How to insert a null value in Excel from Java code using ApachePOI-CodePudding

I have a one field with admissionDate in Student object, which is suppose should be null anytime When am inserting that value into the excel using apache poi i am getting NullPointerException. Data type of admissionDate is Date

Below is my code

    Row studentRow = studentSheet.createRow(0);
    studentRow.createCell(0).setCellValue("Id");
    studentRow.createCell(1).setCellValue("Name");
    studentRow.createCell(2).setCellValue("Admission_Date");
    
    int studentCount = 1;
    
    for(Student student : listOfStudent) {
        Row studentRow = accountSheet.createRow(studentCount);
        studentRow.createCell(0).setCellValue(student.getId());
        studentRow.createCell(1).setCellValue(student.getName());
        studentRow.createCell(2).setCellValue(student.getAdmissionDate());
        studentCount  ;     
    }

But when admission date is null then i have getting below exception

Exception in thread "main" java.lang.NullPointerException
    at java.util.Calendar.setTime(Calendar.java:1770)
    at org.apache.poi.ss.usermodel.DateUtil.getExcelDate(DateUtil.java:86)
    at org.apache.poi.xssf.usermodel.XSSFCell.setCellValue(XSSFCell.java:600)
    at com.wd.classes.CreateExcelFile.generateExcelFile(CreateExcelFile.java:269)

How can i insert a NULL cell if admissiondate is not available

CodePudding user response：

You should check the date before inserting it into the cell:

for(Student student : listOfStudent) {
        Row studentRow = accountSheet.createRow(studentCount);
        studentRow.createCell(0).setCellValue(student.getId());
        studentRow.createCell(1).setCellValue(student.getName());
        if( student.getAdmissionDate() != null) ) {
           studentRow.createCell(2).setCellValue(student.getAdmissionDate());
        }
        studentCount  ;     
    }

CodePudding user response：

You can set blank once you create cell something like below:

for(Student student : listOfStudent) {
        Row studentRow = accountSheet.createRow(studentCount);
        studentRow.createCell(0).setCellValue(student.getId());
        studentRow.createCell(1).setCellValue(student.getName());
    (student.getAdmissionDate() != null ? 
    studentRow.createCell(2).setCellValue(student.getAdmissionDate()) : 
    studentRow.createCell(2).setBlank());
studentCount  ;