Spring 批处理具有读取复杂文件的能力。唯一的问题是我们必须编写自己的阅读器来处理复杂文件。任何具有特定模式的文件我们都可以通过 spring Batch 读取。

这是像你的文件的文件格式

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

自定义 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.PException;
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,
PException {
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);
}
}

配置

    <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"/>

输出写入器

<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>

输出将是

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;
}
}