深入学习springboot线程池的使用和扩展
前言
我们常用ThreadPoolExecutor提供的线程池服务,springboot框架提供了@Async注解,帮助我们更方便的将业务逻辑提交到线程池中异步执行,今天我们就来实战体验这个线程池服务;
实战环境
- windowns10;
- jdk1.8;
- springboot 1.5.9.RELEASE;
- 开发工具:IntelliJ IDEA;
实战源码
本次实战的源码可以在我的GitHub下载,地址:git@github.com:zq2599/blog_demos.git,项目主页:
这里面有多个工程,本次用到的工程为threadpooldemoserver
实战步骤梳理
本次实战的步骤如下:
- 创建springboot工程;
- 创建Service层的接口和实现;
- 创建controller,开发一个http服务接口,里面会调用service层的服务;
- 创建线程池的配置;
- 将Service层的服务异步化,这样每次调用都会都被提交到线程池异步执行;
- 扩展ThreadPoolTaskExecutor,在提交任务到线程池的时候可以观察到当前线程池的情况;
创建springboot工程
用IntelliJ IDEA创建一个springboot的web工程threadpooldemoserver,pom.xml内容如下:
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.bolingcavalry</groupId> <artifactId>threadpooldemoserver</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>threadpooldemoserver</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.9.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
创建Service层的接口和实现
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 public class AsyncServiceImpl implements AsyncService { private static final Logger logger = LoggerFactory.getLogger(AsyncServiceImpl.class); @Override public void executeAsync() { logger.info("start executeAsync"); try{ Thread.sleep(1000); }catch(Exception e){ e.printStackTrace(); } logger.info("end executeAsync"); } }
这个方法做的事情很简单:sleep了一秒钟;
创建controller
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 public class Hello { private static final Logger logger = LoggerFactory.getLogger(Hello.class); @Autowired private AsyncService asyncService; @RequestMapping("/") public String submit(){ logger.info("start submit"); //调用service层的任务 asyncService.executeAsync(); logger.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;
springboot的线程池配置
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 public class ExecutorConfig { private static final Logger logger = LoggerFactory.getLogger(ExecutorConfig.class); @Bean public Executor asyncServiceExecutor() { logger.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;
将Service层的服务异步化
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:
@Override @Async("asyncServiceExecutor") public void executeAsync() { logger.info("start executeAsync"); try{ Thread.sleep(1000); }catch(Exception e){ e.printStackTrace(); } logger.info("end executeAsync"); }
验证效果
- 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:
2018-01-21 22:43:18.630 INFO 14824 --- [nio-8080-exec-8] c.b.t.controller.Hello : start submit 2018-01-21 22:43:18.630 INFO 14824 --- [nio-8080-exec-8] c.b.t.controller.Hello : end submit 2018-01-21 22:43:18.929 INFO 14824 --- [async-service-1] c.b.t.service.impl.AsyncServiceImpl : end executeAsync 2018-01-21 22:43:18.930 INFO 14824 --- [async-service-1] c.b.t.service.impl.AsyncServiceImpl : start executeAsync 2018-01-21 22:43:19.005 INFO 14824 --- [async-service-2] c.b.t.service.impl.AsyncServiceImpl : end executeAsync 2018-01-21 22:43:19.006 INFO 14824 --- [async-service-2] c.b.t.service.impl.AsyncServiceImpl : start executeAsync 2018-01-21 22:43:19.175 INFO 14824 --- [async-service-3] c.b.t.service.impl.AsyncServiceImpl : end executeAsync 2018-01-21 22:43:19.175 INFO 14824 --- [async-service-3] c.b.t.service.impl.AsyncServiceImpl : start executeAsync 2018-01-21 22:43:19.326 INFO 14824 --- [async-service-4] c.b.t.service.impl.AsyncServiceImpl : end executeAsync 2018-01-21 22:43:19.495 INFO 14824 --- [async-service-5] c.b.t.service.impl.AsyncServiceImpl : end executeAsync 2018-01-21 22:43:19.930 INFO 14824 --- [async-service-1] c.b.t.service.impl.AsyncServiceImpl : end executeAsync 2018-01-21 22:43:20.006 INFO 14824 --- [async-service-2] c.b.t.service.impl.AsyncServiceImpl : end executeAsync 2018-01-21 22:43:20.191 INFO 14824 --- [async-service-3] c.b.t.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-8",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;
