Spring Batch_实现Tasklet

Spring Batch_实现Tasklet

    Chunk-oriented processing is not the only way to process in a Step. What if a Step must consist as a simple stored procedure call? You could implement the call as an ItemReader and return null after the procedure finishes, but it is a bit unnatural since there would need to be a no-op ItemWriter. Spring Batch provides the TaskletStep for this scenario.

    The Tasklet is a simple interface that has one method, execute, which will be a called repeatedly by the TaskletStep until it either returns RepeatStatus.FINISHED or throws an exception to signal a failure. Each call to the Tasklet is wrapped in a transaction. Tasklet implementors might call a stored procedure, a script, or a simple SQL update statement. To create a TaskletStep, the 'ref' attribute of the <tasklet/> element should reference a bean defining a Tasklet object; no <chunk/> element should be used within the <tasklet/>:

http://docs.spring.io/spring-batch/trunk/reference/html/configureStep.html#exampleTaskletImplementation

如下的配置：

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:batch="http://www.springframework.org/schema/batch"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
		http://www.springframework.org/schema/batch http://www.springframework.org/schema/batch/spring-batch.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

	<!--执行文件删除的任务 -->
	<batch:job id="taskletJob">
		<batch:step id="deleteFilesInDir">
			<batch:tasklet ref="fileDeletingTasklet" />
		</batch:step>
	</batch:job>

	<bean id="fileDeletingTasklet" class="com.lyx.batch.FileDeletingTasklet">
		<property name="directoryResource" ref="directoryResource" />
	</bean>
	<bean id="directoryResource" class="org.springframework.core.io.FileSystemResource">
		<constructor-arg value="E:\workspace2\SpringBatch2\target" />
	</bean>

	<!--tomcat jdbc pool数据源配置 -->
	<bean id="dataSource" class="org.apache.tomcat.jdbc.pool.DataSource"
		destroy-method="close">
		<property name="poolProperties">
			<bean class="org.apache.tomcat.jdbc.pool.PoolProperties">
				<property name="driverClassName" value="com.mysql.jdbc.Driver" />
				<property name="url" value="jdbc:mysql://localhost:3306/test" />
				<property name="username" value="root" />
				<property name="password" value="034039" />
			</bean>
		</property>
	</bean>

	<!-- spring batch 配置jobRepository -->
	<batch:job-repository id="jobRepository"
		data-source="dataSource" transaction-manager="transactionManager"
		isolation-level-for-create="REPEATABLE_READ" table-prefix="BATCH_"
		max-varchar-length="1000" />
	<!-- spring的事务管理器 -->
	<bean id="transactionManager"
		class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
		<property name="dataSource" ref="dataSource" />
	</bean>

	<!-- batch luncher -->
	<bean id="jobLauncher"
		class="org.springframework.batch.core.launch.support.SimpleJobLauncher">
		<property name="jobRepository" ref="jobRepository" />
	</bean>
</beans>

类实现：

package com.lyx.batch;

import java.io.File;

import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.UnexpectedJobExecutionException;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;

public class FileDeletingTasklet implements Tasklet, InitializingBean {

	private Resource directory;

	/**
	 * 实现execute方法
	 */
	public RepeatStatus execute(StepContribution contribution,
			ChunkContext chunkContext) throws Exception {
		File dir = this.directory.getFile();
		Assert.state(dir.isDirectory());

		File[] files = dir.listFiles();
		for (int i = 0; i < files.length; i++) {
			boolean deleted = files[i].delete();
			if (!deleted) {
				throw new UnexpectedJobExecutionException(
						"Could not delete file " + files[i].getPath());
			}
		}
		return RepeatStatus.FINISHED;
	}

	public void setDirectoryResource(Resource directory) {
		this.directory = directory;
	}

	public void afterPropertiesSet() throws Exception {
		Assert.notNull(this.directory, "directory must be set");
	}
}

运行：

package com.lyx.batch;

import org.springframework.batch.core.ExitStatus;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.JobParametersBuilder;
import org.springframework.batch.core.JobParametersInvalidException;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.batch.core.repository.JobExecutionAlreadyRunningException;
import org.springframework.batch.core.repository.JobInstanceAlreadyCompleteException;
import org.springframework.batch.core.repository.JobRestartException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class AppMain15 {
	public static void main(String[] args)
			throws JobExecutionAlreadyRunningException, JobRestartException,
			JobInstanceAlreadyCompleteException, JobParametersInvalidException {

		long startTime = System.currentTimeMillis(); // 获取开始时间

		@SuppressWarnings("resource")
		ApplicationContext context = new ClassPathXmlApplicationContext(
				new String[] { "classpath:spring-batch-sample-tasklet.xml" });
		JobParametersBuilder jobParametersBuilder = new JobParametersBuilder();
		Job job = (Job) context.getBean("taskletJob");
		JobLauncher launcher = (JobLauncher) context.getBean("jobLauncher");
		JobExecution result = launcher.run(job,
				jobParametersBuilder.toJobParameters());
		ExitStatus es = result.getExitStatus();
		if (es.getExitCode().equals(ExitStatus.COMPLETED.getExitCode())) {
			System.out.println("任务正常完成");
		} else {
			System.out.println("任务失败，exitCode=" + es.getExitCode());
		}

		long endTime = System.currentTimeMillis(); // 获取结束时间
		System.out.println("程序运行时间： " + (endTime - startTime) + "ms");
	}
}

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