Passing multiple values from Confluence to JIRA via API

[Bill Blinn]

The company I work for is upgrading JIRA to v7.3.6 from v6.3.12 and I'm having trouble finding answers to some questions. Here is my second question:

Currently we use https://JIRA-URL/secure/CreateIssueDetails!init.jspa to post data from a Confluence form to JIRA.

Assuming that this API call hasn't changed in version 7, is there a way to pass multiple values to JIRA fields that accept them? Example: Labels and Components can both have multiple values, but I haven't found a way to pass more than one value via the HTTPS post.

Is this possible or should I stop looking for a capability that doesn't exist?