在Java应用中,绝大多数情况下都是通过同步的方式来实现交互处理的;但是在处理与第三方系统交互的时候,容易造成响应迟缓的情况,之前大部分都是使用多线程来完成此类任务,其实,在Spring 3.x之后,就已经内置了@Async来完美解决这个问题。
主要使用两个注解完成,@EnableAysnc、@Aysnc
| @EnableAsync //开启异步注解功能 @SpringBootApplication public class Springboot04TaskApplication { 
 public static void main(String[] args) { SpringApplication.run(Springboot04TaskApplication.class, args); } 
 } | 
| package com.hosystem.task.controller; 
 import com.hosystem.task.service.AsyncService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RestController; 
 @RestController public class AsyncController { 
 @Autowired AsyncService asyncService; 
 @GetMapping("/hello") public String hello(){ asyncService.hello(); return "success"; } } | 
| package com.hosystem.task.service; 
 import org.springframework.scheduling.annotation.Async; import org.springframework.stereotype.Service; 
 @Service public class AsyncService { 
 //通知spring这是一个异步方法 @Async public void hello(){ try { Thread.sleep(3000); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("处理数据...."); } } | 
 
开发中经常需要执行一些定时任务,比如需要在每天凌晨时候,分析一次前一天的日志信息。Spring为我们提供了异步执行任务调度的方式,提供TaskExecutor 、TaskScheduler 接口。
使用到的注解有两个,@EnableScheduling、@Scheduled
Cron表达式:
 
| package com.hosystem.task.service; 
 import org.springframework.scheduling.annotation.Scheduled; import org.springframework.stereotype.Service; 
 @Service public class ScheduledService { 
 /** * second(秒), minute(分), hour(时), day of month(日), month(月), day of week(周几). * 0 * * * * MON-FRI * [0 0/5 14,18 * * ?]:每天14点整,和18点整,每隔5分钟执行一次 * [0 15 10 ? * 1-6]:每个月的周一至周六10:15分执行一次 * [0 0 2 ? * 6L]:每个月的最后一个周六凌晨2点执行一次 * [0 0 2 LW * ?]:每个月的最后一个工作日凌晨2点执行一次 * [0 0 2-4 ? * 1#1]:每个月的第一个周一凌晨2点到4点期间,每个整点都执行一次; */ // @Scheduled(cron = "0 * * * * MON-SAT") //@Scheduled(cron = "0,1,2,3,4 * * * * MON-SAT") // @Scheduled(cron = "0-4 * * * * MON-SAT") @Scheduled(cron = "0/4 * * * * 0-7") //每4秒执行一次 public void hello() { System.out.println("hello ..."); } } | 
| package com.hosystem.task; 
 import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.scheduling.annotation.EnableAsync; import org.springframework.scheduling.annotation.EnableScheduling; import org.springframework.scheduling.annotation.Scheduled; 
 @EnableScheduling //开启基于注解定时任务 @SpringBootApplication public class Springboot04TaskApplication { 
 public static void main(String[] args) { SpringApplication.run(Springboot04TaskApplication.class, args); } 
 } | 

 
| <!--mail--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-mail</artifactId> </dependency> | 



| server.port=80 
 #配置邮箱信息 spring.mail.username=username@qq.com #授权码 spring.mail.password=password #smtp地址 spring.mail.host=smtp.qq.com spring.mail.protocol=smtp spring.mail.properties.mail.smtp.ssl.enable=true | 
SendMailTest测试邮箱发送,一定要在mail中开启SMTP
| package com.hosystem.task; 
 import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.mail.SimpleMailMessage; import org.springframework.mail.javamail.JavaMailSenderImpl; import org.springframework.mail.javamail.MimeMessageHelper; 
 import javax.mail.internet.MimeMessage; import java.io.File; 
 @SpringBootTest class Springboot04TaskApplicationTests { 
 @Autowired JavaMailSenderImpl mailSender; 
 @Test public void contextLoads() { SimpleMailMessage simpleMailMessage = new SimpleMailMessage(); //邮件设置 simpleMailMessage.setSubject("通知-----"); simpleMailMessage.setText("学习java"); //setTo:目的邮件地址 setFrom:发送邮件地址 simpleMailMessage.setTo("username@163.com"); simpleMailMessage.setFrom("username@qq.com"); mailSender.send(simpleMailMessage); } 
 @Test public void test01() throws Exception{ //1.创建一个复杂的消息邮件 MimeMessage mimeMessage = mailSender.createMimeMessage(); MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, true); 
 //邮件设置 helper.setSubject("通知-----"); 
 /** * public void setText(String text) throws MessagingException {this.setText(text, false); } */ helper.setText("<b style=‘color:red‘>学习java</b>",true); //setTo:目的邮件地址 setFrom:发送邮件地址 helper.setTo("username@163.com"); helper.setFrom("username@qq.com"); 
 //上传文件 helper.addAttachment("8a92681cb892bf78ec83af62f2b6a82.jpg",new File("E:\\Users\\Asuna\\Desktop\\html\\8a92681cb892bf78ec83af62f2b6a82.jpg")); helper.addAttachment("8f82df421233241732db6ec6baed07e.jpg",new File("E:\\Users\\Asuna\\Desktop\\html\\8f82df421233241732db6ec6baed07e.jpg")); 
 
 mailSender.send(mimeMessage); } 
 } | 
  

原文:https://www.cnblogs.com/HOsystem/p/14028155.html