我试图运行Kafka流应用程序，并且当kafka流启动时我遇到了以下异常。
这是我在Kafka 0.10.1
上使用的配置final Map<String, String> properties = new HashMap<>();
properties.put(StreamsConfig.APPLICATION_ID_CONFIG, "some app id");
properties.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
properties.put(StreamsConfig.CLIENT_ID_CONFIG, "some app id");
properties.put(StreamsConfig.ZOOKEEPER_CONNECT_CONFIG, "localhost:2181");
properties.put(StreamsConfig.KEY_SERDE_CLASS_CONFIG, "org.apache.kafka.common.serialization.Serdes$StringSerde");
properties.put(StreamsConfig.VALUE_SERDE_CLASS_CONFIG, "org.apache.kafka.common.serialization.Serdes$StringSerde");
我得到的例外。
Exception in thread "StreamThread-1" org.apache.kafka.streams.errors.StreamsException: stream-thread [StreamThread-1] Failed to rebalance
at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:410)
at org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:242)
Caused by: java.lang.NullPointerException
at java.io.File.<init>(File.java:360)
at org.apache.kafka.streams.state.internals.RocksDBStore.openDB(RocksDBStore.java:157)
at org.apache.kafka.streams.state.internals.RocksDBStore.init(RocksDBStore.java:163)
at org.apache.kafka.streams.state.internals.MeteredKeyValueStore.init(MeteredKeyValueStore.java:85)
at org.apache.kafka.streams.state.internals.CachingKeyValueStore.init(CachingKeyValueStore.java:62)
at org.apache.kafka.streams.processor.internals.AbstractTask.initializeStateStores(AbstractTask.java:81)
at org.apache.kafka.streams.processor.internals.StreamTask.<init>(StreamTask.java:120)
at org.apache.kafka.streams.processor.internals.StreamThread.createStreamTask(StreamThread.java:633)
at org.apache.kafka.streams.processor.internals.StreamThread.addStreamTasks(StreamThread.java:660)
at org.apache.kafka.streams.processor.internals.StreamThread.access$100(StreamThread.java:69)
at org.apache.kafka.streams.processor.internals.StreamThread$1.onPartitionsAssigned(StreamThread.java:124)
at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator.onJoinComplete(ConsumerCoordinator.java:228)
at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.joinGroupIfNeeded(AbstractCoordinator.java:313)
at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.ensureActiveGroup(AbstractCoordinator.java:277)
at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator.poll(ConsumerCoordinator.java:259)
at org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:1013)
at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:979)
at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:407)
... 1 more
似乎我需要设置state.dir，但这似乎不起作用。默认情况下，在Kafka 0.10.1上，它已默认为/tmp/kafka-streams。有人有什么想法吗？