Thread: Apache POI

First off I feel that I should state that I am very much a Java novice. For my research I am modifying a very extensive code in order to optimize aspects of the data analysis process. In order to do this I need to export the data generated in the java code to an excel document where I can then arrange and display the data along with a few other calculations. I've referenced the internet and decided to use Apache POI 3.7 to export the data. As of now I just have written some very simple code in an example project just to get a feel for the POI. However I'm getting syntax errors with the last two lines of my code which I assume is relatively easy to fix.

import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;

import java.io.FileOutputStream;
import java.io.File;
import java.io.IOException;

public class Example {

Workbook wb = new HSSFWorkbook();
//Workbook wb = new XSSFWorkbook();
Sheet sheet1 = wb.createSheet("new sheet");
FileOutputStream fileOut = new FileOutputStream("workbook.xls");
wb.write(fileOut);
fileOut.close();

}

Also, in the future when I am looking to export my data I assume my data will be stored as some string but I wasn't sure if the data has to be stored or labeled in the java program in order to effectively be exported to Excel.

Sorry for not posting the entire error in the first post but here is the message in its entirety: "Syntax error on token "fileOut", VariableDeclaratorld expected after this token".

I've now altered my code and it seems to be written with no errors however when I try to run the code I receive the error from Eclipse "Launch configuration ExcelExtractor references non-existing project TestPOI." Any help with this error would be greatly appreciated.

This code that I've written is merely a test run through with the API and will most definitely need to be extended but so far all I've created is a new java project containing one class file. The following code is all the public class file contains:

import org.apache.poi.hssf.usermodel.*;
import java.io.FileOutputStream;
import java.io.File;
import java.io.IOException;

public class Example {

HSSFWorkbook workbook = new HSSFWorkbook();
HSSFSheet firstsheet = workbook.createSheet("Data 1");

FileOutputStream fos=null; {
try{
fos = new FileOutputStream(new File("Data.xls"));
workbook.write(fos);
}catch(IOException e){
e.printStackTrace();
}finally{
if (fos!=null){
try{
fos.flush();
fos.close();
}catch(IOException e){
e.printStackTrace();
}
}
}
}
}
To execute this program I have simply been trying to run the class file and the project from Eclipse and am receiving the previously stated "ExcelExtractor" error. Am I trying to execute the program incorrectly?

I added a main method to the class file but I am still receiving the same error as before, "Launch configuration ExcelExtractor references non-existing project TestPOI."

Here is what I have written so far:

import org.apache.poi.hssf.usermodel.*;
import java.io.FileOutputStream;
import java.io.File;
import java.io.IOException;
 
class Example {
	public static void main(String[] args) {
HSSFWorkbook workbook = new HSSFWorkbook();
 
FileOutputStream fos=null; {
try{
	fos = new FileOutputStream(new File("Data.xls"));
	workbook.write(fos);
}catch(IOException e){
	e.printStackTrace();
}finally{
	if (fos!=null){
		try{
			fos.flush();
			fos.close();
		}catch(IOException e){
			e.printStackTrace();
		}
		}
	}
}
}}

Just out of curiosity I booted into windows 7 and ran the same code I posted above in eclipse and did not receive the error I had previously posted about. However, although the Excel file was written, upon opening the file an error is displayed as follows " File error: data may have been lost." I wasn't too concerned because my original code didn't contain any data to transfer but when putting in some basic data to transfer I still am receiving the same error and no data is being displayed in the excel document. Any suggestions on how to overcome this would be greatly appreciated.