扩展ThreadPoolTaskExecutor
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:
public class VisiableThreadPoolTaskExecutor extends ThreadPoolTaskExecutor { private static final Logger logger = LoggerFactory.getLogger(VisiableThreadPoolTaskExecutor.class); private void showThreadPoolInfo(String prefix){ ThreadPoolExecutor threadPoolExecutor = getThreadPoolExecutor(); if(null==threadPoolExecutor){ return; } logger.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 public <T> Future<T> submit(Callable<T> 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 <T> ListenableFuture<T> submitListenable(Callable<T> 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() { logger.info("start asyncServiceExecutor"); //使用VisiableThreadPoolTaskExecutor 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; }
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:
2018-01-21 23:04:56.113 INFO 15580 --- [nio-8080-exec-1] c.b.t.e.VisiableThreadPoolTaskExecutor : async-service-, 2. do submit,taskCount [99], completedTaskCount [85], activeCount [5], queueSize [9] 2018-01-21 23:04:56.113 INFO 15580 --- [nio-8080-exec-1] c.b.t.controller.Hello : end submit 2018-01-21 23:04:56.225 INFO 15580 --- [async-service-1] c.b.t.service.impl.AsyncServiceImpl : end executeAsync 2018-01-21 23:04:56.225 INFO 15580 --- [async-service-1] c.b.t.service.impl.AsyncServiceImpl : start executeAsync 2018-01-21 23:04:56.240 INFO 15580 --- [nio-8080-exec-2] c.b.t.controller.Hello : start submit 2018-01-21 23:04:56.240 INFO 15580 --- [nio-8080-exec-2] c.b.t.e.VisiableThreadPoolTaskExecutor : async-service-, 2. do submit,taskCount [100], completedTaskCount [86], activeCount [5], queueSize [9] 2018-01-21 23:04:56.240 INFO 15580 --- [nio-8080-exec-2] c.b.t.controller.Hello : end submit 2018-01-21 23:04:56.298 INFO 15580 --- [async-service-2] c.b.t.service.impl.AsyncServiceImpl : end executeAsync 2018-01-21 23:04:56.298 INFO 15580 --- [async-service-2] c.b.t.service.impl.AsyncServiceImpl : start executeAsync 2018-01-21 23:04:56.372 INFO 15580 --- [nio-8080-exec-3] c.b.t.controller.Hello : start submit 2018-01-21 23:04:56.373 INFO 15580 --- [nio-8080-exec-3] c.b.t.e.VisiableThreadPoolTaskExecutor : async-service-, 2. do submit,taskCount [101], completedTaskCount [87], activeCount [5], queueSize [9] 2018-01-21 23:04:56.373 INFO 15580 --- [nio-8080-exec-3] c.b.t.controller.Hello : end submit 2018-01-21 23:04:56.444 INFO 15580 --- [async-service-3] c.b.t.service.impl.AsyncServiceImpl : end executeAsync 2018-01-21 23:04:56.445 INFO 15580 --- [async-service-3] c.b.t.service.impl.AsyncServiceImpl : start executeAsync
注意这一行日志:2. do submit,taskCount [101], completedTaskCount [87], activeCount [5], queueSize [9]
这说明提交任务到线程池的时候,调用的是submit(Callable task)这个方法,当前已经提交了101个任务,完成了87个,当前有5个线程在处理任务,还剩9个任务在队列中等待,线程池的基本情况一路了然;
至此,springboot线程池服务的实战就完成了,希望能帮您在工程中快速实现异步服务;
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持亿速云。