Hazelcast IExecutorService序列化异常问题求助

方案1：将内部类改为静态内部类 #

非静态内部类会隐式持有外部类的实例引用，序列化内部类时会触发外部类的序列化操作。将内部类改为静态后，不再持有外部类引用，仅需自身实现Serializable即可完成序列化。

修改后的代码示例：

public class CacheEventHandleServiceImpl {
    private HazelcastInstance myHazelcastInstance = Hazelcast.newHazelcastInstance();
    private IExecutorService myExecutorService = myHazelcastInstance.getExecutorService("exec");
    private DataTransferModel res;
    private static final Logger log = LoggerFactory.getLogger(CacheEventHandleServiceImpl.class);

    @Override
    public void newEntryCacheHandle(DataTransferModel dataTransferModel, boolean flag) {
        res = dataTransferModel;
        log.info("HANDLING ENTRY CACHE");
        myExecutorService.execute(new MyOtherRunnable());
    }

    // 改为静态内部类
    private static class MyOtherRunnable implements Runnable, Serializable {
        @Override
        public void run() {
            Logger log = LoggerFactory.getLogger(CacheEventHandleServiceImpl.class);
            log.info("MY OTHER RUNNABLE!!!!!!!!!");
        }
    }
}

注意：静态内部类无法直接访问外部类的非静态成员，若需要使用外部类资源，可通过构造参数传递或使用静态成员。

方案2：让外部类实现Serializable接口 #

如果必须保留非静态内部类结构，可让外部类实现Serializable接口，并使用transient修饰不需要序列化的成员（如Hazelcast实例这类无法/无需序列化的对象）。

修改后的代码示例：

// 外部类实现Serializable接口
public class CacheEventHandleServiceImpl implements Serializable {
    // 用transient修饰无需序列化的成员
    private transient HazelcastInstance myHazelcastInstance = Hazelcast.newHazelcastInstance();
    private transient IExecutorService myExecutorService = myHazelcastInstance.getExecutorService("exec");
    private DataTransferModel res;
    private static final Logger log = LoggerFactory.getLogger(CacheEventHandleServiceImpl.class);

    @Override
    public void newEntryCacheHandle(DataTransferModel dataTransferModel, boolean flag) {
        res = dataTransferModel;
        log.info("HANDLING ENTRY CACHE");
        myExecutorService.execute(new MyOtherRunnable());
    }

    class MyOtherRunnable implements Runnable, Serializable {
        @Override
        public void run() {
            log.info("MY OTHER RUNNABLE!!!!!!!!!");
        }
    }
}

错误根源解析 #

Java非静态内部类会隐式持有外部类的实例引用，当Hazelcast通过IExecutorService分发MyOtherRunnable时，需要序列化该对象，进而触发外部类CacheEventHandleServiceImpl的序列化。由于外部类未实现Serializable接口，最终抛出NotSerializableException。

内容的提问来源于stack exchange，提问作者Đinh Tuấn Anh