Java POI库从入门到精通举例详解

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.2</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>4.1.2</version>
</dependency>

import org.apache.poi.ss.usermodel.*;

public class CreateExcelFile {
    public static void main(String[] args) {
        // 创建一个新的工作簿
        Workbook workbook = new XSSFWorkbook();

        // 创建一个工作表
        Sheet sheet = workbook.createSheet("新建表格");

        // 创建一个行，并在其中创建一个单元格
        Row row = sheet.createRow(0);
        Cell cell = row.createCell(0);
        cell.setCellValue("Hello, POI!");

        // 写出到文件
        try (FileOutputStream fileOut = new FileOutputStream("workbook.xlsx")) {
            workbook.write(fileOut);
        } catch (IOException e) {
            e.printStackTrace();
        }

        // 关闭工作簿
        try {
            workbook.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import org.apache.poi.ss.usermodel.*;

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

public class ReadModifyExcel {
    public static void main(String[] args) {
        try {
            // 加载Excel文件
            FileInputStream file = new FileInputStream(new File("workbook.xlsx"));
            Workbook workbook = new XSSFWorkbook(file);

            // 获取第一个工作表
            Sheet sheet = workbook.getSheetAt(0);

            // 获取第一行，并更新其中的单元格内容
            Row row = sheet.getRow(0);
            Cell cell = row.getCell(0);
            cell.setCellValue("Hello, POI! Updated");

            // 写回到文件
            FileOutputStream fileOut = new FileOutputStream("workbook.xlsx");
            workbook.write(fileOut);
            fileOut.close();

            // 关闭工作簿
            workbook.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import org.apache.poi.ss.usermodel.*;

public class ExcelCellStyle {
    public static void main(String[] args) {
        Workbook workbook = new XSSFWorkbook();
        Sheet sheet = workbook.createSheet("样式设置");

        // 创建字体
        Font font = workbook.createFont();
        font.setFontHeightInPoints((short) 14);
        font.setFontName("Arial");
        font.setBold(true);
        font.setColor(IndexedColors.BLUE.getIndex());

        // 创建单元格样式
        CellStyle style = workbook.createCellStyle();
        style.setFont(font);

        // 创建行和单元格，并应用样式
        Row row = sheet.createRow(0);
        Cell cell = row.createCell(0);
        cell.setCellValue("样式设置示例");
        cell.setCellStyle(style);

        // 写出到文件
        try (FileOutputStream fileOut = new FileOutputStream("workbook.xlsx")) {
            workbook.write(fileOut);
        } catch (IOException e) {
            e.printStackTrace();
        }

        // 关闭工作簿
        try {
            workbook.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import org.apache.poi.ss.usermodel.*;

public class ExcelFormula {
    public static void main(String[] args) {
        Workbook workbook = new XSSFWorkbook();
        Sheet sheet = workbook.createSheet("公式计算");

        // 创建行和单元格
        Row row = sheet.createRow(0);

        // 设置数值
        Cell cell1 = row.createCell(0);
        cell1.setCellValue(10);

        Cell cell2 = row.createCell(1);
        cell2.setCellValue(20);

        // 创建公式
        Cell formulaCell = row.createCell(2);
        formulaCell.setCellFormula("A1 + B1");

        // 写出到文件
        try (FileOutputStream fileOut = new FileOutputStream("workbook.xlsx")) {
            workbook.write(fileOut);
        } catch (IOException e) {
            e.printStackTrace();
        }

        // 关闭工作簿
        try {
            workbook.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}