问题描述
我想使用Java中的并发性向在线API发出请求，下载并解析响应文档，然后将结果数据加载到数据库中.
I want to use concurrency in Java to make requests to an online API, download and parse the response documents, and load the resulting data into a database.
在每个线程中请求，解析和加载一个线程池是否是标准做法?换句话说，只有一个类实现Runnable.或者说，拥有三个不同的线程池，效率更高，第一个线程池发出请求并将其推入队列，第二个线程池从第一个队列中轮询，解析并推入解析的数据到第二个队列，最后是第三个池，轮询第二个队列中的数据并加载到数据库中?在这种情况下，我将编写三个实现Runnable的不同类.
Is it standard to have one pool of threads in which each thread requests, parses, and loads? In other words, only one class implements Runnable. Or is it more efficient to have, say, three different pools of threads, with the first pool of threads making the requests and pushing them to a queue, the second pool of threads polling from the first queue, parsing, and pushing the parsed data to a second queue, and finally the third pool polling the data from the second queue and loading into the database? In this case, I'd write three different classes that implement Runnable.
推荐答案
您必须考虑处理的哪些部分将从并行性中受益.在线API通信很可能是候选方法，因为将涉及套接字和网络等待.与DB交互也是如此.如果有多个 可用 CPU内核，多线程分析可能只会提高性能.
You have to consider which parts of the processing will benefit from parallelism. The online API communication will most likely be a candidate, since there will be sockets and network waits involved. Likewise with the DB interaction. Multithreaded parsing will probably only improve performance if there are multiple available CPU cores.
将整个过程分为3个单独的类肯定会增加凝聚力，这意味着每个类的职责都会减少，这是一件好事.另一方面，将每个这些类设置为Runnable并具有多个队列将增加应用程序的复杂性(可能不必要).
Splitting the entire process into 3 separate classes will definitely increase the cohesion, meaning each class will have less responsibilities, which is a good thing. On the other hand, making each of these classes a Runnable and having several queues will increase the complexity (possibly unecessarily) of the application.
我建议制作3个单独的类，但不要将它们设为Runnable.然后将contains和orchestrates划分为3个类的Runnable，即一个单线程池.如果您发现这样做似乎不够快(并且经过了一些性能分析)，请尝试将可运行对象分成2个线程池:下载和解析以及db访问.
I would suggest making 3 separate classes, but dont make them Runnable. Then make a Runnable that contains and orchestrates the 3 classes, that is one single thread pool. If you see that this doesnt seem to be fast enough (and after some profiling), try splitting the runnable into 2 thread pools: a download and parse, and a db access.
重点是，从简单开始，并根据需要增加复杂性.
The point being, start simple and add complexity as needed.
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