Question

我在打下一列价值,直到打上空白。我需要收集整个一栏并储存该栏,而没有其他价值。我曾试图对空白、无效、0、“”和CELL_TYPE_BLANK(int = 3)进行核对,因此我无法回避一个无效的例外。法典的刀切和错误如下。我能做些什么? 这并不是整个方法或方案,只是相关内容。

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

你再次发现这一错误,因为你试图进入的行子是无效的,而不是牢房。请参看Apache POI Iterator。

//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

预留一行,以至最后一行,这将防止该例外情况发生:

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

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