Programming and So

Spring Batch provides a framework in order to develop batch processes in Java. Recently version 2.0 has been released. However it’s still hard to find good samples and resources in the web, so old-fashioned development (based on RTFM) must be performed.

The main idea is to build Jobs from sequential steps. Each step can be a single task or an input/output process. Following Spring philosophy, configuration can be done using XML.

At least, two XML files must be defined:

• Launch context. Job launcher, datasources and other usual Spring resources.
• Job definition. Jobs and Spring beans implementing tasks.

A batch can be launched from command line using CommandLineJobLauncher class provided by the framework. The argument “job” indicates job name and some other job parameters can be added using “key=value” pattern.

java CommandLineJobRunner job-definition.xml job date=2008/01/01

Below a basic sample  (read web server log file and insert processed lines to database) is exposed.

Launch context (job-definition.xml)

< ?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
  xmlns:p="http://www.springframework.org/schema/p" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
    http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

  <import resource="classpath:module-context.xml"/>

  <!-- In memory JOB Management -->
  <bean id="jobLauncher" class="es.lacaixa.premia.batch.launcher.StatisticsBatchLauncher">
<property name="jobRepository" ref="jobRepository" />
  </bean>

  <bean id="jobRepository" class="org.springframework.batch.core.repository.support.MapJobRepositoryFactoryBean">
<property name="transactionManager" ref="transactionManager"/>
  </bean>

  <bean id="transactionManager" class="org.springframework.batch.support.transaction.ResourcelessTransactionManager" />

  <!-- Datasource -->
  <bean id="dataSource" class="org.springframework.jdbc.datasource.SingleConnectionDataSource">
<property name="driverClassName" value="${jdbc.driver}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
  </bean>

  <bean id="transactionManagerAccess" class="org.springframework.jdbc.datasource.DataSourceTransactionManager" lazy-init="true">
<property name="dataSource" ref="dataSource" />
  </bean>

</beans>

Job definition (module-context.xml)

< ?xml version="1.0" encoding="UTF-8"?>
<beans :beans xmlns="http://www.springframework.org/schema/batch"
  xmlns:beans="http://www.springframework.org/schema/beans"
  xmlns:aop="http://www.springframework.org/schema/aop"
  xmlns:tx="http://www.springframework.org/schema/tx"
  xmlns:p="http://www.springframework.org/schema/p"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
          http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
          http://www.springframework.org/schema/batch
          http://www.springframework.org/schema/batch/spring-batch-2.0.xsd
          http://www.springframework.org/schema/aop
      http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">

  <job id="job" job-repository="jobRepository">
    <step id="stepWSLogFiles">
        <tasklet>
            <chunk processor="wsLogToDbTransform"
                       reader="flatFileWSItemReader"
                       writer="localDBItemWriter" commit-interval="100" />
        </tasklet>
    </step>
  </job>

  </beans><beans :bean id="localDbItemWriter" class="com.foo.PeticionDao">
    <beans :property name="dataSource" ref="dataSource" />
  </beans>

  <beans :bean id="flatFileWSItemReader" class="org.springframework.batch.item.file.FlatFileItemReader">
    <beans :property name="resource" value="${webserver.file}*" />
    </beans><beans :property name="lineMapper">
      </beans><beans :bean class="org.springframework.batch.item.file.mapping.DefaultLineMapper">
        </beans><beans :property name="lineTokenizer">
          </beans><beans :bean class="org.springframework.batch.item.file.transform.DelimitedLineTokenizer">
            <beans :property name="delimiter" value=";" />
            <beans :property name="names" value="date,hora,tm" />
          </beans>

        <beans :property name="fieldSetMapper">
          </beans><beans :bean class="org.springframework.batch.item.file.mapping.BeanWrapperFieldSetMapper">
            <beans :property name="targetType" value="com.foo.FileLogWS" />
          </beans>

  <beans :bean id="wsLogToDbTransform" class="com.foo.WSLogToDbTransform" />