Java-从excel中删除重复项

我发现这个代码在线，并尝试运行它。 但它是给和空指针错误。 谁能帮助解决这个问题吗？ 谢谢

错误是说：java.lang.NullPointerException在LearnJava.compareText.main（compareText.java:79）

package test; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.util.ArrayList; import java.util.Arrays; import java.util.HashSet; import java.util.Iterator; import java.util.List; import java.util.Set; 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; import org.apache.poi.poifs.filesystem.POIFSFileSystem; import org.apache.poi.ss.usermodel.Cell; public class Removeduplicate { public static void main(String[] args) { HSSFWorkbook workbook_Output; HSSFWorkbook workbook_Output_Dup; HSSFWorkbook workbook_Output_Final; HSSFWorkbook workbook_Output_Final_2=null; HSSFSheet sheet_Output; HSSFSheet sheet_Output_Dup; HSSFSheet sheet_Output_Final; HSSFRow row_Output; HSSFRow row_Output_Dup; HSSFRow row_Output_Final; HSSFCell cell; HSSFRow row_Output_dup; // Set<Integer> markrowdup = new HashSet<Integer>(); //List<HSSFCell> cellStoreList=new ArrayList<HSSFCell>(); try { FileInputStream fistream_Output= new FileInputStream("C:\\Users\\Satya\\Desktop\\Output.xls"); workbook_Output = new HSSFWorkbook(new POIFSFileSystem(fistream_Output)); File file_dup = new File("C:\\Users\\Satya\\Desktop\\Output_Dup.xls"); FileOutputStream fistream_output_dup = new FileOutputStream(file_dup); workbook_Output.write(fistream_output_dup); fistream_output_dup.close(); FileInputStream fistream_Output_Dup= new FileInputStream("C:\\Users\\Satya\\Desktop\\Output_Dup.xls"); workbook_Output_Dup = new HSSFWorkbook(fistream_Output_Dup); //File file_final_2 = new File("C:\\Users\\Satya\\Desktop\\Output_CRQ.xls"); for (int sheetnum = 0; sheetnum < workbook_Output.getNumberOfSheets(); sheetnum++) { Set<Integer> markrowdup = new HashSet<Integer>(); List<HSSFCell> cellStoreList=new ArrayList<HSSFCell>(); sheet_Output_Dup = workbook_Output_Dup.getSheetAt(sheetnum); sheet_Output = workbook_Output.getSheetAt(sheetnum); int lastrow = sheet_Output.getLastRowNum(); for (int i = 1; i <= lastrow; i++) { row_Output_Dup = sheet_Output_Dup.getRow(i); row_Output = sheet_Output.getRow(i); for (int j = i; j <= lastrow; j++) { row_Output_dup = sheet_Output.getRow(j); if(i!=j) { if(row_Output.getCell(1).getStringCellValue()==row_Output_dup.getCell(1).getStringCellValue()) { markrowdup.add(j); System.out.println(row_Output.getCell(1).getStringCellValue()+" : Duplicte row num: "+j); } } } } Object[] o = markrowdup.toArray(); Arrays.sort(o); for (Object object : o) { int row = ((Integer) object).intValue(); row_Output_Dup=sheet_Output_Dup.getRow(row); sheet_Output_Dup.removeRow(row_Output_Dup); } File file_final = new File("C:\\Users\\Satya\\Desktop\\Output_Final.xls"); FileOutputStream fostream_final = new FileOutputStream(file_final); workbook_Output_Dup.write(fostream_final); fostream_final.close(); FileInputStream fistream_final = new FileInputStream(file_final); workbook_Output_Final = new HSSFWorkbook(fistream_final); sheet_Output_Final = workbook_Output_Final.getSheetAt(sheetnum); for (int i = 0; i <= sheet_Output_Final.getLastRowNum(); i++) { row_Output_Final = sheet_Output_Final.getRow(i); if(row_Output_Final==null) System.out.println("Row is null"); else { Iterator<Cell> iterator_output_final = row_Output_Final.cellIterator(); while (iterator_output_final.hasNext()) { cell = (HSSFCell) iterator_output_final.next(); cellStoreList.add(cell); } } } Iterator<HSSFCell> iterator_final_data = cellStoreList.iterator(); File file_final_2 = new File("C:\\Users\\Satya\\Desktop\\Output_CRQ.xls"); FileOutputStream fostream_final_2 = new FileOutputStream(file_final_2); if(workbook_Output_Final_2 == null) workbook_Output_Final_2=new HSSFWorkbook(); workbook_Output_Final_2.createSheet(workbook_Output.getSheetName(sheetnum)); HSSFSheet temp = workbook_Output_Final_2.getSheetAt(sheetnum); int i=0; int temp_row=0; HSSFRow row = temp.createRow(temp_row); while (iterator_final_data.hasNext()) { HSSFCell cell2 = iterator_final_data.next(); row.createCell(i).setCellValue(cell2.getStringCellValue()); System.out.print(cell2.getStringCellValue()+": :"); i++; if(i==4) { System.out.println(); i=0; temp_row++; row = temp.createRow(temp_row); } } workbook_Output_Final_2.write(fostream_final_2); //fostream_final_2.close(); fistream_final.close(); fistream_Output.close(); fostream_final_2.flush(); fostream_final_2.close(); } fistream_Output.close(); fistream_Output_Dup.close(); } catch (Exception e) { e.printStackTrace(); } } } 

感谢您的帮助。 非常感谢