通过前面两篇关于Spring Batch文章的介绍,大家应该已经对Spring Batch有个初步的概念了。这篇文章,将通过一个”Hello World!”实例,和大家一起探讨关于Spring Batch的一些基本配置和实现。使大家从开发的角度对Spring Batch有一个真切的体会。
说明:1,本实例使用的是spring-batch 2.1.8
2,本实例没有像前面讲的那样配置ItemReader、ItemProcessor和ItemWriter,而是之间在Step中调用Tasklet,由Tasklet完成”Hello World!”的输出。
工程结构如下图:
JobLaunch.java类用来启动Bath,writeTasklet.java用来完成输出工作。application.xml用来配置一些Spring信息,batch.xml配置Job信息。
application.xml文件配置如下:
<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd" default-autowire="byName"> <bean id="jobLauncher"class="org.springframework.batch.core.launch.support.SimpleJobLauncher"> <property name="jobRepository" ref="jobRepository"/> </bean> <bean id="jobRepository"class="org.springframework.batch.core.repository.support.MapJobRepositoryFactoryBean"> </bean> <bean id="transactionManager" class="org.springframework.batch.support.transaction.ResourcelessTransactionManager"/></beans>
jobLauncher负责batch的启动工作,jobRepository负责job的整个运行过程中的CRUD操作,transactionManager负责事务的管理操作。
batch.xml文件配置如下:
<?xml version="1.0" encoding="UTF-8"?><bean:beans xmlns="http://www.springframework.org/schema/batch" xmlns:bean="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsdhttp://www.springframework.org/schema/batch http://www.springframework.org/schema/batch/spring-batch-2.1.xsd"> <bean:import resource="applicationContext.xml"/> <job id="helloWorldJob"> <step id="step_hello" next="step_world"> <tasklet ref="hello" transaction-manager="transactionManager"></tasklet> </step> <step id="step_world"> <tasklet ref="world" transaction-manager="transactionManager"></tasklet> </step> </job> <bean:bean id="hello" class="com.wanggc.springbatch.sample.helloworld.writeTasklet"> <bean:property name="message" value="Hello "></bean:property> </bean:bean> <bean:bean id="world" class="com.wanggc.springbatch.sample.helloworld.writeTasklet"> <bean:property name="message" value=" World!"></bean:property> </bean:bean></bean:beans>
配置了一个ID为helloWorldJob的job,此job有两个Step : step_hello和step_world,前者负责输出“Hello ”,后者负责输出“World!”,当第一个Step完成以后,执行第二个Step。
writeTasklet类的代码如下:
public class writeTasklet implements Tasklet { /** Message */ private String message; /** * @param message * the message to set */ public void setMessage(String message) { this.message = message; } @Override public RepeatStatus execute(StepContribution arg0, ChunkContext arg1) throws Exception { System.out.println(message); return RepeatStatus.FINISHED; } }
此类中定义了一个message属性,通过batch.xml的“hello”和“world” Bean为其注入值。 execute方法,是由Tasklet接口继承而来的,是Tasklet实现业务逻辑的地方。此实例中只是简单的输出Message信息后,直接返回。
启动类JobLaunch类的代码如下:
public class JobLaunch { /** * @param args */ public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext( "batch.xml"); JobLauncher launcher = (JobLauncher) context.getBean("jobLauncher"); Job job = (Job) context.getBean("helloWorldJob"); try { /* 运行Job */ JobExecution result = launcher.run(job, new JobParameters()); /* 处理结束,控制台打印处理结果 */ System.out.println(result.toString()); } catch (Exception e) { e.printStackTrace(); } }}