase(dbName).getCollection(collectionName);
    }
}

可行解决方案 #

方法1：通过Hazelcast用户上下文传递对象 #

利用Hazelcast实例的用户上下文存储已构造的对象，在MapStore的init方法中取出使用：

1. 初始化Hazelcast时存入对象：

Vertx vertx = Vertx.vertx();
// 假设已构造好MongoClient连接
MongoClient existingMongoClient = ...;

Config hazelcastConfig = new Config();
// 配置MapStore，仅指定类名即可
MapConfig mapConfig = hazelcastConfig.getMapConfig("supplements");
MapStoreConfig mapStoreConfig = new MapStoreConfig();
mapStoreConfig.setEnabled(true)
               .setInitialMode(MapStoreConfig.InitialMode.LAZY)
               .setClassName("com.hazelcast.loader.YourMapStoreImplementation");
mapConfig.setMapStoreConfig(mapStoreConfig);

// 将已创建的对象放入Hazelcast用户上下文
hazelcastConfig.getUserContext().put("existingMongoClient", existingMongoClient);

HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance(hazelcastConfig);

2. 修改MapStore的init方法获取对象：

public class YourMapStoreImplementation implements MapStore<String, Supplement>, MapLoaderLifecycleSupport {

    private MongoClient mongoClient;
    private MongoCollection collection;

    public YourMapStoreImplementation() {
    }

    @Override
    public void init(HazelcastInstance hazelcastInstance, Properties properties, String mapName) {
        // 从用户上下文取出已构造的MongoClient
        this.mongoClient = (MongoClient) hazelcastInstance.getUserContext().get("existingMongoClient");
        this.collection = mongoClient.getDatabase("mydb").getCollection("supplements");
        // 数据库名、集合名也可存入用户上下文，按需取出
    }

    // 实现MapStore其他方法...
}

方法2：手动实例化MapStore并传入对象 #

跳过配置类名的方式，直接将已初始化的MapStore实例传入Hazelcast配置：

1. 修改MapStore添加带参构造器：

public class YourMapStoreImplementation implements MapStore<String, Supplement> {

    private MongoClient mongoClient;
    private MongoCollection collection;

    // 接收已构造的MongoClient的构造器
    public YourMapStoreImplementation(MongoClient mongoClient) {
        this.mongoClient = mongoClient;
        this.collection = mongoClient.getDatabase("mydb").getCollection("supplements");
    }

    // 实现MapStore其他方法...
}

2. 在Vertx中手动配置：

Vertx vertx = Vertx.vertx();
MongoClient existingMongoClient = ...;

// 手动创建MapStore实例，传入已有的连接对象
YourMapStoreImplementation mapStore = new YourMapStoreImplementation(existingMongoClient);

Config hazelcastConfig = new Config();
MapConfig mapConfig = hazelcastConfig.getMapConfig("supplements");
MapStoreConfig mapStoreConfig = new MapStoreConfig();
mapStoreConfig.setEnabled(true)
               .setInitialMode(MapStoreConfig.InitialMode.LAZY)
               .setImplementation(mapStore); // 直接传入实例而非类名
mapConfig.setMapStoreConfig(mapStoreConfig);

HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance(hazelcastConfig);

注意事项 #

• 方法2需保证MapStore实例是线程安全的，Hazelcast会在多线程环境中调用它。
• 集群部署场景下，方法1需确保每个节点初始化时都存入自己的连接对象（用户上下文为节点本地存储）。

内容的提问来源于stack exchange，提问作者Sergey Afinogenov