POI Excel 가 져 오기 내 보 내기

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.io.FilenameUtils;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellValue;
import org.apache.poi.ss.usermodel.DateUtil;
import org.apache.poi.ss.usermodel.FormulaEvaluator;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

/** 
 * Excel   
 *  
 * @author Snowolf 
 * @version 1.0 
 * @since 1.0 
 */   
public abstract class ExcelRead {  

    /** 
     * Excel 2003 
     */  
    private final static String XLS = "xls";  
    /** 
     * Excel 2007 
     */  
    private final static String XLSX = "xlsx";  
    /** 
     *         
     */  
    private final static String SEPARATOR = "|";  

    /** 
     *  Excel   Sheet   List 
     *  
     * @param file 
     * @param sheetNum 
     * @return 
     */   
    public static List exportListFromExcel(File file, int sheetNum)  
            throws IOException {  
        return exportListFromExcel(new FileInputStream(file),  
                FilenameUtils.getExtension(file.getName()), sheetNum);  
    }  

    /** 
     *  Excel  Sheet   List 
     *  
     * @param is 
     * @param extensionName 
     * @param sheetNum 
     * @return 
     * @throws IOException 
     */    
    public static List exportListFromExcel(InputStream is,  
            String extensionName, int sheetNum) throws IOException {  

        Workbook workbook = null;  

        if (extensionName.toLowerCase().equals(XLS)) {  
            workbook = new HSSFWorkbook(is);  
        } else if (extensionName.toLowerCase().equals(XLSX)) {  
            workbook = new XSSFWorkbook(is);  
        }  

        return exportListFromExcel(workbook, sheetNum);  
    }  

    /** 
     *     Sheet   List 
     *  
     * @param workbook 
     * @param sheetNum 
     * @return 
     * @throws IOException 
     */   
    private static List exportListFromExcel(Workbook workbook,  
            int sheetNum) {  

        Sheet sheet = workbook.getSheetAt(sheetNum);  

        //         
        FormulaEvaluator evaluator = workbook.getCreationHelper()  
                .createFormulaEvaluator();  

        List list = new ArrayList();  

        int minRowIx = sheet.getFirstRowNum();  
        int maxRowIx = sheet.getLastRowNum(); 
      //   
        for (int rowIx = minRowIx; rowIx <= maxRowIx; rowIx++) {  
            Row row = sheet.getRow(rowIx);  
            StringBuilder sb = new StringBuilder();  

            short minColIx = row.getFirstCellNum();  
            short maxColIx = row.getLastCellNum();  
          //     
            for (short colIx = minColIx; colIx <= maxColIx; colIx++) {  
            	Object[] objects = new Object[]{maxColIx};
                Cell cell = row.getCell(new Integer(colIx));  
                CellValue cellValue = evaluator.evaluate(cell);  
                if (cellValue == null) {  
                    continue;  
                }  
             //       ，     Boolean、Numeric String      ，    Error   
                //       ，      ，      http://poi.apache.org/spreadsheet/eval.html    
                switch (cellValue.getCellType()) {  
                case Cell.CELL_TYPE_BOOLEAN:  
                    sb.append(SEPARATOR+cellValue.getBooleanValue())  ;
                    break;  
                case Cell.CELL_TYPE_NUMERIC:  
                	//                 ，           
                    if (DateUtil.isCellDateFormatted(cell)) {  
                    	sb.append(SEPARATOR + cell.getDateCellValue());  
                    } else {  
                    	sb.append(SEPARATOR + cellValue.getNumberValue()); 
                    }  
                    break;  
                case Cell.CELL_TYPE_STRING:  
                	sb.append(SEPARATOR + cellValue.getStringValue());  
                    break;  
                case Cell.CELL_TYPE_FORMULA:  
                    break;  
                case Cell.CELL_TYPE_BLANK:  
                    break;  
                case Cell.CELL_TYPE_ERROR:  
                    break;  
                default:  
                    break;  
                }  
            }  
            list.add(sb.toString());  
        }  
        return list;  
    }  
}