Create Excel file in Java

Question

I want to create an Excel file and write data just like writing a text file with Java. I tried to change file extension from .txt to .xls. But I wa

Answer 1

//Find jar from here "http://poi.apache.org/download.html"
import  java.io.*;
import  org.apache.poi.hssf.usermodel.HSSFSheet;
import  org.apache.poi.hssf.usermodel.HSSFWorkbook;
import  org.apache.poi.hssf.usermodel.HSSFRow;

public class CreateExlFile{
    public static void main(String[]args) {
        try {
            String filename = "C:/NewExcelFile.xls" ;
            HSSFWorkbook workbook = new HSSFWorkbook();
            HSSFSheet sheet = workbook.createSheet("FirstSheet");  

            HSSFRow rowhead = sheet.createRow((short)0);
            rowhead.createCell(0).setCellValue("No.");
            rowhead.createCell(1).setCellValue("Name");
            rowhead.createCell(2).setCellValue("Address");
            rowhead.createCell(3).setCellValue("Email");

            HSSFRow row = sheet.createRow((short)1);
            row.createCell(0).setCellValue("1");
            row.createCell(1).setCellValue("Sankumarsingh");
            row.createCell(2).setCellValue("India");
            row.createCell(3).setCellValue("sankumarsingh@gmail.com");

            FileOutputStream fileOut = new FileOutputStream(filename);
            workbook.write(fileOut);
            fileOut.close();
            workbook.close();
            System.out.println("Your excel file has been generated!");

        } catch ( Exception ex ) {
            System.out.println(ex);
        }
    }
}

Answer 2

Flat files do not allow providing meta information.

I would suggest writing out a HTML table containing the information you need, and let Excel read it instead. You can then use <b> tags to do what you ask for.

Answer 3

You can use Apache POI for creating native binary xls files.

Or you can use JExcelApi which is another, and somewhat light-weight as far as I can remember, Java library for Excel.

Answer 4

File fileName = new File(".....\\Fund.xlsx");

public static void createWorkbook(File fileName) throws IOException {
    try {
        FileOutputStream fos = new FileOutputStream(fileName);
        XSSFWorkbook  workbook = new XSSFWorkbook();            

        XSSFSheet sheet = workbook.createSheet("fund");  

        Row row = sheet.createRow(0);   
        Cell cell0 = row.createCell(0);
        cell0.setCellValue("Nav Value");

        Cell cell1 = row.createCell(1);

        cell1.setCellValue("Amount Change");       

        Cell cell2 = row.createCell(2);
        cell2.setCellValue("Percent Change");

        workbook.write(fos);
        fos.flush();
        fos.close();
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

Answer 5

I've created the API "generator-excel" to create an Excel file, below the dependecy:

<dependency>
  <groupId>com.github.bld-commons.excel</groupId>
  <artifactId>generator-excel</artifactId>
  <version>3.1.0</version>
</dependency>

This library can to configure the styles, the functions, the charts, the pivot table and etc. through a series of annotations.
You can write rows by getting data from a datasource trough a query with or without parameters.
Below an example to develop

1. I created 2 classes that represents the row of the table.

package bld.generator.report.junit.entity;
    
    import java.util.Date;
    
    import org.apache.poi.ss.usermodel.HorizontalAlignment;
    
    import bld.generator.report.excel.RowSheet;
    import bld.generator.report.excel.annotation.ExcelCellLayout;
    import bld.generator.report.excel.annotation.ExcelColumn;
    import bld.generator.report.excel.annotation.ExcelDate;
    import bld.generator.report.excel.annotation.ExcelImage;
    import bld.generator.report.excel.annotation.ExcelRowHeight;
    
    @ExcelRowHeight(height = 3)
    public class UtenteRow implements RowSheet {
        
        @ExcelColumn(columnName = "Id", indexColumn = 0)
        @ExcelCellLayout(horizontalAlignment = HorizontalAlignment.RIGHT)
        private Integer idUtente; 
        @ExcelColumn(columnName = "Nome", indexColumn = 2)
        @ExcelCellLayout
        private String nome; 
        @ExcelColumn(columnName = "Cognome", indexColumn = 1)
        @ExcelCellLayout
        private String cognome;
        @ExcelColumn(columnName = "Data di nascita", indexColumn = 3)
        @ExcelCellLayout(horizontalAlignment = HorizontalAlignment.CENTER)
        @ExcelDate
        private Date dataNascita;
        @ExcelColumn(columnName = "Immagine", indexColumn = 4)
        @ExcelCellLayout
        @ExcelImage(resizeHeight = 0.7, resizeWidth = 0.6)
        private byte[] image;   
        
