通过使用线程和连接，下载是串行，正如我上面所说的。

By using threads and join, downloading is serial, as I said above.

youdao

使用全局连接工厂和线程级别连接缓存。

Using a global connection factory and thread-level connection caching.

youdao

使用全局连接工厂和线程级别连接缓存。

Using a global connection factory and thread-level connection caching.

youdao