在AWS EC2实例中创建HTTP到私有IP的API网关

I'm new to AWS. I have an application say "Apln1" running in the EC2, which is having private and public IP. Also, I have another application say "Apln2" running in another server which will do an HTTP post to the application. Currently, Apln2 is doing POST to the public IP in EC2. I'm new to AWS. I have an application say "Apln