Apache POI和Null指针…csv转换为xlsx

Question

I am using Apache poi to parse through Excel 2010 files. I have a csv file that has the same content as one of my excel files. I opened my csv file in excel and saved it as an Excel workbook thinking that it should work in the program that I wrote but I keep getting null pointer exceptions. These happen on the lines of code that look up cells in the file when given a row number and a column number. I havent been able to find the cause for these null pointers and it works completely fine on my regular excel file. Is it just that the file was previously a csv file?

I am using the XSSF Usermodel

This is where it fails

RPCManager rpc = new RPCManager(
    sheet.getRow(row).getCell(indexes.name).toString(), 
    sheet.getRow(row).getCell(indexes.status).toString(), 
    sheet.getRow(row).getCell(indexes.customer).toString(), 
    sheet.getRow(row).getCell(indexes.site).toString(), 
    sheet.getRow(row).getCell(indexes.suite).toString(), 
    sheet.getRow(row).getCell(indexes.pod).toString(), 
    sheet.getRow(row).getCell(indexes.amps).toString(), 
    sheet.getRow(row).getCell(indexes.pp1).toString(), 
 ** sheet.getRow(row).getCell(indexes.pp2).toString(), **
    sheet.getRow(row).getCell(indexes.pp3).toString(), 
    sheet.getRow(row).getCell(indexes.cab).toString(), 
    sheet.getRow(row).getCell(indexes.rpcNum).toString(), 
    sheet.getRow(row).getCell(indexes.rpcPan).toString(), 
    sheet.getRow(row).getCell(indexes.rpcBr).toString(), 
    row);

"indexes.whatever" is just the index of the column and row is the row

This is a small part of the program that takes information in an excel file and writes an XML file. The Excel file has 2500-3000 rows and spits out around 70 XML files. The code above saves the needed information from the excel file to a class. This part of code is called around 2500 times. I'm guessing it broke on its first time around. It only gives the null pointer exception and the location where it happened which is on the line with the asterisks above.

Sorry I am kind of new to programming so I am pretty clueless

Answer 1

The null pointers occur because there is nothing in the worksheet at that row/column location. You need to explicitly verify that there's a cell there before trying to fetch it.

What you do if a cell is null depends totally on how RPCManager handles missing data. If it can cope with nulls then something like the following might work:

int[]    cellNums = {indexes.name, indexes.status, ... ,indexes.rpcBr};
String[] cellVals = new String[cellNums.length];
XSSFRow r = sheet.getRow(row);
for (int i=0; i<cellNums; i++)
{
    XSSFCell c = r.getCell(cellNums[i]);
    cellVals[i] = c == null ? null : c.toString();
}
RPCManager rpc = new RPCManager(
    cellVals[0],
    cellVals[1],
    ...
    cellVals[13],
    row);

Otherwise you'll have to decide what to do when there is missing data.