深入學(xué)習(xí)springboot線程池的使用和擴(kuò)展

更新時(shí)間：2019年06月25日 14:27:07 作者：程序員欣宸

這篇文章主要介紹了深入學(xué)習(xí)springboot線程池的使用和擴(kuò)展，springboot框架提供了@Async注解，幫助我們更方便的將業(yè)務(wù)邏輯提交到線程池中異步執(zhí)行,需要的朋友可以參考下

前言

我們常用ThreadPoolExecutor提供的線程池服務(wù)，springboot框架提供了@Async注解，幫助我們更方便的將業(yè)務(wù)邏輯提交到線程池中異步執(zhí)行，今天我們就來(lái)實(shí)戰(zhàn)體驗(yàn)這個(gè)線程池服務(wù)；

實(shí)戰(zhàn)環(huán)境

windowns10；
jdk1.8；
springboot 1.5.9.RELEASE；
開(kāi)發(fā)工具：IntelliJ IDEA；

實(shí)戰(zhàn)源碼

本次實(shí)戰(zhàn)的源碼可以在我的GitHub下載，地址：git@github.com:zq2599/blog_demos.git，項(xiàng)目主頁(yè)：

這里面有多個(gè)工程，本次用到的工程為threadpooldemoserver

實(shí)戰(zhàn)步驟梳理

本次實(shí)戰(zhàn)的步驟如下：

創(chuàng)建springboot工程；
創(chuàng)建Service層的接口和實(shí)現(xiàn)；
創(chuàng)建controller，開(kāi)發(fā)一個(gè)http服務(wù)接口，里面會(huì)調(diào)用service層的服務(wù)；
創(chuàng)建線程池的配置；
將Service層的服務(wù)異步化，這樣每次調(diào)用都會(huì)都被提交到線程池異步執(zhí)行；
擴(kuò)展ThreadPoolTaskExecutor，在提交任務(wù)到線程池的時(shí)候可以觀察到當(dāng)前線程池的情況；

創(chuàng)建springboot工程

用IntelliJ IDEA創(chuàng)建一個(gè)springboot的web工程threadpooldemoserver，pom.xml內(nèi)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>

創(chuàng)建Service層的接口和實(shí)現(xiàn)

創(chuàng)建一個(gè)service層的接口AsyncService，如下：

public interface AsyncService {
/**
* 執(zhí)行異步任務(wù)
*/
void executeAsync();
}

對(duì)應(yīng)的AsyncServiceImpl，實(shí)現(xiàn)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");
}
}

這個(gè)方法做的事情很簡(jiǎn)單：sleep了一秒鐘；

創(chuàng)建controller

創(chuàng)建一個(gè)controller為Hello，里面定義一個(gè)http接口，做的事情是調(diào)用Service層的服務(wù)，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");
//調(diào)用service層的任務(wù)
asyncService.executeAsync();
logger.info("end submit");
return "success";
}
}

至此，我們已經(jīng)做好了一個(gè)http請(qǐng)求的服務(wù)，里面做的事情其實(shí)是同步的，接下來(lái)我們就開(kāi)始配置springboot的線程池服務(wù)，將service層做的事情都提交到線程池中去處理；

springboot的線程池配置

創(chuàng)建一個(gè)配置類ExecutorConfig，用來(lái)定義如何創(chuàng)建一個(gè)ThreadPoolTaskExecutor，要使用@Configuration和@EnableAsync這兩個(gè)注解，表示這是個(gè)配置類，并且是線程池的配置類，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();
//配置核心線程數(shù)
executor.setCorePoolSize(5);
//配置最大線程數(shù)
executor.setMaxPoolSize(5);
//配置隊(duì)列大小
executor.setQueueCapacity(99999);
//配置線程池中的線程的名稱前綴
executor.setThreadNamePrefix("async-service-");
// rejection-policy：當(dāng)pool已經(jīng)達(dá)到max size的時(shí)候，如何處理新任務(wù)
// CALLER_RUNS：不在新線程中執(zhí)行任務(wù)，而是有調(diào)用者所在的線程來(lái)執(zhí)行
executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
//執(zhí)行初始化
executor.initialize();
return executor;
}
}

