Spring batch job csv file read recover from the line where it failed

问题

The reader looks like this,

<bean id="cvsFileItemReader" class="org.springframework.batch.item.file.FlatFileItemReader" scope="step">

    <property name="resource" value="classpath:cvs/input/report.csv" />
    <property name="lineMapper">
        <bean class="org.springframework.batch.item.file.mapping.DefaultLineMapper">
            <property name="lineTokenizer">
                <bean
                    class="org.springframework.batch.item.file.transform.DelimitedLineTokenizer">
                    <property name="names" value="id,impressions" />
                </bean>
            </property>
            <property name="fieldSetMapper">
                <bean
                    class="org.springframework.batch.item.file.mapping.BeanWrapperFieldSetMapper">
                    <property name="prototypeBeanName" value="report" />
                </bean>
            </property>
        </bean>
    </property>

</bean>

What I want to achieve is, if while reading the CSV file, the reader/job fails, then the next scheduled jobinstance should start the reader from the line it failed in last jobexecution. I can keep track of lines processed by a counter in the CustomProcessor process() function.

But any idea how to read the csv file from the last execution's failed state?

I want to manually launch/restart the failed job. Should I implement SkipPolicy as described here http://thisisurl.com/spring-batch-skip-and-retry?

(CSV file can be a big DB as well, but for now I am testing this scenario on CSV file)

回答1:

If your application fails, you can use folowing:

But any idea how to read the csv file from the last execution's failed state?

Add it to jobParameters they saved in batch table batch_job_execution_params.

At application start up find incomplete jobs in batch_job_execution and restart in manualy.

I want to manually launch/restart the failed job. Should I implement SkipPolicy as described here http://thisisurl.com/spring-batch-skip-and-retry?

I think this is not necessary, for restartability.

If you want restart some lines in your csv, just use RetryPolicy:

    <batch:step id="processing-step">
        <batch:tasklet>
            <batch:chunk reader="csv_reader"
                         processor="csv_processor"
                         writer="csv_writer"
                         commit-interval="5">
                <batch:retry-policy>
                    <bean class="org.springframework.retry.policy.AlwaysRetryPolicy" scope="step"/>
                </batch:retry-policy>
            </batch:chunk>
        </batch:tasklet>
    </batch:step>

Spring Batch automatically handle failed chunks (chunks, in which throws an exception). Documentation.

来源：https://stackoverflow.com/questions/21451934/spring-batch-job-csv-file-read-recover-from-the-line-where-it-failed