From excel to xml java

Office OpenXML, also known as OpenXML or OOXML, is a zipped, XML-based format developed by Microsoft. It can include Word documents, Excel spreadsheets, PowerPoint presentations, and Charts, Diagrams, Shapes, etc. This article will share how to Convert Excel to Office Open XML and then convet it back using a free Java library named Free Spire.XLS for Java.

Install the free library (2 Method)

1# Download the free library and unzip it, then add the Spire.Xls.jar file to your project as dependency.
2# Directly add the jar dependency to maven project by adding the following configurations to the pom.xml.

<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <name>e-iceblue</name>
        <url>http://repo.e iceblue.com/nexus/content/groups/public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>e-iceblue</groupId>
        <artifactId>spire.xls.free</artifactId>
        <version>5.1.0</version>
    </dependency>
</dependencies>

Convert Excel to Office Open XML Using Java

Free Spire.XLS for Java offers the Workbook.saveAsXml() method to save the Excel file as Office Open XML.

import com.spire.xls.Workbook;

public class ExcelToOpenXML {
    public static void main(String []args){
        //Create a Workbook instance
        Workbook workbook = new Workbook();
        //Load an Excel file
        workbook.loadFromFile("Sales1.xlsx");

        //Save as Office Open XML file format
        workbook.saveAsXml("ToXML.xml");
    }
}

Convert Office Open XML to Excel in Java

Using the Workbook.saveToFile() method, you can save the Office Open XML file as Excel.

import com.spire.xls.ExcelVersion;
import com.spire.xls.Workbook;

public class OpenXmlToExcel {
    public static void main(String []args){
        //Create an instance of Workbook class
        Workbook workbook = new Workbook();
        //Load an Office Open XML file
        workbook.loadFromXml("ToXML.xml");

        //Save as Excel XLSX file format
        workbook.saveToFile("ToExcel.xlsx", ExcelVersion.Version2016);
    }
}

Работа с Excel в Java через Apache POI

Из этой статьи вы сможете узнать о записи и чтении данных из Excel файлов в Java (будет рассмотрен как XLS , так и XLSX формат). Мы будем использовать библиотеку Apache POI и сосредоточимся на работе с типами String и Date , работа с последним происходит достаточно хитро. Напомню, что работу с числами мы уже рассмотрели в другой статье.

Библиотеку poi-XX.jar вы можете использовать для всех старых ( xls , doc , ppt ) файлов Microsoft Office, для новых ( xlsx , docx , pptx ) вам понадобится poi-ooxml-XX.jar . Очень важно понимать, что к чему относится, т.к. используемые классы тоже разные — для старых расширений это HSSFWorkbook , а для новых — XSSFWorkbook .

Подготовка: загрузка библиотек и зависимостей

Конечно, существует достаточно много открытых библиотек, которые позволяют работать с Excel файлами в Java, например, JXL, но мы будем использовать имеющую самый обширный API и самую популярную — Apache POI. Чтобы её использовать, вам нужно скачать jar файлы и добавить их через Eclipse вручную, или вы можете предоставить это Maven.

Во втором случае вам нужно просто добавить следующие две зависимости:

Самое удобное в Maven — что он загрузит не только указанные poi.jar и poi-ooxml.jar , но и все jar файлы, которые используются внутри, то есть xmlbeans-2.6.0.jar , stax-api-1.0.1.jar , poi-ooxml-schemas-3.12.jar и commons-codec-1.9.jar .

Если вы будете добавлять библиотеки вручную — не забудьте о вышеназванных файлах. Скачать всё можно отсюда. Помните — если вы загрузите только poi-XX.jar , то ваш код скомпилируется без ошибок, но потом упадёт с java.lang.NoClassDefFoundError: org/apache/xmlbeans/XmlObject , так как внутри будет вызываться xmlbeans.jar .

Запись

В этом примере мы запишем в xls файл следующие данные: в первую ячейку — строку с именем, а во вторую — дату рождения. Вот пошаговая инструкция:

• Создаём объект HSSFWorkBook ;
• Создаём лист, используя на объекте, созданном в предыдущем шаге, createSheet() ;
• Создаём на листе строку, используя createRow() ;
• Создаём в строке ячейку — createCell() ;
• Задаём значение ячейки через setCellValue();
• Записываем workbook в File через FileOutputStream ;
• Закрываем workbook , вызывая close() .

