SpringBoot 构建大模型后端文本对话服务
这里以阿里大模型Qwen为例
首先来到Qwen API官网介绍链接https://bailian.console.aliyun.com/?tab=model#/model-market/detail/qwen3?modelGroup=qwen3
一、创建并保存API KEY
先来到这个API KEY的管理页面https://bailian.console.aliyun.com/?tab=model#/api-key，创建一个API-KEY。然后复制，保存下来。一般格式都是`sk-xxxxxxxxxxxxxxxxxxxxx`这样。
二、查看官网大模型调用SDK示例方法
XML
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dashscope-sdk-java</artifactId>
<!-- 请将 'the-latest-version' 替换为最新版本号：https://mvnrepository.com/artifact/com.alibaba/dashscope-sdk-java -->
<version>the-latest-version</version>
</dependency>这里我选择的是2.20.8版本，导入的依赖是
xml
<!-- https://mvnrepository.com/artifact/com.alibaba/dashscope-sdk-java -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dashscope-sdk-java</artifactId>
<version>2.20.8</version>
</dependency>然后查看对应API的调用代码示例，这里以文本生成-流式输出为例：
Java
import java.util.Arrays;
import java.lang.System;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.alibaba.dashscope.aigc.generation.Generation;
import com.alibaba.dashscope.aigc.generation.GenerationParam;
import com.alibaba.dashscope.aigc.generation.GenerationResult;
import com.alibaba.dashscope.common.Message;
import com.alibaba.dashscope.common.Role;
import com.alibaba.dashscope.exception.ApiException;
import com.alibaba.dashscope.exception.InputRequiredException;
import com.alibaba.dashscope.exception.NoApiKeyException;
import io.reactivex.Flowable;
public class Main {
private static final Logger logger = LoggerFactory.getLogger(Main.class);
private static StringBuilder fullContent = new StringBuilder();
private static void handleGenerationResult(GenerationResult message) {
String content = message.getOutput().getChoices().get(0).getMessage().getContent();
fullContent.append(content);
System.out.println(content);
}
public static void streamCallWithMessage(Generation gen, Message userMsg)
throws NoApiKeyException, ApiException, InputRequiredException {
GenerationParam param = buildGenerationParam(userMsg);
System.out.println("流式输出内容为：");
Flowable<GenerationResult> result = gen.streamCall(param);
result.blockingForEach(message -> handleGenerationResult(message));
System.out.println("完整内容为: " + fullContent.toString());
}
private static GenerationParam buildGenerationParam(Message userMsg) {
return GenerationParam.builder()
// 若没有配置环境变量，请用阿里云百炼API Key将下行替换为：.apiKey("sk-xxx")
.apiKey(System.getenv("DASHSCOPE_API_KEY"))
.model("qwen-plus") // 此处以qwen-plus为例，您可按需更换模型名称。模型列表：https://help.aliyun.com/zh/model-studio/getting-started/models
.messages(Arrays.asList(userMsg))
.resultFormat(GenerationParam.ResultFormat.MESSAGE)
// Qwen3模型通过enable_thinking参数控制思考过程（开源版默认True，商业版默认False）
// 使用Qwen3开源版模型时，若未启用流式输出，请将下行取消注释，否则会报错
//.enableThinking(false)
.incrementalOutput(true)
.build();
}
public static void main(String[] args) {
try {
Generation gen = new Generation();
Message userMsg = Message.builder().role(Role.USER.getValue()).content("你是谁？").build();
streamCallWithMessage(gen, userMsg);
} catch (ApiException | NoApiKeyException | InputRequiredException e) {
logger.error("An exception occurred: {}", e.getMessage());
}
System.exit(0);
}
}三、写Controller和对应的Service
对应的Service类
import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONObject;
import com.baidu.streamapi.config.SpringContextHolder;
import com.baidu.streamapi.utils.ProxySetting;
import org.springframework.http.*;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RequestCallback;
import org.springframework.web.client.ResponseExtractor;
import org.springframework.web.client.RestTemplate;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.nio.charset.StandardCharsets;
import java.util.Collections;
import java.util.function.Consumer;
