Spring Batch_Configuring a Step for Restart

spring官方文档：http://docs.spring.io/spring-batch/trunk/reference/html/configureStep.html#stepRestart

当一个普通的 job 处于complete 的状态的时候，是不能被restart的。下面看如何使一个job 能够被 restart 。

restartable="true"

<job id="footballJob" restartable="false">
    ...
</job>

首先job应该要配置成 restartable="true"。

然后看step如何配置：

allow-start-if-complete="true"

这是设置当该step完成时，也可以重启。这个默认值是false。

start-limit="3"

这是设置可以重启的次数，默认值是Integer.MAX_VALUE.

这是spring 官方文档给的demo：

<job id="footballJob" restartable="true">
	<step id="playerload" next="gameLoad">
		<tasklet>
			<chunk reader="playerFileItemReader" writer="playerWriter"
				commit-interval="10" />
		</tasklet>
	</step>
	<step id="gameLoad" next="playerSummarization">
		<tasklet allow-start-if-complete="true">
			<chunk reader="gameFileItemReader" writer="gameWriter"
				commit-interval="10" />
		</tasklet>
	</step>
	<step id="playerSummarization">
		<tasklet start-limit="3">
			<chunk reader="playerSummarizationSource" writer="summaryWriter"
				commit-interval="10" />
		</tasklet>
	</step>
</job>

下面是我的关于restart的配置：

spring-batch-restart.xml

<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">
	<!-- 包的扫描 -->
	<context:component-scan base-package="com.lyx.batch" />

	<bean id="exceptionHandler" class="com.lyx.batch.ExceptionListener" />

	<batch:step id="abstractStep" abstract="true">
		<batch:listeners>
			<batch:listener ref="exceptionHandler" />
		</batch:listeners>
	</batch:step>
	<bean id="abstractCursorReader" abstract="true"
		class="org.springframework.batch.item.database.JdbcCursorItemReader">
		<property name="dataSource" ref="dataSource" />
	</bean>

	<!-- add people desc job begin  -->
	<batch:job id="addPeopleDescJob" restartable="true">
		<batch:step id="addDescStep" parent="abstractStep">
			<batch:tasklet allow-start-if-complete="true"
				start-limit="2">
				<batch:chunk reader="peopleAddDescReader" processor="addDescProcessor"
					writer="addDescPeopleWriter" commit-interval="2" />
			</batch:tasklet>
		</batch:step>
	</batch:job>
	<!-- add people desc job end  -->

	<bean id="peopleAddDescReader" parent="abstractCursorReader"
		scope="step">
		<property name="sql">
			<value><![CDATA[select first_name ,last_name from people where 
			first_name like ? or last_name like ?]]></value>
		</property>
		<property name="rowMapper" ref="peopleRowMapper" />
		<property name="preparedStatementSetter" ref="preparedStatementSetter" />
		<property name="fetchSize" value="20" />
	</bean>
	<bean id="peopleRowMapper" class="com.lyx.batch.PeopleRowMapper" />
	<bean id="preparedStatementSetter" class="com.lyx.batch.PeoplePreparedStatementSetter" />
	<bean id="addDescProcessor" class="com.lyx.batch.AddPeopleDescProcessor" />
	<bean id="addDescPeopleWriter" class="com.lyx.batch.AddDescPeopleWriter" />

	<!--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>

AppMain8.java

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;

/**
 * 测试restart
 * 
 * @author Lenovo
 *
 */
public class AppMain8 {
	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-restart.xml" });
		JobParametersBuilder jobParametersBuilder = new JobParametersBuilder();
		Job job = (Job) context.getBean("addPeopleDescJob");
		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");
	}

}

当我第一运行成功时：

select * from batch_job_instance;

JOB_INSTANCE_ID  VERSION  JOB_NAME          JOB_KEY                           
---------------  -------  ----------------  --------------------------------  
1                0        addPeopleDescJob  d41d8cd98f00b204e9800998ecf8427e

当我第二次运行成功时，查询一下相关的表：

select * from batch_job_execution;会发现有两个job_execution，都是属于一个job instance。

JOB_INSTANCE_ID  VERSION  JOB_NAME          JOB_KEY                           
---------------  -------  ----------------  --------------------------------  
1                0        addPeopleDescJob  d41d8cd98f00b204e9800998ecf8427e

JOB_EXECUTION_ID  JOB_INSTANCE_ID  CREATE_TIME          
----------------  ---------------  -------------------  
1                 1                2014-11-14 12:33:12  
2                 1                2014-11-14 12:33:48

查看step运行信息：

select STEP_EXECUTION_ID , STEP_NAME , JOB_EXECUTION_ID from batch_step_execution;

STEP_EXECUTION_ID  STEP_NAME    JOB_EXECUTION_ID  
-----------------  -----------  ----------------  
1                  addDescStep  1                 
2                  addDescStep  2

相应的数据库也会多出一倍的数据。

当第三次运行job时，报如下异常信息：

Caused by: org.springframework.batch.core.StartLimitExceededException: Maximum start limit exceeded for step: addDescStepStartMax: 2

很明显，就是重启的次数以用尽。。。

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