Bean

A bean is a type that contains methods implementing business logic. In batch, interfaces such as ItemReader, ItemProcessor, ItemWriter, and Tasklet, which are written to compose steps, have their roles during step execution predefined. Therefore, during development, the required interfaces must be implemented to develop the bean.

1. ItemReader

In a batch step, it retrieves data to be processed from resources such as DB or files and delivers it to ItemProcessor or ItemWriter.

Implemented interface

public interface org.springframework.batch.item.ItemReader

Implemented method: Responsible for reading each unit of target data from DB or files

T read() throws Exception, UnexpectedInputException, ParseException, NonTransientResourceException;

2. ItemProcessor

It processes/transforms items received from ItemReader according to business requirements and delivers them to ItemWriter.

Implemented interface

public interface org.springframework.batch.item.ItemProcessor<I, O>

Implemented method: Responsible for processing each unit of target data according to business requirements

O process(I item) throws Exception;

3. ItemWriter

It records items received from ItemReader or ItemProcessor into storage media such as DB or files.

Implemented interface

public interface org.springframework.batch.item.ItemWriter<T>

Implemented method: Responsible for recording processed result data into DB or files per commit unit, or transmitting it to external systems

void write(List<? extends T> items) throws Exception;

4. ItemStream

Before the step starts, it performs initialization to use resources such as DB or files, and after the step is completed, it performs resource cleanup and, if necessary, progress management by executing this interface.

Implemented interface

public interface org.springframework.batch.item.ItemStream

Implemented method: Initialization processing - called by the framework before the step starts

void open(ExecutionContext executionContext) throws ItemStreamException;

Implemented method: Progress state recording - called by the framework at each commit (per commit-interval)

void update(ExecutionContext executionContext) throws ItemStreamException;

Implemented method: Resource cleanup - called by the framework after the step is completed

void close() throws ItemStreamException;