專案結果：

1、     專案所需的jar包，因為是SpringBoot的demo,所以這裡只需要引入spring-boot-starter-parent和spring-boot-starter-web即可。

pom.xml:

<?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.springboot</groupId>
    <artifactId>scheduled-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>scheduled-demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.6.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>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>
 

1、啟動類：加上@EnableScheduling，這樣才會去掃描@Scheduled的方法，去掉之後@Scheduled的方法將不會被執行。

package com.springboot.scheduleddemo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;

@SpringBootApplication
@EnableScheduling
public class ScheduledDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(ScheduledDemoApplication.class, args);
    }
}
 

2、寫定時任務：

參考：線上Cron表示式

@Scheduled() 註解中寫入Cron表示式。

此處將類加上@Component註解或者@Service均可。

"0/1 * * * * ? "表示每秒執行一次

package com.springboot.scheduleddemo.service;

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

import java.util.Date;

/**
 * @author: Lucifer
 * @create: 2018-10-29 22:39
 * @description:
 **/
@Component
public class ScheduledService {

    @Scheduled(cron = "0/1 * * * * ? ")
    public void sayHello(){
        System.out.println("定時任務1："+new Date());
    }

}
 

控制檯：

3、加入SayNo方法

@Scheduled(cron = "0/1 * * * * ? ")
    public void sayNo(){
        System.out.println("定時任務2"+new Date()+".......No");
    }

此時啟動，會看到控制檯如下圖：此時是同步的，序列，先執行sayHello，再執行SayNo.

4、加上@Async

@SpringBootApplication
@EnableScheduling
@Async
public class ScheduledDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(ScheduledDemoApplication.class, args);
    }
}

再次檢視控制檯：如圖

此時不再是按順序去執行了，而是非同步。在啟動類加上@Async，表示執行的是非同步的