主要依赖

<!--spring-boot父工程-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.2.RELEASE</version>
    </parent>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
	<groupId>com.squareup.okhttp3</groupId>
	<artifactId>okhttp</artifactId>
	<version>4.2.0</version>
</dependency>
<dependency>
	<groupId>com.squareup.okhttp3</groupId>
	<artifactId>okhttp-sse</artifactId>
	<version>4.2.0</version>
</dependency>

服务

package cn;

import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;

import java.io.IOException;
import java.util.Map;

@RestController
public class SseController {
    @PostMapping(value = "/sse", produces = {MediaType.TEXT_EVENT_STREAM_VALUE})
    public SseEmitter handleSse(@RequestBody Map<String, Object> data) {
        System.out.println(data);
        SseEmitter emitter = new SseEmitter();
        // 模拟一个长时间运行的任务，每秒发送一个事件
        new Thread(() -> {
            for (int i = 0; i < 5; i++) {
                System.out.println("开始响应 " + i);
                try {
                    emitter.send(System.currentTimeMillis());
                } catch (IOException e) {
                    // 如果客户端断开连接，我们需要关闭emitter
                    emitter.completeWithError(e);
                }
            }
            emitter.complete();


        }).start();
        return emitter;
    }
}

请求

package cn.demo;

import cn.hutool.json.JSONUtil;
import okhttp3.*;
import okhttp3.sse.EventSource;
import okhttp3.sse.EventSourceListener;
import okhttp3.sse.EventSources;

import java.util.Arrays;
import java.util.HashMap;

public class Test_1 {
    public static void main(String[] args) throws Exception {
        OkHttpClient client = new OkHttpClient.Builder().build();

        EventSource.Factory factory = EventSources.createFactory(client);
        // 请求体
        HashMap<String, Object> map = new HashMap<>();
        map.put("prompt", "哈喽，你好");
        map.put("history", Arrays.asList());
        map.put("temperature", 0.9);
        map.put("top_p", 0.7);
        map.put("max_new_tokens", 4096);
        String json = JSONUtil.toJsonStr(map);
        RequestBody body = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), json);
        // 请求对象
        Request request = new Request.Builder()
                .url("http://localhost:8080/sse")
                .post(body)
                .build();

        // 自定义监听器
        EventSourceListener eventSourceListener = new EventSourceListener() {
            @Override
            public void onOpen(EventSource eventSource, Response response) {
                System.out.println("开启");
                super.onOpen(eventSource, response);
            }

            @Override
            public void onEvent(EventSource eventSource, String id, String type, String data) {
                //   接受消息 data
                System.out.println("数据data "+data);
                super.onEvent(eventSource, id, type, data);
            }

            @Override
            public void onClosed(EventSource eventSource) {
                System.out.println("关闭");
                //super.onClosed(eventSource);
            }

            @Override
            public void onFailure(EventSource eventSource, Throwable t, Response response) {
                System.out.println("失败");
                super.onFailure(eventSource, t, response);
            }
        };

        // 创建事件
        EventSource eventSource = factory.newEventSource(request, eventSourceListener);
        //client.dispatcher().executorService().shutdown();

    }

}

说明

请求连接没有立即关闭

当请求完服务后，okhttp本身并不会直接关闭，它有后台挂起的线程。
这里的关闭不是必须的，如果你的应用需要立即关闭连接，释放资源，可以使用最后一行注释的代码。
EventSource eventSource = factory.newEventSource(request, eventSourceListener);这行代码我在window10上循环了50000次，并没有看到明显的资源占用，似乎真的没有必要关闭。

参考官网 https://square.github.io/okhttp/5.x/okhttp/okhttp3/-ok-http-client/index.html