spring cloud之spring cloud task

迷南。 2022-02-25 06:04 269阅读 0赞

## 1. 简介 ##

SpringCloud任务允许用户使用SpringCloud开发和运行短期的微服务，在本地 、云环境中、甚至在SpringCloud Data Flow上运行它们。仅添加注解@EnableTask便可将app作为spring boot app运行。  
spring cloud task让创建短期的微服务变得很容易。它提供的功能允许在生产环境中按需执行短期的JVM进程。

## 2. 环境要求 ##

Java8级更高版本  
spring cloud task使用RDB来存储任务运行的结果，当然开发的时候也可以不适用数据库，任务的状态作为taskrepository更新的一部分进行记录。目前支持的RDB有：

*  DB2
 *  H2
 *  HSQLDB
 *  MySql
 *  Oracle
 *  Postgres
 *  SqlServer

## 3. Spring Cloud Task之Hello World ##

*Hello World*  
引入依赖

<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-task</artifactId>
    		</dependency>

启动类

@SpringBootApplication(scanBasePackages = {"com.yuyan"})
    @ComponentScan({"com.yuyan"})
    @EnableTask
    public class StarterApplication {
    
    	private static final Logger log = LoggerFactory.getLogger(StarterApplication.class);
    
    	public static void main(String[] args) {
    		SpringApplication.run(StarterApplication.class, args);
    	}
    	
    	@Bean
    	public CommandLineRunner commandLineRunner() {
    		return new HelloWorldCommandLineRunner();
    	}
    
    	public static class HelloWorldCommandLineRunner implements CommandLineRunner {
    
    		@Override
    		public void run(String... strings) throws Exception {
    			log.info("running a task!!!!");
    		}
    	}
    }

application.properties

spring.application.name=task1
    
    logging.level.org.springframework.cloud.task=DEBUG

*CommandLineRunner*

*@EnableTask*  
这个类级注解用来开启Spring Cloud Task的功能。默认情况下，会引入一个附加的配置类SimpleTaskConfiguration，这个附加的配置会注册taskrepository和基础资源以供使用。  
TaskRepository使用内存的Map来保存Task执行的结果。这个Map在生产环境中并不是有效的解决方案，因为这个Map会随着任务的结束而销毁。  
*CommandLineRunner*  
![在这里插入图片描述][20190401014532362.png]  
*SimpleTaskRepository*  
默认任务仓库

## 4. 生命周期 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjE0MjA0Mg_size_16_color_FFFFFF_t_70]  
实现接口TaskExecutionListener监听任务的状态

@Component
    public class MyTaskListener implements TaskExecutionListener {
    
        private static final Logger log = LoggerFactory.getLogger(MyTaskListener.class);
    
    
        @Override
        public void onTaskStartup(TaskExecution taskExecution) {
            log.info("starting task:" + taskExecution.getTaskName());
        }
    
        @Override
        public void onTaskEnd(TaskExecution taskExecution) {
            log.info("ending task:" + taskExecution.getTaskName());
        }
    
        @Override
        public void onTaskFailed(TaskExecution taskExecution, Throwable throwable) {
            log.info("task failed:" + taskExecution.getTaskName());
            log.error("error msg:", throwable);
        }
    }

![在这里插入图片描述][20190401113313357.png]

## 5. 为任务配置数据源 ##

引入jpa的依赖

<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-data-jpa</artifactId>
    		</dependency>

修改application.properties

spring.datasource.driver-class-name=org.postgresql.Driver
    spring.datasource.url=jdbc:postgresql://127.0.0.1:5432/test?useUnicode=true&characterEncoding=UTF-8
    spring.datasource.username=postgres
    spring.datasource.password=root
    
    spring.jpa.show-sql=true
    spring.jpa.hibernate.ddl-auto=update
    spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.PostgreSQLDialect
    spring.jpa.properties.hibernate.temp.use_jdbc_metadata_defaults = false
    spring.jackson.serialization.indent-output=false

为TaskConfigurer配置数据源

@Autowired
        private DataSource dataSource;
    
        @Bean
        public DefaultTaskConfigurer getTaskConfigurer() {
            return new DefaultTaskConfigurer(dataSource);
        }

运行task之后数据库中增加如下四张表  
![在这里插入图片描述][20190404110444896.png]  
task\_execution记录了刚刚任务执行的起始时间、结果等数据  
![在这里插入图片描述][20190404110508145.png]

## 6. 集成Spring Batch ##

引入spring batch依赖

<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-batch</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-task-batch</artifactId>
    		</dependency>

application.properties中增加

spring.batch.initialize-schema=always

JobConfiguration

@Autowired
        public JobBuilderFactory jobBuilderFactory;
    
        @Autowired
        public StepBuilderFactory stepBuilderFactory;
        
        @Bean
        public Job job1() {
            return this.jobBuilderFactory.get("job1")
                    .start(this.stepBuilderFactory.get("job1step1")
                            .tasklet(new Tasklet() {
                                @Override
                                public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
                                    logger.info("Job1 was run");
                                    return RepeatStatus.FINISHED;
                                }
                            })
                            .build())
                    .build();
        }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjE0MjA0Mg_size_16_color_FFFFFF_t_70 1]  
Spring Batch的东西远不止这些。。。

## 7. 任务实例个数的限制 ##

引入依赖

<dependency>
    			<groupId>org.springframework.integration</groupId>
    			<artifactId>spring-integration-core</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.integration</groupId>
    			<artifactId>spring-integration-jdbc</artifactId>
    		</dependency>

spring.cloud.task.single-instance-enabled为true表示同一个时刻只能有一个叫这个名字的task执行，否则会抛出Task with name “application” is already running.

#限制同一个时刻只能有一个同名任务执行
    spring.cloud.task.single-instance-enabled=true

[20190401014532362.png]: /images/20220225/1d0b3a24f2b24a368c231e54bbf6f672.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjE0MjA0Mg_size_16_color_FFFFFF_t_70]: /images/20220225/6a7b613492c7489bbae316ed27e4efe6.png
[20190401113313357.png]: /images/20220225/60fa3acbf6224a72b8b10da23af935cb.png
[20190404110444896.png]: /images/20220225/4a2a6b23e8ba4e19b654a8779c779c7e.png
[20190404110508145.png]: /images/20220225/8c792d26764f4c51a554b4364e4a6e81.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zNjE0MjA0Mg_size_16_color_FFFFFF_t_70 1]: /images/20220225/ce5e066a7fcb4f54b8ebc5b4459f13f1.png