In this program we are going to explain about POI API Event.
POI API Event
In this program we are going to explain about POI API
Event.
The advantage of
event API is that you can read an XLS with a relatively small memory.
To use Event API we construct an instance of org.apache.poi.hssf.eventmodel.HSSFRequest.
To register a class we have to create listener org.apache.poi.hssf.eventmodel.HSSFListener
interface and use HSSFRequest.addListener(yourlistener, recordsid) method.
The record Sid should be a static reference number (such as BOFRecord.sid)
contained in the classes in org.apache.poi.hssf.record. Alternatively you
can call HSSFRequest.addListenerForAllRecords(mylistener).
Once we have registered our listeners in the HSSFRequest
object we can construct an instance of org.apache.poi.poifs.filesystem.FileSystem
and pass it your XLS file inputstream. We can either pass this, along with
the request we constructed, to an instance of HSSFEventFactory via the HSSFEventFactory.processWorkbookEvents(request,
Filesystem) method, or we can get an instance of DocumentInputStream from
Filesystem.createDocumentInputStream("Workbook") and pass it to
HSSFEventFactory.processEvents(request, inputStream). Once we make this
call, the listeners that we constructed receive calls to their processRecord(Record)
methods with each Record they are registered to listen for until the file has
been completely read.
The code of the program is given below:
import java.io.*;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.poifs.filesystem.*;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.eventusermodel.*;
import org.apache.poi.hssf.record.*;
import org.apache.poi.hssf.dev.EFHSSF;
public class EventAPIsExample implements HSSFListener
{
public static void main(String[] args) throws IOException
{
FileInputStream fin = new FileInputStream("example.xls");
POIFSFileSystem poifs = new POIFSFileSystem(fin);
InputStream din = poifs.createDocumentInputStream
("Workbook");
HSSFRequest req = new HSSFRequest();
req.addListenerForAllRecords(new EventAPIsExample());
HSSFEventFactory factory = new HSSFEventFactory();
System.out.println("\n\nExample of Event
API using POI3.0)\n\n");
factory.processEvents(req, din);
fin.close();
din.close();
System.out.println("\n\nIn main method ->>
public static void main(String[] args)");
}
public void processRecord(Record record)
{
System.out.println("In Processs method ->>
public void processRecord(Record record)");
}
}
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The output of the program is given below:
| C:\POI3.0\exmples\execl>javac
EventAPIsExample.java
C:\POI3.0\exmples\execl>java
EventAPIsExample example.xls
Example of Event API using POI3.0)
In Processs method ->>public void
processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In Processs method ->>public void processRecord(Record record)
In main method ->>public static void
main(String[] args)
C:\POI3.0\exmples\execl>
|
Download this example.
