[Library] 자바(Java)로 엑셀파일 만들기 [Apache POI, 마이크로소프트 오피스 지원 라이브러리]

[Library] 자바(Java)로 엑셀파일 읽기(.xls, .xlsx) [Apache POI, 마이크로소프트 오피스 지원 라이브러리]

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- 자바(Java)로 엑셀파일 만들기

- WriteExcel.java

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

import java.io.File;
import java.io.FileOutputStream;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

public class WriteExcel {
    public static void main(String[] args) {
        //Blank workbook
        XSSFWorkbook workbook = new XSSFWorkbook();

        //Create a blank sheet
        XSSFSheet sheet = workbook.createSheet("Employee Data");

        //This data needs to be written (Object[])
        Map<String, Object[]> data = new TreeMap<>();
        data.put("1", new Object[] {"ID", "NAME", "LASTNAME"});
        data.put("2", new Object[] {1, "Amit", "Shukla"});
        data.put("3", new Object[] {2, "Lokesh", "Gupta"});
        data.put("4", new Object[] {3, "John", "Adwards"});
        data.put("5", new Object[] {4, "Brian", "Schultz"});

        //Iterate over data and write to sheet
        Set<String> keyset = data.keySet();
        int rownum = 0;
        
        for (String key : keyset) {
            Row row = sheet.createRow(rownum++);
            Object [] objArr = data.get(key);
            int cellnum = 0;
            
            for (Object obj : objArr) {
                Cell cell = row.createCell(cellnum++);
                if(obj instanceof String) {
                    cell.setCellValue((String)obj);
                }
                else if(obj instanceof Integer) {
                    cell.setCellValue((Integer)obj);
                }
            }
        }
        try {
            //Write the workbook in file system
            FileOutputStream out = new FileOutputStream(new File("src/data/howtodoinjava_demo.xlsx"));
            workbook.write(out);
            out.close();
            
            System.out.println("howtodoinjava_demo.xlsx written successfully on disk.");
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
}

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Excel 파일 생성 완료

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- 참고자료

Apache POI - Read and Write Excel File in Java

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