问题描述
当使用Java中的gRPC时，我可以缓存存根（客户端）并在多线程环境中调用它们，还是通道线程安全且可以安全地缓存？
When using gRPC from Java, can I cache stubs (clients) and call them in a multi-threaded environment or are the channels thread-safe and can be safely cached?
如果网络中断，我应该重新创建频道还是足够聪明才能重新连接？我无法在上找到相关信息
If there is a network outage, should I recreate the channel or it is smart enough to reconnect? I couldn't find relevant info on http://www.grpc.io/docs/
谢谢
推荐答案
回答第一个问题：
频道是线程安全的; io.grpc.Channel 标有 @ThreadSafe 注释。存根也是线程安全的，这就是重新配置创建新存根的原因。
Channels are thread safe; io.grpc.Channel is marked with @ThreadSafe annotation. Stubs are also thread-safe, which is why reconfiguration creates a new stub.
回答第二个问题：
如果存在网络中断，则无需重新创建通道。该频道将重新连接指数退避，大致如 doc所述。 Java不会100％符合该算法，因为它不会在以后的重试中增加连接超时。 （不要与实现的指数退避相混淆。）
If there is a network outage, you don't need to recreate the channel. The channel will reconnect with exponential backoff, roughly as described by the connection backoff doc. Java does not 100% conform to that algorithm, because it doesn't increase connection timeouts in later retries. (Not to be confused with the exponential backoff, which is implemented.)
作为一个小小的问题，Netty当前（v0.9.0）的DNS解析发生在正在创建频道，以后不会重新执行。下一个版本不应该有这个问题。
As a small "gotcha," DNS resolution with Netty currently (v0.9.0) happens when the channel is being created, and will not be re-performed later. The next version should not have this issue.
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