HttpURLConnection: Is it necessary to call connect()?

问题

Many examples I've seen don't explicitly call connect(). Instead they just use getInputStream() or getResponseCode().

I'm assuming all of these HttpURLConnection methods that require a connection just call connect() themselves?

Are there any cases where connect() must be explicitly called for an HttpURLConnection?

回答1:

No, there are no cases. It's implicitly executed on demand. It's even specified in the documentation. Here's an extract of the URLConnection#connect() javadoc:

Operations that depend on being connected, like getContentLength, will implicitly perform the connection, if necessary.

回答2:

connect() is implied and automatically invoked when needed.

来源：https://stackoverflow.com/questions/2792705/httpurlconnection-is-it-necessary-to-call-connect