spring通過任務執行器(TaskExecutor)來實現多執行緒和併發程式設計。
ThreadPoolTaskExecutor可實現一個基於執行緒池的TaskExecutor。
實際開發中任務一般是非阻礙的,即非同步的，通過@EnableAsync開啟對非同步任務的支援，
並通過實際執行的Bean的方法中使用@Async註解來宣告其是一個非同步任務。

[email protected] //1標識是是非同步方法

package com.zh.ch3.taskexecutor;

import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
@Service
public class AsyncTaskService {
	
	@Async //1標識是是非同步方法
    public void executeAsyncTask(Integer i){
        System.out.println("執行非同步任務: "+i);
    }

    @Async
    public void executeAsyncTaskPlus(Integer i){
        System.out.println("執行非同步任務:+1: "+(i+1));
    }

}
 

package com.zh.ch3.taskexecutor;

import java.util.concurrent.Executor;

import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.AsyncConfigurer;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

@Configuration
@ComponentScan("com.zh.ch3.taskexecutor")
@EnableAsync // 1開啟非同步任務支援
public class TaskExecutorConfig implements AsyncConfigurer {// 2配置AsyncConfigurer並重寫getAsyncExecutor

	@Override
	public Executor getAsyncExecutor() {// 2
		ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
		taskExecutor.setCorePoolSize(5);
		taskExecutor.setMaxPoolSize(10);
		taskExecutor.setQueueCapacity(25);
		taskExecutor.initialize();
		return taskExecutor;
	}

	@Override
	public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
		return null;
	}

}
 

package com.zh.ch3.taskexecutor;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Main {

	public static void main(String[] args) {
		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(TaskExecutorConfig.class);

		AsyncTaskService asyncTaskService = context.getBean(AsyncTaskService.class);

		for (int i = 0; i < 10; i++) {
			asyncTaskService.executeAsyncTask(i);
			asyncTaskService.executeAsyncTaskPlus(i);
		}
		context.close();
	}
}
 

執行非同步任務: 3
執行非同步任務: 1
執行非同步任務: 4
執行非同步任務:+1: 1
執行非同步任務: 5
執行非同步任務:+1: 6
執行非同步任務: 6
執行非同步任務:+1: 7
執行非同步任務: 7
執行非同步任務:+1: 8
=======================================================================

@EnableScheduling開啟計劃任務

1.

[email protected]:宣告該方法是一個計劃任務，fixedRate屬性設定每隔固定時間執行

2cron屬性：按照指定時間執行(11時28)cron事unix和類unix(linux)系統下的定時時間

package com.zh.ch3.taskscheduler;

import java.text.SimpleDateFormat;
import java.util.Date;

import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;

@Service
public class ScheduledTaskService {

	private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");

	@Scheduled(fixedRate = 5000) // [email protected]:宣告該方法是一個計劃任務，fixedRate屬性設定每隔固定時間執行
	public void reportCurrentTime() {
		System.out.println("每隔5秒執行一次： " + dateFormat.format(new Date()));
	}

	@Scheduled(cron = "0 28 11 ? * *") // 2cron屬性：按照指定時間執行(11時28)cron事unix和類unix(linux)系統下的定時時間
	public void fixTimeExecution() {
		System.out.println("在指定時間內執行一次： " + dateFormat.format(new Date()) + "執行");
	}

}

package com.zh.ch3.taskscheduler;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableScheduling;

@Configuration
@ComponentScan("com.zh.ch3.taskscheduler")
@EnableScheduling //[email protected]：開啟計劃任務的支援
public class TaskSchedulerConfig {

}

package com.zh.ch3.taskscheduler;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Main {
	public static void main(String[] args) {
		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(TaskSchedulerConfig.class);

	}

}