How list has map values write to excel file using Apache poi

Question

I\'m getting list hash map key and values like:{1=[ACSS Description1, ACSS Description2, ACSS Description3, SACSS Description4], 2=[11, 1, 4, 12]}

I wou

Answer 1

HashMap Sheetmap = new HashMap();

     SheetColumnName s1 = new  SheetColumnName(1);
     s1.setFile_Name("Censtar Energy- Elect.xlsx");

     Sheetmap.put(s1, s1.setState("A7"));
     Sheetmap.put(s1, s1.setZone("B7"));

     SheetColumnName s2 = new  SheetColumnName(2);
     s2.setFile_Name("Direct Energy- Elect.xls"); 
     Sheetmap.put(s2, s2.setState("A55"));

     System.out.println(Sheetmap.get(s1));
     System.out.println(Sheetmap.get(s2));

    Collection<String> values = Sheetmap.values();

     ArrayList<String> listOfValues = new ArrayList<String>(values);

     for (String value : listOfValues) 
     {
            System.out.println(value);
            FileReader fileReader=new FileReader();
            fileReader.ProcessFile(s1.getFile_Name(),value);
     }

Answer 2

I create a class contains methods that will help you to:

Put your data from Criteria criteria=hibernateTemplate.getSessionFactory().openSession().createCriteria(ExportReport.‌​class); List<ExportReport> list = criteria.list(); to a map

Create a Xlsx file and initialize it with the number of the rows and cells needed for writing the data from map.

Write the data from map to Xlsx file

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;


public class UtilsMethod {

    private XSSFWorkbook workbook = new XSSFWorkbook();

    /*
     * Take a Map of integer and List of string and
     *Create a Xlsx file on given path with number of row equal to size of nameList And number of Cell equal to keyset size
     */
    public void initializeExcelFile(Map<Integer,List<String>>hashmap,String path) throws IOException{

        FileOutputStream out = new FileOutputStream( new File(path));
        Set<Integer> keyset = hashmap.keySet();
        XSSFSheet sheet = workbook.createSheet();
        XSSFRow row = null;
        List<String> nameList = hashmap.get(keyset.toArray()[0]);

        for(int j=1; j<nameList.size()+1;j++){
            row = sheet.createRow(j);
            if(null != row){
                for(int i=0;i<keyset.size();i++){
                    row.createCell(i);
                }
            }
        }

        workbook.write(out);
        out.close();
    }

    /*
     * Use initializeExcelFile(hashmap,path) to initialize a Xlsx file in given path 
     * After that, write the  content of hashmap into Xlsx file
     */
    public void writeToExcelfile(Map<Integer,List<String>>hashmap,String path) throws IOException{

        Set<Integer> keyset = hashmap.keySet();
        InputStream inp = new FileInputStream( new File(path));
        FileOutputStream out = new FileOutputStream( new File(path));
        int rownum = 1;
        int cellnum = 0;

        initializeExcelFile(hashmap,path);

        workbook = new XSSFWorkbook(inp);

        XSSFSheet sheet = workbook.getSheetAt(0);

        for(Integer key : keyset){
            List<String> nameList = hashmap.get(key);
            for(String s : nameList){
                XSSFRow row = sheet.getRow(rownum++);
                Cell cell = row.getCell(cellnum);
                if(null!=cell){
                    cell.setCellValue(s);
                }
            }
            cellnum++;
            rownum=1;
        }

        workbook.write(out);
        out.close();
        inp.close();
    }

    public Map<Integer,List<String>> putListIntoMap(List<ExportReport>exportReports) {

        Map<Integer,List<String>> exportRep = new TreeMap<Integer, List<String>>();
        List<String> descriptions = new ArrayList<String>();
        List<String> exportIntervalIds = new ArrayList<String>();

        for(ExportReport report:exportReports){
            descriptions.add(report.getDescription());
            exportIntervalIds.add(report.getExportIntervalId().toString());
        }

        exportRep.put(1, descriptions);
        exportRep.put(2, exportIntervalIds);

        return exportRep;
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

}

And test Class for testing all UtilsMethod class' method

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;


public class Test {


    public static void main(String[] args) throws IOException {

        ExportReport exportReport = new ExportReport();
        exportReport.setExportIntervalId(11);
        exportReport.setDescription("ACCSDESCRIPTION1");

        ExportReport exportReport2 = new ExportReport();
        exportReport2.setExportIntervalId(1);
        exportReport2.setDescription("ACCSDESCRIPTION2");

        ExportReport exportReport3 = new ExportReport();
        exportReport3.setExportIntervalId(4);
        exportReport3.setDescription("ACCSDESCRIPTION3");

        ExportReport exportReport4 = new ExportReport();
        exportReport4.setExportIntervalId(12);
        exportReport4.setDescription("ACCSDESCRIPTION4");

        List<ExportReport> exportReports = new ArrayList<ExportReport>();

        exportReports.add(exportReport);
        exportReports.add(exportReport2);
        exportReports.add(exportReport3);
        exportReports.add(exportReport4);

        UtilsMethod utilsMethod = new UtilsMethod();

        Map<Integer,List<String>> map = utilsMethod.putListIntoMap(exportReports);
        System.out.println(map);


        utilsMethod.writeToExcelfile(map, "Writesheet.xlsx");

        System.out.println("Writesheet.xlsx written successfully" );

    }

}

After running Test class, you will get this Xlsx file