Spring Boot 面试热点

在Spring Boot中，有多种方式可以实现定时任务，以下是其中的几种方式：

1. 使用@Scheduled注解：

import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
 
@Component
public class ScheduledTask {
 
    @Scheduled(fixedRate = 5000)
    public void performTask() {
        System.out.println("Fixed rate task is executed");
    }
}

2. 使用ScheduledAnnotationBeanPostProcessor：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
import org.springframework.scheduling.support.CronSequenceGenerator;
 
@Configuration
@EnableScheduling
public class SchedulerConfig implements SchedulingConfigurer {
 
    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        taskRegistrar.addTriggerTask(
            // 定义执行任务内容
            () -> System.out.println("Cron task is executed"),
            // 设定cron时间触发规则
            triggerContext -> new CronSequenceGenerator("*/5 * * * * ?").next(triggerContext.lastCompletionTime()).getTime()
        );
    }
}

3. 使用TaskScheduler和TaskExecutor：

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.TaskScheduler;
import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
 
@Configuration
public class SchedulerConfig {
 
    @Bean
    public TaskScheduler taskScheduler() {
        ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
        scheduler.setPoolSize(5);
        scheduler.setThreadNamePrefix("my-scheduler-");
        scheduler.initialize();
        return scheduler;
    }
}

这些方法可以用来在Spring Boot应用中实现定时任务的需求。