hu.webhejj.commons.io.table.excel.ExcelUtils.java Source code

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Here is the source code for hu.webhejj.commons.io.table.excel.ExcelUtils.java

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/*
 *  Copyright Gergely Nagy <greg@webhejj.hu>
 *
 *  Licensed under the Apache License, Version 2.0; 
 *  you may obtain a copy of the License at:
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 */
package hu.webhejj.commons.io.table.excel;

import hu.webhejj.commons.io.RuntimeIOException;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

/**
 * Utility methods for working with Excel
 */
public class ExcelUtils {

    public static void ensureSheet(Workbook workbook, int index) {
        for (int i = workbook.getNumberOfSheets(); i <= index; i++) {
            workbook.createSheet();
        }
    }

    public static Workbook openWorkbook(File file) {
        try {
            return openWorkbook(new FileInputStream(file));
        } catch (IOException e) {
            throw new RuntimeIOException("Error while reading excel file " + file, e);
        }
    }

    public static Workbook openWorkbook(InputStream is) {
        Workbook workbook = null;
        if (is == null) {
            workbook = new HSSFWorkbook();
        } else {
            BufferedInputStream bis = new BufferedInputStream(is);
            // read OLE magic
            bis.mark(8);
            try {
                if (bis.read() == 0xD0 && bis.read() == 0xCF && bis.read() == 0x11 && bis.read() == 0xE0
                        && bis.read() == 0xA1 && bis.read() == 0xB1 && bis.read() == 0x1A && bis.read() == 0xE1) {
                    bis.reset();
                    workbook = new HSSFWorkbook(bis);
                } else {
                    bis.reset();
                    workbook = new XSSFWorkbook(bis);
                }
            } catch (IOException e) {
                throw new RuntimeIOException("Error while reading excel input stream", e);
            }
        }
        return workbook;
    }
}