Part1前言

前兩天做項目的時候，想提高一下插入表的性能優(yōu)化，因為是兩張表，先插舊的表，緊接著插新的表，一萬多條數(shù)據(jù)就有點慢了

后面就想到了線程池ThreadPoolExecutor，而用的是Spring Boot項目，可以用Spring提供的對ThreadPoolExecutor封裝的線程池ThreadPoolTaskExecutor，直接使用注解啟用

Part2使用步驟

先創(chuàng)建一個線程池的配置，讓Spring Boot加載，用來定義如何創(chuàng)建一個ThreadPoolTaskExecutor，要使用@Configuration和@EnableAsync這兩個注解，表示這是個配置類，并且是線程池的配置類

@Configuration
@EnableAsync
public?class?ExecutorConfig?{

????private?static?final?Logger?logger?=?LoggerFactory.getLogger(ExecutorConfig.class);

????@Value("${async.executor.thread.core_pool_size}")
????private?int?corePoolSize;
????@Value("${async.executor.thread.max_pool_size}")
????private?int?maxPoolSize;
????@Value("${async.executor.thread.queue_capacity}")
????private?int?queueCapacity;
????@Value("${async.executor.thread.name.prefix}")
????private?String?namePrefix;

????@Bean(name?=?"asyncServiceExecutor")
????public?Executor?asyncServiceExecutor()?{
????????logger.info("start?asyncServiceExecutor");
????????ThreadPoolTaskExecutor?executor?=?new?ThreadPoolTaskExecutor();
????????//配置核心線程數(shù)
????????executor.setCorePoolSize(corePoolSize);
????????//配置最大線程數(shù)
????????executor.setMaxPoolSize(maxPoolSize);
????????//配置隊列大小
????????executor.setQueueCapacity(queueCapacity);
????????//配置線程池中的線程的名稱前綴
????????executor.setThreadNamePrefix(namePrefix);

????????// rejection-policy：當pool已經(jīng)達到max size的時候，如何處理新任務
????????// CALLER_RUNS：不在新線程中執(zhí)行任務，而是有調用者所在的線程來執(zhí)行
????????executor.setRejectedExecutionHandler(new?ThreadPoolExecutor.CallerRunsPolicy());
????????//執(zhí)行初始化
????????executor.initialize();
????????return?executor;
????}
}

@Value是我配置在application.properties，可以參考配置，自由定義

#?異步線程配置
#?配置核心線程數(shù)
async.executor.thread.core_pool_size?=?5
#?配置最大線程數(shù)
async.executor.thread.max_pool_size?=?5
#?配置隊列大小
async.executor.thread.queue_capacity?=?99999
#?配置線程池中的線程的名稱前綴
async.executor.thread.name.prefix?=?async-service-

創(chuàng)建一個Service接口，是異步線程的接口

public?interface?AsyncService?{
????/**
?????*?執(zhí)行異步任務
?????*?可以根據(jù)需求，自己加參數(shù)擬定，我這里就做個測試演示
?????*/
????void?executeAsync();
}

實現(xiàn)類

@Service
public?class?AsyncServiceImpl?implements?AsyncService?{
????private?static?final?Logger?logger?=?LoggerFactory.getLogger(AsyncServiceImpl.class);

????@Override
????@Async("asyncServiceExecutor")
????public?void?executeAsync()?{
????????logger.info("start?executeAsync");

????????System.out.println("異步線程要做的事情");
????????System.out.println("可以在這里執(zhí)行批量插入等耗時的事情");

????????logger.info("end?executeAsync");
????}
}

將Service層的服務異步化，在executeAsync()方法上增加注解@Async("asyncServiceExecutor")，asyncServiceExecutor方法是前面ExecutorConfig.java中的方法名，表明executeAsync方法進入的線程池是asyncServiceExecutor方法創(chuàng)建的

接下來就是在Controller里或者是哪里通過注解@Autowired注入這個Service

@Autowired
private?AsyncService?asyncService;

