springboot线程池的使用和扩展

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;

本文地址:http://blog.csdn.net/boling_cavalry/article/details/79120268

实战环境

  1. windowns10;
  2. jdk1.8;
  3. springboot 1.5.9.RELEASE;
  4. 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:[email protected]:zq2599/blog_demos.git,项目主页:https://github.com/zq2599/blog_demos

这里面有多个工程,本次用到的工程为threadpooldemoserver,如下图红框所示: 
这里写图片描述

实战步骤梳理

本次实战的步骤如下: 
1. 创建springboot工程; 
2. 创建Service层的接口和实现; 
3. 创建controller,开发一个http服务接口,里面会调用service层的服务; 
4. 创建线程池的配置; 
5. 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; 
6. 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>
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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(); }
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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"); } }
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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"; } }
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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; } }
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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"); }
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验证效果

  1. 将这个springboot运行起来(pom.xml所在文件夹下执行mvn spring-boot:run);
  2. 在浏览器输入:http://localhost:8080
  3. 在浏览器用F5按钮快速多刷新几次;
  4. 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
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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); } }
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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; }
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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
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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;

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转载自www.cnblogs.com/pejsidney/p/9001875.html