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今天就跟大家聊聊有关如何使用Springboot线程池,可能很多人都不太了解,为了让大家更加了解,小编给大家总结了以下内容,希望大家根据这篇文章可以有所收获。
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创建springboot工程
用IntelliJ IDEA创建一个springboot的web工程threadpooldemoserver,pom.xml内容如下:
4.0.0 com.vincent threadpooldemoserver 1.0-SNAPSHOT UTF-8 1.8 1.8 org.springframework.boot spring-boot-dependencies 2.1.4.RELEASE import pom org.springframework.boot spring-boot-starter-web org.projectlombok lombok 1.18.6 org.springframework.boot spring-boot-maven-plugin 2.1.4.RELEASE cn.ac.iie.App repackage org.apache.maven.plugins maven-surefire-plugin true
创建一个service层的接口AsyncService,如下:
public interface AsyncService { /** * 执行异步任务 */ void executeAsync(); }
对应的AsyncServiceImpl,实现如下:
@Service @Slf4j public class AsyncServiceImpl implements AsyncService { @Override public void executeAsync() { log.info("start executeAsync"); try{ Thread.sleep(1000); }catch(Exception e){ e.printStackTrace(); } log.info("end executeAsync"); } }
这个方法做的事情很简单:sleep了一秒钟;
创建一个controller为Hello,里面定义一个http接口,做的事情是调用Service层的服务,如下:
@RestController @Slf4j public class Hello { @Autowired private AsyncService asyncService; @RequestMapping("/") public String submit() { log.info("start submit"); //调用service层的任务 asyncService.executeAsync(); log.info("end submit"); return "success"; } }
至此,我们已经做好了一个http请求的服务,里面做的事情其实是同步的,接下来我们就开始配置springboot的线程池服务,将service层做的事情都提交到线程池中去处理;
创建一个配置类ExecutorConfig,用来定义如何创建一个ThreadPoolTaskExecutor,要使用@Configuration和@EnableAsync这两个注解,表示这是个配置类,并且是线程池的配置类,如下所示:
@Configuration @EnableAsync @Slf4j public class ExecutorConfig { @Bean public Executor asyncServiceExecutor() { log.info("start asyncServiceExecutor"); ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor(); //配置核心线程数 executor.setCorePoolSize(5); //配置最大线程数 executor.setMaxPoolSize(5); //配置队列大小 executor.setQueueCapacity(99999); //配置线程池中的线程的名称前缀 executor.setThreadNamePrefix("async-service-"); // rejection-policy:当pool已经达到max size的时候,如何处理新任务 // CALLER_RUNS:不在新线程中执行任务,而是有调用者所在的线程来执行 executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy()); //执行初始化 executor.initialize(); return executor; } }
注意,上面的方法名称为asyncServiceExecutor,稍后马上用到;
打开AsyncServiceImpl.java,在executeAsync方法上增加注解@Async(“asyncServiceExecutor”),asyncServiceExecutor是前面ExecutorConfig.java中的方法名,表明executeAsync方法进入的线程池是asyncServiceExecutor方法创建的,如下:
@Service @Slf4j public class AsyncServiceImpl implements AsyncService { @Override @Async("asyncServiceExecutor") public void executeAsync() { log.info("start executeAsync"); try{ Thread.sleep(1000); }catch(Exception e){ e.printStackTrace(); } log.info("end executeAsync"); } }
将这个springboot运行起来(pom.xml所在文件夹下执行mvn spring-boot:run);
在浏览器输入:http://localhost:8080;
在浏览器用F5按钮快速多刷新几次;
在springboot的控制台看见日志如下:
2019-08-12 15:23:00.320 INFO 5848 --- [nio-8080-exec-2] cn.ac.iie.controller.Hello : start submit 2019-08-12 15:23:00.327 INFO 5848 --- [nio-8080-exec-2] cn.ac.iie.controller.Hello : end submit 2019-08-12 15:23:00.327 INFO 5848 --- [async-service-1] cn.ac.iie.service.impl.AsyncServiceImpl : start executeAsync 2019-08-12 15:23:01.329 INFO 5848 --- [async-service-1] cn.ac.iie.service.impl.AsyncServiceImpl : end executeAsync 2019-08-12 15:24:17.449 INFO 5848 --- [nio-8080-exec-5] cn.ac.iie.controller.Hello : start submit 2019-08-12 15:24:17.450 INFO 5848 --- [nio-8080-exec-5] cn.ac.iie.controller.Hello : end submit 2019-08-12 15:24:17.450 INFO 5848 --- [async-service-2] cn.ac.iie.service.impl.AsyncServiceImpl : start executeAsync 2019-08-12 15:24:18.125 INFO 5848 --- [nio-8080-exec-6] cn.ac.iie.controller.Hello : start submit 2019-08-12 15:24:18.126 INFO 5848 --- [nio-8080-exec-6] cn.ac.iie.controller.Hello : end submit 2019-08-12 15:24:18.128 INFO 5848 --- [async-service-3] cn.ac.iie.service.impl.AsyncServiceImpl : start executeAsync 2019-08-12 15:24:18.451 INFO 5848 --- [async-service-2] cn.ac.iie.service.impl.AsyncServiceImpl : end executeAsync 2019-08-12 15:24:18.685 INFO 5848 --- [nio-8080-exec-7] cn.ac.iie.controller.Hello : start submit 2019-08-12 15:24:18.688 INFO 5848 --- [nio-8080-exec-7] cn.ac.iie.controller.Hello : end submit 2019-08-12 15:24:18.703 INFO 5848 --- [async-service-4] cn.ac.iie.service.impl.AsyncServiceImpl : start executeAsync 2019-08-12 15:24:19.130 INFO 5848 --- [async-service-3] cn.ac.iie.service.impl.AsyncServiceImpl : end executeAsync 2019-08-12 15:24:19.704 INFO 5848 --- [async-service-4] cn.ac.iie.service.impl.AsyncServiceImpl : end executeAsync