注意，上面的方法名稱為asyncServiceExecutor，稍后馬上用到；

將Service層的服務(wù)異步化

打開(kāi)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方法進(jìn)入的線程池是asyncServiceExecutor方法創(chuàng)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");
}

驗(yàn)證效果

將這個(gè)springboot運(yùn)行起來(lái)（pom.xml所在文件夾下執(zhí)行mvn spring-boot:run）；
在瀏覽器輸入：http://localhost:8080；
在瀏覽器用F5按鈕快速多刷新幾次；
在springboot的控制臺(tái)看見(jiàn)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，我們可以看到controller的執(zhí)行線程是"nio-8080-exec-8"，這是tomcat的執(zhí)行線程，而service層的日志顯示線程名為“async-service-1”，顯然已經(jīng)在我們配置的線程池中執(zhí)行了，并且每次請(qǐng)求中，controller的起始和結(jié)束日志都是連續(xù)打印的，表明每次請(qǐng)求都快速響應(yīng)了，而耗時(shí)的操作都留給線程池中的線程去異步執(zhí)行；

擴(kuò)展ThreadPoolTaskExecutor

雖然我們已經(jīng)用上了線程池，但是還不清楚線程池當(dāng)時(shí)的情況，有多少線程在執(zhí)行，多少在隊(duì)列中等待呢？這里我創(chuàng)建了一個(gè)ThreadPoolTaskExecutor的子類，在每次提交線程的時(shí)候都會(huì)將當(dāng)前線程池的運(yùn)行狀況打印出來(lái)，代碼如下：

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方法中將任務(wù)總數(shù)、已完成數(shù)、活躍線程數(shù)，隊(duì)列大小都打印出來(lái)了，然后Override了父類的execute、submit等方法，在里面調(diào)用showThreadPoolInfo方法，這樣每次有任務(wù)被提交到線程池的時(shí)候，都會(huì)將當(dāng)前線程池的基本情況打印到日志中；

修改ExecutorConfig.java的asyncServiceExecutor方法，將ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor()改為ThreadPoolTaskExecutor executor = new VisiableThreadPoolTaskExecutor()，如下所示：

@Bean
public Executor asyncServiceExecutor() {
logger.info("start asyncServiceExecutor");
//使用VisiableThreadPoolTaskExecutor
ThreadPoolTaskExecutor executor = new VisiableThreadPoolTaskExecutor();
//配置核心線程數(shù)
executor.setCorePoolSize(5);
//配置最大線程數(shù)
executor.setMaxPoolSize(5);
//配置隊(duì)列大小
executor.setQueueCapacity(99999);
//配置線程池中的線程的名稱前綴
executor.setThreadNamePrefix("async-service-");
// rejection-policy：當(dāng)pool已經(jīng)達(dá)到max size的時(shí)候，如何處理新任務(wù)
// CALLER_RUNS：不在新線程中執(zhí)行任務(wù)，而是有調(diào)用者所在的線程來(lái)執(zhí)行
executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
//執(zhí)行初始化
executor.initialize();
return executor;
}

再次啟動(dòng)該工程，再瀏覽器反復(fù)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

注意這一行日志：2. do submit,taskCount [101], completedTaskCount [87], activeCount [5], queueSize [9]

這說(shuō)明提交任務(wù)到線程池的時(shí)候，調(diào)用的是submit(Callable task)這個(gè)方法，當(dāng)前已經(jīng)提交了101個(gè)任務(wù)，完成了87個(gè)，當(dāng)前有5個(gè)線程在處理任務(wù)，還剩9個(gè)任務(wù)在隊(duì)列中等待，線程池的基本情況一路了然；

至此，springboot線程池服務(wù)的實(shí)戰(zhàn)就完成了，希望能幫您在工程中快速實(shí)現(xiàn)異步服務(wù)；

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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