How do I Export Data to Excel using Spring, Hibernate, and PostgreSQL?

Question

I have a project which has one model class, Person with three Columns: id, name, and country, which correctly persists to PostgreSQL. The results are correctly found in List objects. But I want to export the List data (which displays on the page) to Excel.

I made a class named PersonExcelView :

public class PersonExcelView extends AbstractExcelView {
    private PersonService personService;
    @Override
    protected void buildExcelDocument(Map<String, Object> arg0, HSSFWorkbook arg1, HttpServletRequest arg2,
            HttpServletResponse arg3) throws Exception {
            HSSFWorkbook workbook = new HSSFWorkbook();
            HSSFSheet excelSheet = workbook.createSheet("PersonList");
            setExcelHeader(excelSheet);

        List personList = (List) personService.getPersonList();
        setExcelRows(excelSheet,personList);

    }

    public void setExcelHeader(HSSFSheet excelSheet) {
        HSSFRow excelHeader = excelSheet.createRow(0);
        excelHeader.createCell(0).setCellValue("Id");
        excelHeader.createCell(1).setCellValue("Name");
        excelHeader.createCell(2).setCellValue("Country");
    }

    public void setExcelRows(HSSFSheet excelSheet, List personList){
        int record = 1;
        for (Person person : personService.listPersons()) {
            HSSFRow excelRow = excelSheet.createRow(record++);
            excelRow.createCell(0).setCellValue(person.getId());
            excelRow.createCell(1).setCellValue(person.getName());
            excelRow.createCell(2).setCellValue(person.getCountry());

    }

}}

Here is my PersonServiceImpl class:

@Service
public class PersonServiceImpl implements PersonService {

    private PersonDAO personDAO;

    public void setPersonDAO(PersonDAO personDAO) {
        this.personDAO = personDAO;
    }

    @Override
    @Transactional
    public void addPerson(Person p) {
        this.personDAO.addPerson(p);
    }

    @Override
    @Transactional
    public void updatePerson(Person p) {
        this.personDAO.updatePerson(p);
    }

    @Override
    @Transactional
    public List<Person> listPersons() {
        return this.personDAO.listPersons();
    }

    @Override
    @Transactional
    public Person getPersonById(int id) {
        return this.personDAO.getPersonById(id);
    }

    @Override
    @Transactional
    public void removePerson(int id) {
        this.personDAO.removePerson(id);
    }

    @Override
    public List<Person> getPersonList() {
        // TODO Auto-generated method stub
        return listPersons();
    }

}

Here is my Controller code:

 @RequestMapping(value = "/export", method = RequestMethod.POST)
    public ModelAndView getExcel() {
        List personList = (List) personService.getPersonList();
        return new ModelAndView("PersonExcelView", "personList", personList);
    }

and here is the JSP:

<a href="SpringMVCHibernate/export">Export</a></h3>

When I click export, it does not export the data into Excel. Where is the error?

Answer 1

Use below code for exporting data to excel sheet and do changes as per your code requirement.

 XSSFWorkbook workbook = new XSSFWorkbook();           
              XSSFSheet spreadsheet = workbook.createSheet("PersonList");         
              XSSFRow row;      
                     for (Object obj : objectArr)// for (Person person : personService.listPersons()) 
                     {
                        Cell cell = row.createCell(cellid++);
                        cell.setCellValue((String)obj);
                     }               
                for(int columnIndex = 0; columnIndex < 24; columnIndex++) {
                      spreadsheet.autoSizeColumn(columnIndex);
                    }

                      if(List.size()!=0)
                      {
                          FileOutputStream out;                      
                          out = new FileOutputStream(new File(file_path));                     
                          workbook.write(out);
                          out.close();
                      }