how to read a excel file in java

To read an Excel file in Java, you can use the Apache POI library. Apache POI is a Java library that allows you to read and write Microsoft Office documents, such as Excel, PowerPoint, and Word files.

Here is an example of how you can use Apache POI to read an Excel file in Java:

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

public class ExcelReader {
    public static void main(String[] args) throws IOException {
        FileInputStream inputStream = new FileInputStream(new File("example.xlsx"));
        Workbook workbook = new XSSFWorkbook(inputStream);
        Sheet sheet = workbook.getSheetAt(0);

        for (Row row : sheet) {
            for (Cell cell : row) {
                System.out.print(cell.getStringCellValue() + " ");
            }
            System.out.println();
        }

        workbook.close();
        inputStream.close();
    }
}

In this example, the main method opens an input stream to the Excel file using the FileInputStream class. It then creates a Workbook object using the XSSFWorkbook class, which is part of the Apache POI library and is used to read .xlsx files (the latest version of Excel).

The Workbook object is used to get the first sheet of the Excel file using the getSheetAt method. The sheet is then iterated over using a loop, and each row is iterated over using another loop.

The cell values are extracted using the getStringCellValue method of the Cell class and printed to the console using the System.out.print method.

This code will read the data from the Excel file and print it to the console. You can modify the code to store the data in a data structure or perform other operations with it.

Keep in mind that this is just one way to read an Excel file in Java. You can use different techniques and libraries to achieve the same result, such as using the HSSFWorkbook class to read .xls files (the older version of Excel) or using a different library to parse the Excel file.