I have few existing test cases scripted with HTTP client. Trying to switch to Karate framework, only hurdle is migrating existing test case. Is there any way to migrate or any way to import from swagger or any alternative?
First let me provide a disclaimer that there is no "short cut" to test-automation. You get the best results when you write tests by hand.
That said, you can evaluate Karate Studio (commercial): https://www.karatelabs.io/studio
We are working on adding import from Postman collections and Swagger etc. to the VS Code and IntelliJ plugins. This will be available by the end of the year.