从 excel 读取时出现空指针异常？

Question

public class ExecuteTest {
@Test

public void testLogin() throws Exception {
    // TODO Auto-generated method stub
`WebDriver webdriver = new FirefoxDriver();

ReadExcelFile file = new ReadExcelFile();
ReadObject object = new ReadObject();
Properties allObjects = object.getObjectRepository();
UIOperation operation = new UIOperation(webdriver);
//Read keyword sheet
Sheet RDSheet = file.readExcel(System.getProperty("user.dir")+"\","TestCase.xlsx" , "KeywordFramework");
//Find number of rows in excel file
int rowCount =        //Loop over all the rows RDSheet.getLastRowNum()-RDSheet.getFirstRowNum();
    //Create a loop over all the rows of excel file to read it
    for (int i = 1; i < rowCount+1; i++) {
        Row row = RDSheet.getRow(i);
        //Check if the first cell contain a value, if yes, That means it is the new testcase name
    if(row.getCell(0).toString().length()==0){
        //Print testcase detail on console
        System.out.println(row.getCell(1).toString()+"----"+ row.getCell(2).toString()+"----"+
        row.getCell(3).toString()+"----"+ row.getCell(4).toString());
        //Call perform function to perform operation on UI
        operation.perform(allObjects, row.getCell(1).toString(), row.getCell(2).toString(),
                row.getCell(3).toString(), row.getCell(4).toString());
     }
else{

//Print the new testcase name when it started
            System.out.println("New Testcase->"+row.getCell(0).toString() +" Started");
            }
}
}
}

当第一个单元格为空时出现空指针异常。我搜索了很多博客但找不到任何解决方案谁能帮我写代码。

Answer 1

确保在使用 toString() 方法之前添加空检查，否则如果值为 null.

，您将得到 NPE

if (row.getCell(0) != null) {
     row.getCell(0).toString() //in this case you are trying to call toString on null value.
}

参考这个SO question

Answer 2

为每个 .toString() 添加一个 " "+ x.toString()，这样值就不会变成 null。 `

for (int i = 1; i < rowCount+1; i++) {
        Row row = RDSheet.getRow(i);
        //Check if the first cell contain a value, if yes, That means it is the new testcase name
    if((row.getCell(0)+"").toString().length()==0){
        //Print testcase detail on console
        System.out.println((row.getCell(1)+"").toString()+"----"+ (row.getCell(2)+"").toString()+"----"+
        (row.getCell(3)+"").toString()+"----"+ (row.getCell(4)+"").toString());
        //Call perform function to perform operation on UI
        //your operations
     }
else{

//Print the new testcase name when it started
            System.out.println("New Testcase->"+row.getCell(0).toString() +" Started");
            }
}


`

Answer 3

尝试下面的代码，它对我来说工作正常，我们不能定义 Null 的长度

if(row.getCell(0)==null){
            //Print testcase detail on console
//System.out.println("testing");
            System.out.println(row.getCell(1)+"----"+ row.getCell(2)+"----"+
                row.getCell(3)+"----"+ row.getCell(4));
            //Call perform function to perform operation on UI
            try{
                operation.perform(allObjects, row.getCell(1)==null?"Not a Valid KeyWord":row.getCell(1).toString(), 
                        row.getCell(2)==null?null:row.getCell(2).toString(),
                                row.getCell(3)==null?null:row.getCell(3).toString(), 
                                        row.getCell(4)==null?null:row.getCell(4).toString());
            }catch(Exception e)
            {
                //will print Error Row and break the flow
                System.out.println(i);
                System.out.println(e);
                break;
            }
     }
        else{
            //Print the new testcase name when it started
                System.out.println("New Testcase->"+row.getCell(0) +" Started");
            }
        }

从 excel 读取时出现空指针异常？

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