Для записи строк или чисел этого вполне достаточно, но чтобы записать дату, нам понадобится сделать ещё кое-что:

• Создать DateFormat ;
• Создать CellStyle ;
• Записать DateFormat в CellStyle ;
• Записать CellStyle в ячейку;
• Теперь в эту ячейку можно записать объект Date через всё тот же setCellValue ;
• Чтобы дата поместилась в ячейку, нам нужно добавить столбцу свойство автоматически менять размер: sheet.autoSizeColumn(1) .

Всё вместе это будет выглядеть так:

Чтение

Теперь мы считаем из только что созданного файла то, что мы туда записали.

• Для начала создадим HSSFWorkBook , передав в конструктор FileInputStream ;
• Получаем лист, передавая в getSheet() его номер или название;
• Получаем строку, используя getRow() ;
• Получаем ячейку, используя getCell() ;
• Узнаём тип ячейки, используя на ней getCellType() ;
• В зависимости от типа ячейки, читаем её значения, используя getStringCellValue() , getNumericCellValue() или getDateCellValue() ;
• Закрываем workbook используя close() .

Напомню, что дату Excel хранит как числа, т.е. тип ячейки всё равно будет CELL_TYPE_NUMERIC .

В виде кода это будет выглядеть следующим образом:

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Apache POI – Read and Write Excel File in Java

Last Updated: October 1, 2022

Learn to read excel, write excel, evaluate formula cells and apply custom formatting to the generated excel files using Apache POI library with examples.

If we are building software for the HR or Finance domain, there is usually a requirement for generating excel reports across management levels. Apart from reports, we can also expect some input data for the applications coming in the form of excel sheets and the application is expected to support this requirement.

Apache POI is a well-trusted library among many other open-source libraries to handle such usecases involving excel files. Please note that, in addition, we can read and write MS Word and MS PowerPoint files also using the Apache POI library.

This Apache POI tutorial will discuss some everyday excel operations in real-life applications.

1. Maven Dependency

If we are working on a maven project, we can include the Apache POI dependencies in pom.xml file using this:

2. Important Classes in POI Library

HSSF, XSSF and XSSF classes

Apache POI main classes usually start with either HSSF, XSSF or SXSSF.

• HSSF – is the POI Project’s pure Java implementation of the Excel 97(-2007) file format. e.g., HSSFWorkbook, HSSFSheet.
• XSSF – is the POI Project’s pure Java implementation of the Excel 2007 OOXML (.xlsx) file format. e.g., XSSFWorkbook, XSSFSheet.
• SXSSF (since 3.8-beta3) – is an API-compatible streaming extension of XSSF to be used when huge spreadsheets have to be produced and heap space is limited. e.g., SXSSFWorkbook, SXSSFSheet. SXSSF achieves its low memory footprint by limiting access to the rows within a sliding window, while XSSF gives access to all rows in the document.

Row and Cell

Apart from the above classes, Row and Cell interact with a particular row and a particular cell in an excel sheet.

FormulaEvaluator

Another helpful class FormulaEvaluator is used to evaluate the formula cells in an excel sheet.

3. Writing an Excel File

I am taking this example first so we can reuse the excel sheet created by this code in further examples.

Writing excel using POI is very simple and involves the following steps:

1. Create a workbook
2. Create a sheet in workbook
3. Create a row in sheet
4. Add cells to sheet
5. Repeat steps 3 and 4 to write more data

It seems very simple, right? Let’s have a look at the code doing these steps.

Java program to write an excel file using Apache POI library.

4. Reading an Excel File

Reading an excel file using POI is also very simple if we divide this into steps.

1. Create workbook instance from an excel sheet
2. Get to the desired sheet
3. Increment row number
4. iterate over all cells in a row
5. repeat steps 3 and 4 until all data is read

Let’s see all the above steps in code. I am writing the code to read the excel file created in the above example. It will read all the column names and the values in it – cell by cell.

Java program to read an excel file using Apache POI library.

5. Add and Evaluate Formula Cells

When working on complex excel sheets, we encounter many cells with formulas to calculate their values. These are formula cells. Apache POI also has excellent support for adding formula cells and evaluating already present formula cells.

Let’s see one example of how to add formula cells in excel?

The sheet has four cells in a row and the fourth one in the multiplication of all the previous 3 rows. So the formula will be: A2*B2*C2 (in the second row)

Java program to add formula in an excel file using Apache POI library.

Similarly, we want to read a file with formula cells and use the following logic to evaluate formula cells.

Java program to evaluate formula in an excel file using Apache POI library.

6. Formatting the Cells

So far we have seen examples of reading/writing and excel files using Apache POI. But, when creating a report in an excel file, it is essential to add formatting on cells that fit into any pre-determined criteria.