import com.alibaba.fastjson2.JSONArray;
import org.springframework.web.util.DefaultUriBuilderFactory;
@Service
public class QwenService {
// 替换为你的通义千问 API Key
private static final String QWEN_API_KEY = "sk-xxxxxxxxxx";
private static final String QWEN_API_URL = "https://dashscope.aliyuncs.com/api/v1/services/aigc/text-generation/generation";
private final RestTemplate restTemplate = new RestTemplate();
public void streamChatCompletions(String prompt, Consumer<String> onChunk, Runnable onComplete, Consumer<Exception> onError) {
try {
System.out.println("准备请求通义千问，prompt=" + prompt);
JSONObject body = new JSONObject();
body.put("model", "qwen-turbo"); // 可选模型名
body.put("input", new JSONObject().fluentPut("prompt", prompt));
body.put("parameters", new JSONObject().fluentPut("result_format", "message"));
body.put("stream", true);
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
headers.set("Authorization", "Bearer " + QWEN_API_KEY);
headers.setAccept(Collections.singletonList(MediaType.valueOf("text/event-stream")));
HttpEntity<String> requestEntity = new HttpEntity<>(body.toJSONString(), headers);
RequestCallback requestCallback = restTemplate.httpEntityCallback(requestEntity, String.class);
ResponseExtractor<Void> responseExtractor = response -> {
System.out.println("已收到通义千问响应，开始读取流...");
try (BufferedReader reader = new BufferedReader(new InputStreamReader(response.getBody(), StandardCharsets.UTF_8))) {
String line;
while ((line = reader.readLine()) != null) {
System.out.println("收到一行: " + line);
if (line.startsWith("data:")) {
// 去掉 "data:" 前缀
String jsonStr = line.substring(line.indexOf(":") + 1);
System.out.println("===>data is: " + jsonStr);
onChunk.accept(jsonStr);
}
}
System.out.println("流读取完毕，调用onComplete");
// onChunk.accept("[DONE]");
onComplete.run();
} catch (Exception e) {
System.out.println("流处理异常: " + e.getMessage());
onChunk.accept("error: " + e.getMessage());
onComplete.run();
}
return null;
};
try {
System.out.println("即将发起HTTP请求到通义千问...");
restTemplate.execute(QWEN_API_URL, HttpMethod.POST, requestCallback, responseExtractor);
System.out.println("HTTP请求已发起");
} catch (Exception e) {
System.out.println("HTTP请求异常: " + e.getMessage());
onChunk.accept("error: " + e.getMessage());
onComplete.run();
}
} catch (Exception e) {
System.out.println("主流程异常: " + e.getMessage());
onError.accept(e);
}
}
}对应的Controller类
Java
package com.baidu.streamapi.demos.web;
import org.springframework.beans.factory.annotation.Autowired;
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 org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
import javax.servlet.http.HttpServletResponse;
@RestController
public class StreamController {
@Autowired
private QwenService qwenService;
@GetMapping(value = "/api/qwen/stream", produces = "text/event-stream;charset=UTF-8")
public SseEmitter qwenStream(@RequestParam String prompt, HttpServletResponse response) {
System.out.println("prompt: " + prompt);
// 直接设置响应头，优先级高于 @GetMapping 的 produces 参数
response.setContentType("text/event-stream; charset=UTF-8");
response.setCharacterEncoding("UTF-8");
SseEmitter emitter = new SseEmitter(0L); // 不超时
qwenService.streamChatCompletions(
prompt,
chunk -> {
try {
System.out.println("====>qwenStream send chunk start");
// 明确指定SSE格式，确保每条消息以data: ...\n\n结尾
emitter.send(SseEmitter.event().data(chunk).reconnectTime(3000));
System.out.println("====>qwenStream send chunk end");
} catch (Exception e) {
emitter.completeWithError(e);
}
},
() -> {
emitter.complete();
System.out.println("====> SSE complete");
},
emitter::completeWithError
);
return emitter;
}
} 然后请求/api/qwen/stream这个接口, 会返回多条数据，每一条是在前一条的基础上补充一些信息，通过SSE流式协议返回。