@GetMapping("/async")
public?void?async(){
????asyncService.executeAsync();
}

用postmain或者其他工具來多次測試請求一下

2018-07-16?22:15:47.655??INFO?10516?---?[async-service-5]?c.u.d.e.executor.impl.AsyncServiceImpl???:?start?executeAsync
異步線程要做的事情
可以在這里執(zhí)行批量插入等耗時的事情
2018-07-16?22:15:47.655??INFO?10516?---?[async-service-5]?c.u.d.e.executor.impl.AsyncServiceImpl???:?end?executeAsync
2018-07-16?22:15:47.770??INFO?10516?---?[async-service-1]?c.u.d.e.executor.impl.AsyncServiceImpl???:?start?executeAsync
異步線程要做的事情
可以在這里執(zhí)行批量插入等耗時的事情
2018-07-16?22:15:47.770??INFO?10516?---?[async-service-1]?c.u.d.e.executor.impl.AsyncServiceImpl???:?end?executeAsync
2018-07-16?22:15:47.816??INFO?10516?---?[async-service-2]?c.u.d.e.executor.impl.AsyncServiceImpl???:?start?executeAsync
異步線程要做的事情
可以在這里執(zhí)行批量插入等耗時的事情
2018-07-16?22:15:47.816??INFO?10516?---?[async-service-2]?c.u.d.e.executor.impl.AsyncServiceImpl???:?end?executeAsync
2018-07-16?22:15:48.833??INFO?10516?---?[async-service-3]?c.u.d.e.executor.impl.AsyncServiceImpl???:?start?executeAsync
異步線程要做的事情
可以在這里執(zhí)行批量插入等耗時的事情
2018-07-16?22:15:48.834??INFO?10516?---?[async-service-3]?c.u.d.e.executor.impl.AsyncServiceImpl???:?end?executeAsync
2018-07-16?22:15:48.986??INFO?10516?---?[async-service-4]?c.u.d.e.executor.impl.AsyncServiceImpl???:?start?executeAsync
異步線程要做的事情
可以在這里執(zhí)行批量插入等耗時的事情
2018-07-16?22:15:48.987??INFO?10516?---?[async-service-4]?c.u.d.e.executor.impl.AsyncServiceImpl???:?end?executeAsync

通過以上日志可以發(fā)現(xiàn)，[async-service-]是有多個線程的，顯然已經(jīng)在我們配置的線程池中執(zhí)行了，并且每次請求中，controller的起始和結束日志都是連續(xù)打印的，表明每次請求都快速響應了，而耗時的操作都留給線程池中的線程去異步執(zhí)行；

雖然我們已經(jīng)用上了線程池，但是還不清楚線程池當時的情況，有多少線程在執(zhí)行，多少在隊列中等待呢？這里我創(chuàng)建了一個ThreadPoolTaskExecutor的子類，在每次提交線程的時候都會將當前線程池的運行狀況打印出來

import?org.slf4j.Logger;
import?org.slf4j.LoggerFactory;
import?org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import?org.springframework.util.concurrent.ListenableFuture;

import?java.util.concurrent.Callable;
import?java.util.concurrent.Future;
import?java.util.concurrent.ThreadPoolExecutor;

/**
?*?@Author:?ChenBin
?*?@Date:?2018/7/16/0016?22:19
?*/
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??Future?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方法中將任務總數(shù)、已完成數(shù)、活躍線程數(shù)，隊列大小都打印出來了，然后Override了父類的execute、submit等方法，在里面調用showThreadPoolInfo方法，這樣每次有任務被提交到線程池的時候，都會將當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()

@Bean(name?=?"asyncServiceExecutor")
public?Executor?asyncServiceExecutor()?{
????logger.info("start?asyncServiceExecutor");
????//在這里修改
????ThreadPoolTaskExecutor?executor?=?new?VisiableThreadPoolTaskExecutor();
????//配置核心線程數(shù)
????executor.setCorePoolSize(corePoolSize);
????//配置最大線程數(shù)
????executor.setMaxPoolSize(maxPoolSize);
????//配置隊列大小
????executor.setQueueCapacity(queueCapacity);
????//配置線程池中的線程的名稱前綴
????executor.setThreadNamePrefix(namePrefix);

