Báo cáo được tạo dễ dàng với Excel, XML và các công nghệ Java, Phần 1

class objectName = new class();

import java.io.FileInputStream;
import java.io.IOException;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public static void main(String[] args) {
 // Create a FileInputStream to hold the file.
 // Use double back-slashes to create one "escaped" slash.
 // Use error handling (try/catch) around its creation in case
 // the file to read does not exist.
 // Be sure to import java.io.FileNotFoundException and java.io.IOException, or use 
 // the superclass IOException to handle both. 

 try {
    FileInputStream excelFIS = new FileInputStream("C:\\Planet Power\\Employee_List.xls");

    // Create an Excel Workbook Object using the FileInputStream created above
    // (which contains the file).
    // Use error handling around its creation in case of Input/Output Exception

    HSSFWorkbook excelWB = new HSSFWorkbook(excelFIS);

 }
 catch (IOException e) {
    System.out.println("Input/Output Exception!");
 }

//End Main Method
}

      // Start by getting the Spreadsheet (Excel books can have several 
      // sheets). Assuming there is just one sheet, it's the zero sheet.

      HSSFSheet topSheet = excelWB.getSheetAt(0); 

      // getRow() returns an HSSFRow object, but the numbering
      // system is logical, not physical, and zero based.
      // for example, use getRow(2) to get the third row.

      HSSFRow thirdRow = topSheet.getRow(2);

      // Get the first two cells in the row
      HSSFCell lastnameCell = thirdRow.getCell(0);
      HSSFCell firstnameCell = thirdRow.getCell(1);

      // Get the string information in the cells
      String firstName = firstnameCell.getStringCellValue();
      String lastName = lastnameCell.getStringCellValue();

      // Print out the value of the cells
      System.out.println(firstName + " " + lastName);

// Traverse the sheets by looping through sheets, rows, and cells.
// Remember, excelWB is the workbook object obtained earlier.
// Outer Loop: Loop through each sheet

for (int sheetNumber = 0; sheetNumber < excelWB.getNumberOfSheets(); sheetNumber++) {
   HSSFSheet oneSheet = excelWB.getSheetAt(sheetNumber);

// Now get the number of rows in the sheet
   int rows = oneSheet.getPhysicalNumberOfRows();

   // Middle Loop: Loop through rows in the sheet

   for (int rowNumber = 0; rowNumber < rows; rowNumber++) {
      HSSFRow oneRow = oneSheet.getRow(rowNumber);

      // Skip empty (null) rows.
      if (oneRow == null) {
         continue;
      }

      // Get the number of cells in the row
      int cells = oneRow.getPhysicalNumberOfCells();

      // Inner Loop: Loop through each cell in the row

      for (int cellNumber = 0; cellNumber < cells; cellNumber++) {
         HSSFCell oneCell = oneRow.getCell(cellNumber);

         // Get the value of the string in the cell.
         // Print out the String value of the Cell 
         // This section will result in an error. Why?

         String cellValue = oneCell.getStringCellValue(); 
          System.out.println(cellValue + ", ");

      // End Inner Loop
      }
   // End Middle Loop
   }
// End Outer Loop
}

      // Inner Loop: Loop through each cell in the row

      for (int cellNumber = 0; cellNumber < cells; cellNumber++) {
         HSSFCell oneCell = oneRow.getCell(cellNumber);

         // Test the value of the cell.
         // Based on the value type, use the proper 
         // method for working with the value.

         // If the cell is blank, the cell object is null, so don't 
         // try to use it. It will cause errors.
         // Use continue to skip it and just keep going.

        if (oneCell == null) {
            continue;
         }

         switch (oneCell.getCellType()) {

         case HSSFCell.CELL_TYPE_STRING:
            System.out.println(oneCell.getStringCellValue());
            break;

         case HSSFCell.CELL_TYPE_FORMULA:
            System.out.println(oneCell.getCellFormula());
            break;

         case HSSFCell.CELL_TYPE_NUMERIC:
            System.out.println(oneCell.getNumericCellValue());
            break;

         case HSSFCell.CELL_TYPE_ERROR:
            System.out.println("Error!");
            break;
         } 

      // End Inner Loop
      }

// If the cell is blank, the cell object is null, so don't 
// try to use it. It will cause errors.
// Use continue to skip it and just keep going.

if (oneCell == null) {
   continue;
}