Spring AI Chat Demo

A minimal Spring Boot + Spring AI application that exposes an HTTP endpoint backed by an OpenAI chat model.

Stack

• Java 21
• Spring Boot 4.0.1
• Spring AI 2.0.0
• Spring Web
• Spring AI OpenAI ChatClient
• Maven

Prerequisites

1. JDK 21 or newer
2. Maven 3.9+
3. An OpenAI API key

Set the API key as an environment variable.

macOS / Linux

export OPENAI_API_KEY="your-api-key"

Windows PowerShell

$env:OPENAI_API_KEY="your-api-key"

Do not commit the API key to Git.

Run

mvn clean spring-boot:run

Test

Open:

http://localhost:8080/ai/ask?question=Explain%20Kafka%20consumer%20groups

Or with curl:

curl "http://localhost:8080/ai/ask?question=Explain%20Kafka%20consumer%20groups"

How it works

HTTP Request
     |
     v
AiController
     |
     v
AiService
     |
     v
Spring AI ChatClient
     |
     v
OpenAI Chat Model
     |
     v
AI Response

The important Spring AI API is:

chatClient
    .prompt()
    .system("...")
    .user(question)
    .call()
    .content();

Next improvements

After this basic example works, the project can be extended with:

• Prompt templates
• Structured output
• Streaming responses
• Embeddings
• Vector database
• RAG
• Tool/function calling
• Conversation memory
• Observability