Spring AI 入门：DeepSeek 集成、角色设定与流式输出

2. 配置文件 (application.yml)

spring:
  ai:
    deepseek:
      api-key: sk-xxxxxxxxx
      base-url: https://api.deepseek.com

3. 基础调用示例

使用 ChatClient 发送用户消息并获取文本响应。

import org.springframework.ai.chat.client.ChatClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/my")
class MyController {
    private final ChatClient chatClient;

    public MyController(ChatClient.Builder chatClientBuilder) {
        this.chatClient = chatClientBuilder.build();
    }

    @GetMapping("/ai")
    public String generation(@RequestParam("message") String message) {
        return this.chatClient.prompt()
                .user(message)
                .call()
                .content();
    }
}

预设系统角色

通过自定义 ChatClient Bean 设置 System Prompt，定义 AI 的身份和行为准则。

import org.springframework.ai.chat.client.ChatClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class Config {
    @Bean
    ChatClient chatClient(ChatClient.Builder builder) {
        return builder.defaultSystem("你现在是斩神神经病院的一个客服，需要为客户解答。我们神经病院的院长叫林七夜，他最擅长的就是精神分裂治疗。").build();
    }
}

流式输出 (SSE)

使用 Flux<String> 实现按 Token 流式返回内容，前端可实时展示。

import org.springframework.ai.chat.client.ChatClient;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import reactor.core.publisher.Flux;

@RestController
public class StreamController {
    private final ChatClient chatClient;

    public StreamController(ChatClient.Builder builder) {
        this.chatClient = builder.build();
    }

    @GetMapping(value = "/stream", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
    public Flux<String> stream(@RequestParam("message") String message) {
        return chatClient.prompt()
                .user(message)
                .stream()
                .content();
    }
}

注意：确保 produces 设置为 MediaType.TEXT_EVENT_STREAM_VALUE 以支持 SSE 协议。

代理配置

若访问外部 API 需经过代理，可在启动类中设置 JVM 属性。

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class ApplicationProxy {
    public static void main(String[] args) {
        // 代理配置
        String proxyHost = "127.0.0.1";
        int proxyPort = 7897;

        System.setProperty("http.proxyHost", proxyHost);
        System.setProperty("http.proxyPort", String.valueOf(proxyPort));
        System.setProperty("https.proxyHost", proxyHost);
        System.setProperty("https.proxyPort", String.valueOf(proxyPort));
        System.setProperty("socksProxyHost", proxyHost);
        System.setProperty("socksProxyPort", String.valueOf(proxyPort));

        SpringApplication.run(ApplicationProxy.class, args);
    }
}