如上日志所示,我们可以看到controller的执行线程是"nio-8080-exec-5",这是tomcat的执行线程,而service层的日志显示线程名为“async-service-1”,显然已经在我们配置的线程池中执行了,并且每次请求中,controller的起始和结束日志都是连续打印的,表明每次请求都快速响应了,而耗时的操作都留给线程池中的线程去异步执行;
虽然我们已经用上了线程池,但是还不清楚线程池当时的情况,有多少线程在执行,多少在队列中等待呢?这里我创建了一个ThreadPoolTaskExecutor的子类,在每次提交线程的时候都会将当前线程池的运行状况打印出来,代码如下:
@Slf4j public class VisiableThreadPoolTaskExecutor extends ThreadPoolTaskExecutor { private void showThreadPoolInfo(String prefix){ ThreadPoolExecutor threadPoolExecutor = getThreadPoolExecutor(); if(null==threadPoolExecutor){ return; } log.info("{}, {},taskCount [{}], completedTaskCount [{}], activeCount [{}], queueSize [{}]", this.getThreadNamePrefix(), prefix, threadPoolExecutor.getTaskCount(), threadPoolExecutor.getCompletedTaskCount(), threadPoolExecutor.getActiveCount(), threadPoolExecutor.getQueue().size()); } @Override public void execute(Runnable task) { showThreadPoolInfo("1. do execute"); super.execute(task); } @Override public void execute(Runnable task, long startTimeout) { showThreadPoolInfo("2. do execute"); super.execute(task, startTimeout); } @Override public Future> submit(Runnable task) { showThreadPoolInfo("1. do submit"); return super.submit(task); } @Override publicFuture submit(Callable task) { showThreadPoolInfo("2. do submit"); return super.submit(task); } @Override public ListenableFuture> submitListenable(Runnable task) { showThreadPoolInfo("1. do submitListenable"); return super.submitListenable(task); } @Override public ListenableFuture submitListenable(Callable task) { showThreadPoolInfo("2. do submitListenable"); return super.submitListenable(task); } }
如上所示,showThreadPoolInfo方法中将任务总数、已完成数、活跃线程数,队列大小都打印出来了,然后Override了父类的execute、submit等方法,在里面调用showThreadPoolInfo方法,这样每次有任务被提交到线程池的时候,都会将当前线程池的基本情况打印到日志中;
修改ExecutorConfig.java的asyncServiceExecutor方法,将ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor()改为ThreadPoolTaskExecutor executor = new VisiableThreadPoolTaskExecutor(),如下所示:
@Bean public Executor asyncServiceExecutor() { log.info("start asyncServiceExecutor"); ThreadPoolTaskExecutor executor = new VisiableThreadPoolTaskExecutor(); //配置核心线程数 executor.setCorePoolSize(5); //配置最大线程数 executor.setMaxPoolSize(5); //配置队列大小 executor.setQueueCapacity(99999); //配置线程池中的线程的名称前缀 executor.setThreadNamePrefix("async-service-"); // rejection-policy:当pool已经达到max size的时候,如何处理新任务 // CALLER_RUNS:不在新线程中执行任务,而是有调用者所在的线程来执行 executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy()); //执行初始化 executor.initialize(); return executor; }
修改hello.java,方便查看线程池结果:
@RequestMapping("/") public Object submit() { log.info("start submit"); //调用service层的任务 asyncService.executeAsync(); log.info("end submit"); JSONObject jsonObject = new JSONObject(); ThreadPoolExecutor threadPoolExecutor = visiableThreadPoolTaskExecutor.getThreadPoolExecutor(); jsonObject.put("ThreadNamePrefix", visiableThreadPoolTaskExecutor.getThreadNamePrefix()); jsonObject.put("TaskCount", threadPoolExecutor.getTaskCount()); jsonObject.put("completedTaskCount", threadPoolExecutor.getCompletedTaskCount()); jsonObject.put("activeCount", threadPoolExecutor.getActiveCount()); jsonObject.put("queueSize", threadPoolExecutor.getQueue().size()); return jsonObject; }
再次启动该工程,再浏览器反复刷新http://localhost:8080,看到的日志如下:
{ "activeCount": 2, "queueSize": 1, "TaskCount": 26, "completedTaskCount": 23, "ThreadNamePrefix": "async-service-" }
看完上述内容,你们对如何使用Springboot线程池有进一步的了解吗?如果还想了解更多知识或者相关内容,请关注创新互联行业资讯频道,感谢大家的支持。