This formatting can be a different coloring based on a specific value range, expiry date limit etc.

In the below examples, we are taking a couple of such cell formatting examples for various purposes.

6.1. Cell value in a specific range

This code will color any cell in a range whose value is between a configured range. [e.g., between 50 and 70]

6.2. Highlight Duplicate Values

Highlight all cells which have duplicate values in observed cells.

6.3. Alternate Color Rows in Different Colors

A simple code to color each alternate row in a different color.

6.4. Color amounts that are going to expire in the next 30 days

A handy code for financial projects which keeps track of deadlines.

I am ending this apache poi tutorial here to keep the post within a limit.

7. Conclusion

In this tutorial, we learned to read excel, write excel, set and evaluate formula cells, and format the cells with color codings using the Apache POI library.

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Web technologies

Excel is a human readable and writable format, and XML is an important machine language. We need an efficient bridge between those two technologies.

Since 2007, the Excel files are a zip file containing XML data. Those XML files must be serialized into a minimal XML containing the cells data inside tags with the column headers as names. The resulting XML will look like that :

Here is the code to do it.

Read Excel file

In that post, I only treat the case of the recent XLSX format. I will use Apache POI and I want it to be able to manage very big files, so I have to use an event API.

The POI streaming API only treats the old XLS format. For XLSX, you have to use the SAX API which only helps you providing access to a stream of the XML of the sheets. The reading of the tags must be coded into your SAX handler and the given example is very useful but not complete.

The code in order to open a file and trigger the SAX reading is :

Write XML

As I said, I want that serializer to be fast. So I will not use a XML API in order to write the XML output. With some lines of codes, I write the content as a XML containing a namespace for reusability.

Here is the code :

Normalizing sheet names and column headers

In order to avoid issues with XML tag names, I normalize the sheet names and the column headers I found. It removes accents, normalizes spaces, and omits any characters which is not a letter, ‘_’ or a digit.

Here is the normalizing code :

Quick overview of XSLX format

The contents of the cells are inside the tag of the XML files of the sheets.
In the files I use, I saw 3 different structures :

• one with attribute t=»inlineStr» :

• a structure with the value in clear, with attribute t=»n» :

• and a last case, where it uses the “shared strings”. In that case the value is the index of the String in that list of shared strings :

I did not see any tag , as it is expected in example from Apache POI. And in the case of an attribute t=»inlineStr» , the value is in a tag instead of , as expected in example.

Whole code

You can download the whole code here :
FastXlsx2XmlSerializer

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How to convert Excel to XML using java?

i want to convert my input Excel file into the Output XML file.

If anybody has any solution in java for how to take input Excel file and how to write to XML as output,please give any code or any URL or any other solution.

5 Answers 5

Look into the jexcel or Apache POI libraries for reading in the Excel file.

Creating an XML file is simple, either just write the XML out to a file directly, or append to an XML Document and then write that out using the standard Java libs or Xerces or similar.

I have done conversion of Excel(xlsx) to xml in Java recently. I assumed each row in excel as a single object here. Here are the steps I followed:-

1. Read Excel file using Apache POI
2. Created a xsd file and generated corresponding classes
3. Read each row created, created corresponding objects and initilaized values using the generated getter/setter methods in the classes
4. Added the objects to an arraylist which holds only objects the same type
5. Using Jaxb Marshelled the arraylist object to an output file

JExcel was easy for me to use. Put jxl.jar on the classpath and code something like:

Download jxl and use this code

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How to read/write XML maps from/in excel with Apache POI in Java?

A little bit of context, in excel there is a tab named Developer, where you can see/add XML maps in the current workbook:

I am working with Apache POI and I want to read and also write XML maps in excel.

Do you know where can I found documentation regarding on how to read/write XML maps in excel using Apache POI?

1 Answer 1

To read XML mappings from existing workbooks there are API methods available.

There is XSSFWorkbook.getMapInfo which gets the MapInfo. And there is XSSFWorkbook.getCustomXMLMappings which gets a List of all the XSSFMap. So reading should not be the problem.

But until now there is nothing to create new MapInfo and/or putting additional schemas and/or maps in that MapInfo . So to create a new workbook having XML mappings using the low level underlaying objects is necessary.

The following complete example shows this. It provides methods to create a MapInfo and add schemas and maps to it. It uses the following class.xsd file as schema definition:

It creates a MapInfo , adds the schema and the map and creates a XSSFMap . Then it creates a XSSFTable in first scheet which refers to the map. So it is possible collecting data in that table to export as XML then.

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