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如何使用Springboot线程池

发布时间:2021-07-08 16:41:05 来源:亿速云 阅读:246 作者:Leah 栏目:大数据

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。

 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.vincent</groupId>
    <artifactId>threadpooldemoserver</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>2.1.4.RELEASE</version>
                <scope>import</scope>
                <type>pom</type>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.6</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.1.4.RELEASE</version>
                <configuration>
                    <mainClass>cn.ac.iie.App</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </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
@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
@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;

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
@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;

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:

@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");
    }
}

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:

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;

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:

@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
    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() {
        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,请关注亿速云行业资讯频道,感谢大家的支持。

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