        @ExcelColumn(columnName = "Path", indexColumn = 5)
        @ExcelCellLayout
        @ExcelImage(resizeHeight = 0.7, resizeWidth = 0.6)
        private String path;    
        
    
        public UtenteRow() {
        }
    
    
        public UtenteRow(Integer idUtente, String nome, String cognome, Date dataNascita) {
            super();
            this.idUtente = idUtente;
            this.nome = nome;
            this.cognome = cognome;
            this.dataNascita = dataNascita;
        }
    
    
        public Integer getIdUtente() {
            return idUtente;
        }
    
    
        public void setIdUtente(Integer idUtente) {
            this.idUtente = idUtente;
        }
    
    
        public String getNome() {
            return nome;
        }
    
    
        public void setNome(String nome) {
            this.nome = nome;
        }
    
    
        public String getCognome() {
            return cognome;
        }
    
    
        public void setCognome(String cognome) {
            this.cognome = cognome;
        }
    
    
        public Date getDataNascita() {
            return dataNascita;
        }
    
    
        public void setDataNascita(Date dataNascita) {
            this.dataNascita = dataNascita;
        }
    
    
        public byte[] getImage() {
            return image;
        }
    
    
        public String getPath() {
            return path;
        }
    
    
        public void setImage(byte[] image) {
            this.image = image;
        }
    
    
        public void setPath(String path) {
            this.path = path;
        }
    
    }




package bld.generator.report.junit.entity;

import org.apache.poi.ss.usermodel.DataConsolidateFunction;
import org.apache.poi.ss.usermodel.HorizontalAlignment;

import bld.generator.report.excel.RowSheet;
import bld.generator.report.excel.annotation.ExcelCellLayout;
import bld.generator.report.excel.annotation.ExcelColumn;
import bld.generator.report.excel.annotation.ExcelFont;
import bld.generator.report.excel.annotation.ExcelSubtotal;
import bld.generator.report.excel.annotation.ExcelSubtotals;

@ExcelSubtotals(labelTotalGroup = "Total",endLabel = "total")
public class SalaryRow implements RowSheet {

    @ExcelColumn(columnName = "Name", indexColumn = 0)
    @ExcelCellLayout
    private String name;
    @ExcelColumn(columnName = "Amount", indexColumn = 1)
    @ExcelCellLayout(horizontalAlignment = HorizontalAlignment.RIGHT)
    @ExcelSubtotal(dataConsolidateFunction = DataConsolidateFunction.SUM,excelCellLayout = @ExcelCellLayout(horizontalAlignment = HorizontalAlignment.RIGHT,font=@ExcelFont(bold = true)))
    private Double amount;
    
    public SalaryRow() {
        super();
    }
    public SalaryRow(String name, Double amount) {
        super();
        this.name = name;
        this.amount = amount;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Double getAmount() {
        return amount;
    }
    public void setAmount(Double amount) {
        this.amount = amount;
    }
    
}

2. I created 2 class that represents the sheets.

package bld.generator.report.junit.entity;

import javax.validation.constraints.Size;

import bld.generator.report.excel.QuerySheetData;
import bld.generator.report.excel.annotation.ExcelHeaderLayout;
import bld.generator.report.excel.annotation.ExcelMarginSheet;
import bld.generator.report.excel.annotation.ExcelQuery;
import bld.generator.report.excel.annotation.ExcelSheetLayout;

@ExcelSheetLayout
@ExcelHeaderLayout
@ExcelMarginSheet(bottom = 1.5, left = 1.5, right = 1.5, top = 1.5)
@ExcelQuery(select = "SELECT id_utente, nome, cognome, data_nascita,image,path "
        + "FROM utente "
        + "WHERE cognome=:cognome "
        + "order by cognome,nome")
public class UtenteSheet extends QuerySheetData<UtenteRow> {
    

    public UtenteSheet(@Size(max = 31) String sheetName) {
        super(sheetName);
    }

    
}




package bld.generator.report.junit.entity;

import javax.validation.constraints.Size;

import bld.generator.report.excel.SheetData;
import bld.generator.report.excel.annotation.ExcelHeaderLayout;
import bld.generator.report.excel.annotation.ExcelMarginSheet;
import bld.generator.report.excel.annotation.ExcelSheetLayout;
@ExcelSheetLayout
@ExcelHeaderLayout
@ExcelMarginSheet(bottom = 1.5,left = 1.5,right = 1.5,top = 1.5)
public class SalarySheet extends SheetData<SalaryRow> {

    public SalarySheet(@Size(max = 31) String sheetName) {
        super(sheetName);
    }

