springboot中异步接口实现所有方式_20250501

几种异步接口实现demo

package org.dromara.controller.app;// 导入必要的依赖库import cn.dev33.satoken.annotation.SaIgnore;
import lombok.extern.slf4j.Slf4j;
import org.springframework.core.io.Resource;
import org.springframework.core.io.UrlResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.context.request.async.DeferredResult;
import org.springframework.web.context.request.async.WebAsyncTask;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyEmitter;
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
import org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody;import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.util.Map;
import java.util.concurrent.*;/*** 异步接口实现方式大全* 演示Spring Boot中多种异步处理方案：* 1. 响应体发射器（ResponseBodyEmitter）* 2. 服务器发送事件（SSE）* 3. 文件流传输* 4. Callable异步调用* 5. WebAsyncTask* 6. 延迟结果（DeferredResult）*/
@Slf4j // Lombok生成日志对象
@SaIgnore // 忽略权限校验
@RestController // REST控制器
@RequestMapping("testAsync") // 请求路径前缀
public class TestAsyncController {// 创建单线程定时任务线程池private static final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);// 延迟结果存储容器（线程安全）private static final Map<String, DeferredResult<String>> DEFERRED_RESULT_MAP = new ConcurrentHashMap<>();/*** 使用ResponseBodyEmitter实现持续通信* 每2秒向客户端发送时间戳消息*/@GetMapping("/emitter")public ResponseEntity<ResponseBodyEmitter> handle() {// 创建响应发射器ResponseBodyEmitter emitter = new ResponseBodyEmitter();// 定时任务：每2秒发送一次消息scheduler.scheduleAtFixedRate(() -> {try {emitter.send(String.format("timestamp: %d\n", System.currentTimeMillis()), MediaType.TEXT_PLAIN);} catch (IOException e) {throw new RuntimeException(e);}}, 0, 2, TimeUnit.SECONDS); // 初始延迟0s，间隔2s// 设置10秒超时处理// 关闭连接emitter.onTimeout(emitter::complete);return new ResponseEntity<>(emitter, HttpStatus.OK);}/*** 使用SseEmitter实现服务器发送事件(SSE)* 每3秒推送自定义事件消息*/@GetMapping("/sse")public SseEmitter handleSse() {SseEmitter emitter = new SseEmitter();// 定时事件推送（3秒间隔）scheduler.scheduleAtFixedRate(() -> {try {// 构建SSE事件：事件名+数据SseEmitter.SseEventBuilder event = SseEmitter.event().name("sse").data(String.format("timestamp: %d", System.currentTimeMillis()));emitter.send(event);} catch (IOException e) {emitter.completeWithError(e); // 发生异常时关闭连接}}, 0, 3, TimeUnit.SECONDS);// 15秒超时处理// 关闭连接emitter.onTimeout(emitter::complete);return emitter;}/*** 文件流式传输示例* 实现大文件下载（模拟）*/@GetMapping("/stream")public ResponseEntity<StreamingResponseBody> handleStream() throws MalformedURLException {// 创建远程资源对象（演示用URL）Resource resource = new UrlResource("https://blog.csdn.net/lcj_star/");// 流式响应体实现StreamingResponseBody stream = outputStream -> {try (InputStream inputStream = resource.getInputStream()) {byte[] buffer = new byte[1024];int bytesRead;// 分块传输文件内容while ((bytesRead = inputStream.read(buffer)) != -1) {outputStream.write(buffer, 0, bytesRead);}} catch (IOException e) {log.error("文件读取失败: {}", e.getMessage(), e);}};// 构建响应头HttpHeaders headers = new HttpHeaders();headers.setContentType(MediaType.APPLICATION_OCTET_STREAM); // 二进制流类型headers.setContentDispositionFormData("attachment", resource.getFilename()); // 强制下载return ResponseEntity.ok().headers(headers).body(stream);}/*** Callable异步处理示例* 模拟耗时操作后返回结果*/@GetMapping("/callAble")public Callable<String> testCallAble() {return () -> {Thread.sleep(4000); // 模拟4秒耗时return "hello"; // 返回结果};}/*** WebAsyncTask异步处理示例* 支持超时和完成回调*/@GetMapping("/webAsyncTask")public WebAsyncTask<String> webAsyncTask() {// 创建异步任务（超时时间30003ms）WebAsyncTask<String> result = new WebAsyncTask<>(30003, () -> {return "success"; // 任务主体});// 超时回调result.onTimeout(() -> {log.info("timeout callback");return "timeout callback";});// 完成回调result.onCompletion(() -> log.info("finish callback"));return result;}/*** 延迟结果示例* 持有连接等待外部触发结果*/@GetMapping("/deferredResult")public DeferredResult<String> testDeferredResult() {DeferredResult<String> deferredResult = new DeferredResult<>();DEFERRED_RESULT_MAP.put("demo", deferredResult); // 存储实例return deferredResult; // 挂起请求}/*** 触发延迟结果* 外部调用设置结果*/@GetMapping("/setDeferredResult")public String testSetDeferredResult() {DeferredResult<String> deferredResult = DEFERRED_RESULT_MAP.get("demo"); // 获取实例boolean flag = deferredResult.setResult("DeferredResult hello"); // 设置结果if (!flag) {log.info("结果已经被处理，此次操作无效");}return "success";}
}

总结