Spring Batch -----Hello world!

Spring Batch 之 Sample（Hello World）

      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/con 11551
text/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.xsd http://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();
}
}
}

此处运行可能会报

		如下错误：（spring 3.0 + batch 2.1.8）Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jobRepository' defined in class path resource [applicationContext.xml]: Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: org/aopalliance/aop/Advice。。。at com.zhuhan.springbatch.JobLaunch.main(JobLaunch.java:16)

加入一个aopalliance.jar   jar包就可以了