How to Add Generative AI to Your Spring Boot App with Spring AI

Hands‑On Demo

Step 1: Generate a basic Spring Boot project with your favorite IDE. If you are unfamiliar, follow a Spring Boot quick‑start guide.

Step 2: Open application.properties and configure your OpenAI API key:

spring.ai.openai.api-key=<YOUR_OPENAI_API_KEY>

Step 3: Create OpenAIController.java:

@RestController
@RequestMapping("/api/v1")
public class OpenAIController {
    private final AiClient aiClient;
    public OpenAIController(AiClient aiClient) {
        this.aiClient = aiClient;
    }
}

Step 4: Use the AiClient to return content based on the request:

@GetMapping("/completion")
public String completion(@RequestParam(value = "message") String message) {
    return this.aiClient.generate(message);
}

The simple example works, but real applications usually need a Prompt to obtain more accurate results. For example:

@GetMapping("/completion")
public AiResponse completion(@RequestParam(value = "message") String message) {
    PromptTemplate promptTemplate = new PromptTemplate("translate the given english sentence into french {query}");
    Prompt prompt = promptTemplate.create(Map.of("query", message));
    return this.aiClient.generate(prompt);
}

Here a PromptTemplate creates a template, and a Prompt is built from it using the user input.

The Prompt class holds a list of Message objects; each message represents a part of the prompt. Combining different messages, such as a system prompt and a user prompt, enables more sophisticated interactions with the AI model.

More complex usage can combine a system prompt and a user prompt:

@GetMapping("/completion")
public List<Generation> completion(@RequestParam(value = "message") String message) {
    String systemPrompt = ""
        + "You are a helpful AI assistant that helps people translate given text from english to french.
"
        + "Your name is TranslatePro.
"
        + "You should reply to the user's request with your name and also in the style of a professional.
";
    SystemPromptTemplate systemPromptTemplate = new SystemPromptTemplate(systemPrompt);
    Message systemMessage = systemPromptTemplate.createMessage();

    PromptTemplate promptTemplate = new PromptTemplate("translate the given english sentence into french {query}");
    Message userMessage = promptTemplate.createMessage(Map.of("query", message));

    Prompt prompt = new Prompt(List.of(systemMessage, userMessage));
    return this.aiClient.generate(prompt).getGenerations();
}

After implementing these APIs, start the application and invoke the endpoints with an API testing tool to experience the power of generative AI.