Spring batch have the capability of reading complex files. only thing is we have to write our own readers to process complex files.any file having particular pattern we can read it through spring Batch.
this is file format like your file
CUST,Warren,Q,Darrow,8272 4th Street,New York,IL,76091
TRANS,1165965,2011-01-22 00:13:29,51.43
CUST,Ann,V,Gates,9247 Infinite Loop Drive,Hollywood,NE,37612
CUST,Erica,I,Jobs,8875 Farnam Street,Aurora,IL,36314
TRANS,8116369,2011-01-21 20:40:52,-14.83
TRANS,8116369,2011-01-21 15:50:17,-45.45
TRANS,8116369,2011-01-21 16:52:46,-74.6
TRANS,8116369,2011-01-22 13:51:05,48.55
TRANS,8116369,2011-01-21 16:51:59,98.53
Custom FileReader
import Java.util.ArrayList;
import org.springframework.batch.item.ExecutionContext;
import org.springframework.batch.item.ItemStreamException;
import org.springframework.batch.item.ItemStreamReader;
import org.springframework.batch.item.ParseException;
import org.springframework.batch.item.UnexpectedInputException;
public class CustomerFileReader implements ItemStreamReader<Object> {
private Object curItem = null;
private ItemStreamReader<Object> delegate;
public Object read() throws Exception {
if(curItem == null) {
curItem = (Customer) delegate.read();
}
Customer item = (Customer) curItem;
curItem = null;
if(item != null) {
item.setTransactions(new ArrayList<Transaction>());
while(peek() instanceof Transaction) {
curItem = null;
}
}
return item;
}
public Object peek() throws Exception, UnexpectedInputException,
ParseException {
if (curItem == null) {
curItem = delegate.read();
}
return curItem;
}
public void setDelegate(ItemStreamReader<Object> delegate) {
this.delegate = delegate;
}
public void close() throws ItemStreamException {
delegate.close();
}
public void open(ExecutionContext arg0) throws ItemStreamException {
delegate.open(arg0);
}
public void update(ExecutionContext arg0) throws ItemStreamException {
delegate.update(arg0);
}
}
Configuration
<beans:bean id="customerFile"
class="org.springframework.core.io.FileSystemResyource" scope="step">
<beans:constructor-arg value="#{jobParameters[customerFile]}"/>
</beans:bean>
<beans:bean id="customerFileReader"
class="com.apress.springbatch.chapter7.CustomerFileReader">
<beans:property name="delegate" ref="trueCustomerFileReader"/>
</beans:bean>
<beans:bean id="trueCustomerFileReader"
class="org.springframework.batch.item.file.FlatFileItemReader">
<beans:property name="resource" ref="customerFile" />
<beans:property name="lineMapper">
<beans:bean class="org.springframework.batch.item.file.mapping.
PatternMatchingCompositeLineMapper">
<beans:property name="tokenizers">
<beans:map>
<beans:entry key="CUST*" value-ref="customerLineTokenizer"/>
<beans:entry key="TRANS*" value-ref="transactionLineTokenizer"/>
</beans:map>
</beans:property>
<beans:property name="fieldSetMappers">
<beans:map>
<beans:entry key="CUST*" value-ref="customerFieldSetMapper"/>
<beans:entry key="TRANS*" value-ref="transactionFieldSetMapper"/>
</beans:map>
</beans:property>
</beans:bean>
</beans:property>
</beans:bean>
<beans:bean id="customerLineTokenizer"
class="org.springframework.batch.item.file.transform.
DelimitedLineTokenizer">
<beans:property name="names" value="prefix,firstName,middleInitial,
lastName,address,city,state,zip"/>
<beans:property name="delimiter" value=","/>
</beans:bean>
<beans:bean id="transactionLineTokenizer"
class="org.springframework.batch.item.file.transform.DelimitedLineTokenizer">
<beans:property name="names"
value="prefix,accountNumber,transactionDate,amount"/>
<beans:property name="delimiter" value=","/>
</beans:bean>
<beans:bean id="customerFieldSetMapper"
class="org.springframework.batch.item.file.mapping.
BeanWrapperFieldSetMapper">
<beans:property name="prototypeBeanName" value="customer"/>
</beans:bean>
<beans:bean id="transactionFieldSetMapper"
class="com.apress.springbatch.chapter7.TransactionFieldSetMapper"/>
<beans:bean id="customer" class="com.apress.springbatch.chapter7.Customer"
scope="prototype"/>
Outpur Writer
<beans:bean id="outputFile"
class="org.springframework.core.io.FileSystemResyource" scope="step">
<beans:constructor-arg value="#{jobParameters[outputFile]}"/>
</beans:bean>
<beans:bean id="outputWriter"
class="org.springframework.batch.item.file.FlatFileItemWriter">
<beans:property name="resource" ref="outputFile" />
<beans:property name="lineAggregator">
<beans:bean class="org.springframework.batch.item.file.transform.
PassThroughLineAggregator"/>
</beans:property>
</beans:bean>
output will be
Warren Q. Darrow has 1 transactions.
Ann V. Gates has no transactions.
Erica I. Jobs has 5 transactions.
CustomerFieldSetMapper
import org.springframework.batch.item.file.mapping.FieldSetMapper;
import org.springframework.batch.item.file.transform.FieldSet;
import org.springframework.validation.BindException;
public class CustomerFieldSetMapper implements FieldSetMapper<Customer> {
public Customer mapFieldSet(FieldSet fieldSet) throws BindException {
Customer customer = new Customer();
customer.setAddress(fieldSet.readString("addressNumber") +
" " + fieldSet.readString("street"));
customer.setCity(fieldSet.readString("city"));
customer.setFirstName(fieldSet.readString("firstName"));
customer.setLastName(fieldSet.readString("lastName"));
customer.setMiddleInitial(fieldSet.readString("middleInitial"));
customer.setState(fieldSet.readString("state"));
customer.setZip(fieldSet.readString("zip"));
return customer;
}
}
