1. Overview
A Microsoft Excel cell can have different types like string, numeric, boolean, and formula.
In this quick tutorial, we’ll show how to read the cell value as a string – regardless of the cell type – with Apache POI.
2. Apache POI
To begin with, we first need to add the poi dependency to our project pom.xml file:
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>5.2.5</version>
</dependency>
Apache POI uses the Workbook interface to represent an Excel file. It also uses Sheet, Row, and Cell interfaces to model different levels of elements in an Excel file. At the Cell level, we can use its getCellType() method to get the cell type. Apache POI supports the following cell types:
- BLANK
- BOOLEAN
- ERROR
- FORMULA
- NUMERIC
- STRING
If we want to display the Excel file content on the screen, we would like to get the string representation of a cell, instead of its raw value. Therefore, for cells that are not of type STRING, we need to convert their data into string values.
We can use DataFormatter to fetch the string value of an Excel cell. It can get a formatted string representation of the value stored in a cell. For example, if a cell’s numeric value is 1.234, and the format rule of this cell is two decimal points, we’ll get string representation “1.23”:
Cell cell = // a numeric cell with value of 1.234 and format rule "0.00"
DataFormatter formatter = new DataFormatter();
String strValue = formatter.formatCellValue(cell);
assertEquals("1.23", strValue);
Therefore, the result of DataFormatter.formatCellValue() is the display string exactly as it appears in Excel.
If the cell’s type is FORMULA, the previous method will return the original formula string, instead of the calculated formula value. Therefore, to get the string representation of the formula value, we need to use FormulaEvaluator to evaluate the formula:
Workbook workbook = // existing Workbook setup
FormulaEvaluator evaluator = workbook.getCreationHelper().createFormulaEvaluator();
Cell cell = // a formula cell with value of "SUM(1,2)"
DataFormatter formatter = new DataFormatter();
String strValue = formatter.formatCellValue(cell, evaluator);
assertEquals("3", strValue);
This method is general to all cell types. If the cell type is FORMULA, we’ll evaluate it using the given FormulaEvaluator. Otherwise, we’ll return the string representation without any evaluations.
5. Summary
In this quick article, we showed how to get the string representation of an Excel cell, regardless of its type. As always, the source code for the article is available over on GitHub.
