How to create custom item reader in spring batch

Question

In my app I am using sqlProcessor as database framework: https://github.com/hudec/sql-processor/wiki.

so when I want to read list of object I call:

List<MyClass> myClassList = myClassDao.list(...)

How should I iterate over this list in itemReader or how should I create my custom item reader which read data from database using sqlProcessor

Answer 1

Use an ItemReaderAdapter.
From Javadoc:
Invokes a custom method on a delegate plain old Java object which itself provides an item.

<bean id="itemReader" class="org.springframework.batch.item.adapter.ItemReaderAdapter">
    <property name="targetObject" ref="myClassDao" />
    <property name="targetMethod" value="list" />
    <property name="arguments">
      <list>
        <!-- add arguments list -->
      </list>
    </property>
</bean>

<bean id="myClassDao" class="path.to.MyClassDAO" /

If you have special condition, arguments and other needs you can create your own ItemReader, but you can extends ItemReaderAdapter to reuse your DAO and save time.