}

3. Class test, in the test function there are antoher sheets

package bld.generator.report.junit;

import java.util.ArrayList;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.List;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import bld.generator.report.excel.BaseSheet;
import bld.generator.report.excel.GenerateExcel;
import bld.generator.report.excel.data.ReportExcel;
import bld.generator.report.junit.entity.AutoreLibriSheet;
import bld.generator.report.junit.entity.CasaEditrice;
import bld.generator.report.junit.entity.GenereSheet;
import bld.generator.report.junit.entity.SalaryRow;
import bld.generator.report.junit.entity.SalarySheet;
import bld.generator.report.junit.entity.TotaleAutoreLibriRow;
import bld.generator.report.junit.entity.TotaleAutoreLibriSheet;
import bld.generator.report.junit.entity.UtenteSheet;
import bld.generator.report.utils.ExcelUtils;

/**
 * The Class ReportTest.
 */
@RunWith(SpringRunner.class)
@SpringBootTest
@ConfigurationProperties
@ComponentScan(basePackages = {"bld.generator","bld.read"})
@EnableTransactionManagement
public class ReportTestJpa {

    /** The Constant PATH_FILE. */
    private static final String PATH_FILE = "/mnt/report/";

    /** The generate excel. */
    @Autowired
    private GenerateExcel generateExcel;

    /**
     * Sets the up.
     *
     * @throws Exception the exception
     */
    @Before
    public void setUp() throws Exception {
    }

    /**
     * Test.
     *
     * @throws Exception the exception
     */
    @Test
    public void test() throws Exception {
        List<BaseSheet> listBaseSheet = new ArrayList<>();
        
        UtenteSheet utenteSheet=new UtenteSheet("Utente");
        utenteSheet.getMapParameters().put("cognome", "Rossi");
        listBaseSheet.add(utenteSheet);
        
        CasaEditrice casaEditrice = new CasaEditrice("Casa Editrice","Mondadori", new GregorianCalendar(1955, Calendar.MAY, 10), "Roma", "/home/francesco/Documents/git-project/dev-excel/linux.jpg","Drammatico");
        listBaseSheet.add(casaEditrice);
        
        
        AutoreLibriSheet autoreLibriSheet = new AutoreLibriSheet("Libri d'autore","Test label");
        TotaleAutoreLibriSheet totaleAutoreLibriSheet=new TotaleAutoreLibriSheet();
        totaleAutoreLibriSheet.getListRowSheet().add(new TotaleAutoreLibriRow("Totale"));
        autoreLibriSheet.setSheetFunctionsTotal(totaleAutoreLibriSheet);
        listBaseSheet.add(autoreLibriSheet);
        GenereSheet genereSheet=new GenereSheet("Genere");
        listBaseSheet.add(genereSheet);
        SalarySheet salarySheet=new SalarySheet("salary");
        salarySheet.getListRowSheet().add(new SalaryRow("a",2.0));
        salarySheet.getListRowSheet().add(new SalaryRow("a",2.0));
        salarySheet.getListRowSheet().add(new SalaryRow("a",2.0));
        salarySheet.getListRowSheet().add(new SalaryRow("a",2.0));
        salarySheet.getListRowSheet().add(new SalaryRow("c",1.0));
        salarySheet.getListRowSheet().add(new SalaryRow("c",1.0));
        salarySheet.getListRowSheet().add(new SalaryRow("c",1.0));
        salarySheet.getListRowSheet().add(new SalaryRow("c",1.0));
        listBaseSheet.add(salarySheet);
        ReportExcel excel = new ReportExcel("Mondadori JPA", listBaseSheet);

        byte[] byteReport = this.generateExcel.createFileXlsx(excel);

        ExcelUtils.writeToFile(PATH_FILE,excel.getTitle(), ".xlsx", byteReport);

    }

    

}

4. Application yaml

logging:
  level:
    root: WARN
    org:
      springframework:
        web: DEBUG
      hibernate: ERROR



spring:
  datasource:
    url: jdbc:postgresql://localhost:5432/excel_db
    username: ${EXCEL_USER_DB}
    password: ${EXCEL_PASSWORD_DB}
  jpa:
    show-sql: true
    properties:
      hibernate:
        default_schema: public
        jdbc:
          lob:
            non_contextual_creation: true 
        format_sql: true    
        ddl-auto: auto
    database-platform: org.hibernate.dialect.PostgreSQLDialect
    generate-ddl: true

below the link of the project on github:

• https://github.com/bld-commons/dev-excel

Answer 6

Fair warning about Apache POI's Excel generation... (I know this is an old post, but it's important in case someone looks this up again like I just did)

It had a memory leak issue, which supposedly was solved by 2006, but which people quite recently have still been experiencing. If you want to automate generating a large amount of excel (i.e., if you want to generate a single, large file, a large number of small files, or both), I'd recommend using a different API. Either that, or increasing the JVM stack size to preposterous proportions, and maybe looking into interning strings if you know you won't actually be working with many different strings (although, of course, interning strings means that if you have a large number of different strings, you'll have an entirely different program-crashing memory problem. So, consider that before you go that route).