1. 定时任务实现方式
定时任务实现方式：
定时任务执行方式：
2. 创建定时任务
package com.autonavi.task.test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import com.autonavi.task.ScheduledTasks;
@Component
public class ScheduledTest {
private static final Logger logger = LoggerFactory.getLogger(ScheduledTasks.class);
@Scheduled(cron="0 0/2 * * * ?")
public void executeFileDownLoadTask() {
// 间隔2分钟,执行任务
Thread current = Thread.currentThread();
System.out.println("定时任务1:"+current.getId());
logger.info("ScheduledTest.executeFileDownLoadTask 定时任务1:"+current.getId()+ ",name:"+current.getName());
}
}
@Scheduled 注解用于标注这个方法是一个定时任务的方法，有多种配置可选。cron支持cron表达式，指定任务在特定时间执行；fixedRate以特定频率执行任务；fixedRateString以string的形式配置执行频率。
3. 启动定时任务
@SpringBootApplication
@EnableScheduling
public class App {
private static final Logger logger = LoggerFactory.getLogger(App.class);
public static void main(String[] args) {
SpringApplication.run(App.class, args);
logger.info("start");
}
}
其中 @EnableScheduling 注解的作用是发现注解@Scheduled的任务并后台执行。
Springboot本身默认的执行方式是串行执行，也就是说无论有多少task，都是一个线程串行执行，并行需手动配置
4. 并行任务
继承SchedulingConfigurer类并重写其方法即可，如下：
@Configuration
@EnableScheduling
public class ScheduleConfig implements SchedulingConfigurer {
@Override
public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
taskRegistrar.setScheduler(taskExecutor());
}
@Bean(destroyMethod="shutdown")
public Executor taskExecutor() {
return Executors.newScheduledThreadPool(100);
}
}
再次执行之前的那个Demo，会欣然发现已经是并行执行了！
5. 异步并行任务
import org.springframework.scheduling.TaskScheduler;
import org.springframework.scheduling.annotation.AsyncConfigurer;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
@Configuration
@EnableScheduling
@EnableAsync(
mode = AdviceMode.PROXY, proxyTargetClass = false,
order = Ordered.HIGHEST_PRECEDENCE
)
@ComponentScan(
basePackages = "hello"
)
public class RootContextConfiguration implements
AsyncConfigurer, SchedulingConfigurer {
@Bean
public ThreadPoolTaskScheduler taskScheduler()
{
ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
scheduler.setPoolSize(20);
scheduler.setThreadNamePrefix("task-");
scheduler.setAwaitTerminationSeconds(60);
scheduler.setWaitForTasksToCompleteOnShutdown(true);
return scheduler;
}
@Override
public Executor getAsyncExecutor()
{
Executor executor = this.taskScheduler();
return executor;
}
@Override
public void configureTasks(ScheduledTaskRegistrar registrar)
{
TaskScheduler scheduler = this.taskScheduler();
registrar.setTaskScheduler(scheduler);
}
}
在启动的main方法加入额外配置：
@SpringBootApplication
public class Application {
public static void main(String[] args) throws Exception {
AnnotationConfigApplicationContext rootContext =
new AnnotationConfigApplicationContext();
rootContext.register(RootContextConfiguration.class);
rootContext.refresh();
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。
