Spring Boot 基于DeferredResult的异步服务

怼烎@ 2021-06-10 20:39 459阅读 0赞

1.  在pom.xml中引入配置

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

1.  建立Service层接口

public interface PiceaService {
        //无返回参数方法
        void task() throws Exception;
        //有返回参数方法
        String task2() throws Exception;
    }

1.  建立Service层实现  
    Service层接口与实现，跟其他正常同步请求一样，没有差别。

@Service
    public class PiceaServiceImpl implements PiceaService {
    
        @Override
        public void task() throws Exception {
            System.out.println("------------------------在看貂蝉，不要打扰--------------");
            Thread.sleep(1000);
        }
    
        @Override
        public String task2 () throws Exception {
            int k = 1;
            System.out.println("------------------------在看鱼，不要打扰--------------");
            Thread.sleep(1000);
            return (String.valueOf(k));
        }
    }

1.  建立Contoller层方法  
    这是重点和核心，首先要定义一个线程池来处理异步的任务。然后就是编写异步的调用方法。

@RestController
    public class PiceaServletContoller {
    
        @Autowired
        private PiceaService piceaService;
    
        @RequestMapping("/deferredresult")
        public DeferredResult<String> deferredResult() throws Exception {
            System.out.println("控制层执行线程:" + Thread.currentThread().getName());
            //超时
            DeferredResult<String> deferredResult = new DeferredResult<String>(10*1000L);
            deferredResult.onTimeout(new Runnable() {
                @Override
                public void run() {
                    System.out.println("异步线程执行超时");
                    deferredResult.setResult("线程执行超时");
                }
            });
            deferredResult.onCompletion(new Runnable() {
                @Override
                public void run() {
                    System.out.println("异步执行完毕");
                }
            });
            FIXED_THREAD_POOL.execute(new Runnable() {
                @Override
                public void run() {
                    System.out.println("异步执行线程:" + Thread.currentThread().getName());
                    try {
                        String str = piceaService.task2();
                        Thread.sleep(1000);
                        deferredResult.setResult("这是【异步】的请求返回: " + str);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            });
            return deferredResult;
        }
    
        /**
         * 线程池
         */
        public static ExecutorService FIXED_THREAD_POOL = Executors.newFixedThreadPool(10);
    }

1.  测试结果及方法  
    浏览器中访问[http://localhost:2001/deferredresult][http_localhost_2001_deferredresult]测试结果。
    
    ![a2f24e44464f50dfc62d522ad16f5d86.png][]

[http_localhost_2001_deferredresult]: https://links.jianshu.com/go?to=http%3A%2F%2Flocalhost%3A2001%2Fdeferredresult
[a2f24e44464f50dfc62d522ad16f5d86.png]: /images/20210527/1d6bc053aa4c4d6b8e9cc830d5cdf5ca.png