我需要使用Apache POI在Excel工作表中迭代到Java列的末尾

我正在迭代一列值，直到遇到空白。 我需要收集整个专栏并存储它，没有其他值。 我试图检查空白，null，0，“”和CELL_TYPE_BLANK（int = 3），我不能得到它来避免空指针exception。 代码片段和错误如下。 我能做什么？ 这不是整个方法或程序，只是相关的一块。

String s = list[i]; //find the directory from the list array to locate the file InputStream input = new FileInputStream(s); //create a new workbook object to hold the excel file Workbook wb = new XSSFWorkbook(input); //create an arbitrary starting location int column = 2; //absolutely the correct number int rownum = 10; //get the value from the first sheet org.apache.poi.ss.usermodel.Sheet insheet = wb.getSheetAt(0); //of the second columm Row row = insheet.getRow(rownum); //in the 11th row (arbitrary number used to reduce iterations and skip whitespace) Cell cell = row.getCell(column); System.out.println("Skimming sheet: " + insheet.getSheetName()); //iterate until the very end of the column is found System.out.println("Cell value B" + (rownum-1) + ": " + cell); //3 denotes CELL_TYPE_BLANK while (cell.getCellType() != 3 ) { //go to the next location //update to the next cell System.out.println("Cell value B" + rownum + ": " + cell); row = insheet.getRow(rownum); if(row.getCell(column).getCellType() != 3){ cell = row.getCell(column); //error occurs here, line 241 } rownum++; } Exception in thread "main" java.lang.NullPointerException at FileTest.skim(FileTest.java:241) at FileTest.main(FileTest.java:121) 

Answer 1

你得到错误，因为你试图访问的行是空的，而不是单元格。 你想看一下Apache POI Iterator的例子。

 //taken from the example Sheet sheet = wb.getsheetat(0); for (Iterator<Row> rit = sheet.rowiterator(); rit.hasnext(); ) { Row row = rit.next(); //now, based in your needs Cell cell = row.getCell(column); //do what you need with the row-column } 

Answer 2

迭代循环中的行到最后一行，这将防止运行到该exception：

  for(int i =0 ; i< insheet.getLastRowNum(); i++){ //do stuff }