????// rejection-policy：當pool已經(jīng)達到max size的時候，如何處理新任務
????// CALLER_RUNS：不在新線程中執(zhí)行任務，而是有調用者所在的線程來執(zhí)行
????executor.setRejectedExecutionHandler(new?ThreadPoolExecutor.CallerRunsPolicy());
????//執(zhí)行初始化
????executor.initialize();
????return?executor;
}

再次啟動該工程測試

2018-07-16?22:23:30.951??INFO?14088?---?[nio-8087-exec-2]?u.d.e.e.i.VisiableThreadPoolTaskExecutor?:?async-service-,?2.?do?submit,taskCount?[0],?completedTaskCount?[0],?activeCount?[0],?queueSize?[0]
2018-07-16?22:23:30.952??INFO?14088?---?[async-service-1]?c.u.d.e.executor.impl.AsyncServiceImpl???:?start?executeAsync
異步線程要做的事情
可以在這里執(zhí)行批量插入等耗時的事情
2018-07-16?22:23:30.953??INFO?14088?---?[async-service-1]?c.u.d.e.executor.impl.AsyncServiceImpl???:?end?executeAsync
2018-07-16?22:23:31.351??INFO?14088?---?[nio-8087-exec-3]?u.d.e.e.i.VisiableThreadPoolTaskExecutor?:?async-service-,?2.?do?submit,taskCount?[1],?completedTaskCount?[1],?activeCount?[0],?queueSize?[0]
2018-07-16?22:23:31.353??INFO?14088?---?[async-service-2]?c.u.d.e.executor.impl.AsyncServiceImpl???:?start?executeAsync
異步線程要做的事情
可以在這里執(zhí)行批量插入等耗時的事情
2018-07-16?22:23:31.353??INFO?14088?---?[async-service-2]?c.u.d.e.executor.impl.AsyncServiceImpl???:?end?executeAsync
2018-07-16?22:23:31.927??INFO?14088?---?[nio-8087-exec-5]?u.d.e.e.i.VisiableThreadPoolTaskExecutor?:?async-service-,?2.?do?submit,taskCount?[2],?completedTaskCount?[2],?activeCount?[0],?queueSize?[0]
2018-07-16?22:23:31.929??INFO?14088?---?[async-service-3]?c.u.d.e.executor.impl.AsyncServiceImpl???:?start?executeAsync
異步線程要做的事情
可以在這里執(zhí)行批量插入等耗時的事情
2018-07-16?22:23:31.930??INFO?14088?---?[async-service-3]?c.u.d.e.executor.impl.AsyncServiceImpl???:?end?executeAsync
2018-07-16?22:23:32.496??INFO?14088?---?[nio-8087-exec-7]?u.d.e.e.i.VisiableThreadPoolTaskExecutor?:?async-service-,?2.?do?submit,taskCount?[3],?completedTaskCount?[3],?activeCount?[0],?queueSize?[0]
2018-07-16?22:23:32.498??INFO?14088?---?[async-service-4]?c.u.d.e.executor.impl.AsyncServiceImpl???:?start?executeAsync
異步線程要做的事情
可以在這里執(zhí)行批量插入等耗時的事情
2018-07-16?22:23:32.499??INFO?14088?---?[async-service-4]?c.u.d.e.executor.impl.AsyncServiceImpl???:?end?executeAsync

注意這一行日志：

2018-07-16 22:23:32.496 INFO 14088 --- [nio-8087-exec-7] u.d.e.e.i.VisiableThreadPoolTaskExecutor : async-service-, 2. do submit,taskCount [3], completedTaskCount [3], activeCount [0], queueSize [0]

這說明提交任務到線程池的時候，調用的是submit(Callable task)這個方法，當前已經(jīng)提交了3個任務，完成了3個，當前有0個線程在處理任務，還剩0個任務在隊列中等待，線程池的基本情況一路了然；