企业级 SpringBoot 教程（二十三）异步方法

﹏ヽ暗。殇╰゛Y 2022-03-08 08:06 280阅读 0赞

创建工程

在pom文件引入相关依赖： Spring Cloud大型企业分布式微服务云架构源码请加一七九一七四三三八零

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
     
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-web</artifactId>
            </dependency>
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-databind</artifactId>
            </dependency>

创建一个接收数据的实体：

@JsonIgnoreProperties(ignoreUnknown=true)
    public class User {
     
        private String name;
        private String blog;
     
        public String getName() {
            return name;
        }
     
        public void setName(String name) {
            this.name = name;
        }
     
        public String getBlog() {
            return blog;
        }
     
        public void setBlog(String blog) {
            this.blog = blog;
        }
     
        @Override
        public String toString() {
            return "User [name=" + name + ", blog=" + blog + "]";
        }
     
    }

创建一个请求的　githib的service:

@Service
    public class GitHubLookupService {
     
        private static final Logger logger = LoggerFactory.getLogger(GitHubLookupService.class);
     
        private final RestTemplate restTemplate;
     
        public GitHubLookupService(RestTemplateBuilder restTemplateBuilder) {
            this.restTemplate = restTemplateBuilder.build();
        }
     
        @Async
        public Future<User> findUser(String user) throws InterruptedException {
            logger.info("Looking up " + user);
            String url = String.format("https://api.github.com/users/%s", user);
            User results = restTemplate.getForObject(url, User.class);
            // Artificial delay of 1s for demonstration purposes
            Thread.sleep(1000L);
            return new AsyncResult<>(results);
        }
     
    }

通过，RestTemplate去请求，另外加上类@Async 表明是一个异步任务。

开启异步任务：

@SpringBootApplication
    @EnableAsync
    public class Application extends AsyncConfigurerSupport {
     
        public static void main(String[] args) {
            SpringApplication.run(Application.class, args);
        }
     
        @Override
        public Executor getAsyncExecutor() {
            ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
            executor.setCorePoolSize(2);
            executor.setMaxPoolSize(2);
            executor.setQueueCapacity(500);
            executor.setThreadNamePrefix("GithubLookup-");
            executor.initialize();
            return executor;
        }
     
    }

通过@EnableAsync开启异步任务；并且配置AsyncConfigurerSupport，比如最大的线程池为2.

测试

测试代码如下：

@Component
    public class AppRunner implements CommandLineRunner {
     
        private static final Logger logger = LoggerFactory.getLogger(AppRunner.class);
     
        private final GitHubLookupService gitHubLookupService;
     
        public AppRunner(GitHubLookupService gitHubLookupService) {
            this.gitHubLookupService = gitHubLookupService;
        }
     
        @Override
        public void run(String... args) throws Exception {
            // Start the clock
            long start = System.currentTimeMillis();
     
            // Kick of multiple, asynchronous lookups
            Future<User> page1 = gitHubLookupService.findUser("PivotalSoftware");
            Future<User> page2 = gitHubLookupService.findUser("CloudFoundry");
            Future<User> page3 = gitHubLookupService.findUser("Spring-Projects");
     
            // Wait until they are all done
            while (!(page1.isDone() && page2.isDone() && page3.isDone())) {
                Thread.sleep(10); //10-millisecond pause between each check
            }
     
            // Print results, including elapsed time
            logger.info("Elapsed time: " + (System.currentTimeMillis() - start));
            logger.info("--> " + page1.get());
            logger.info("--> " + page2.get());
            logger.info("--> " + page3.get());
        }
     
    }

启动程序，控制台会打印：

2017-04-30 13:11:10.351 INFO 1511 — [ GithubLookup-1] com.forezp.service.GitHubLookupService : Looking up PivotalSoftware
    2017-04-30 13:11:10.351 INFO 1511 — [ GithubLookup-2] com.forezp.service.GitHubLookupService : Looking up CloudFoundry
    2017-04-30 13:11:13.144 INFO 1511 — [ GithubLookup-2] com.forezp.service.GitHubLookupService : Looking up Spring-Projects