java 合并excel

Java可以使用Apache POI库来操作Excel文件，包括合并多个Excel文件。

以下是一个示例代码，使用POI库来合并两个Excel文件：

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;

public class ExcelMerger {

    public static void main(String[] args) throws Exception {
        // 读取第一个Excel文件
        FileInputStream fileInputStream1 = new FileInputStream(new File("file1.xls"));
        HSSFWorkbook workbook1 = new HSSFWorkbook(fileInputStream1);
        HSSFSheet sheet1 = workbook1.getSheetAt(0);

        // 读取第二个Excel文件
        FileInputStream fileInputStream2 = new FileInputStream(new File("file2.xls"));
        HSSFWorkbook workbook2 = new HSSFWorkbook(fileInputStream2);
        HSSFSheet sheet2 = workbook2.getSheetAt(0);

        // 合并两个Excel文件
        List<Row> rows = new ArrayList<Row>();
        Iterator<Row> rowIterator = sheet1.iterator();
        while (rowIterator.hasNext()) {
            rows.add(rowIterator.next());
        }
        rowIterator = sheet2.iterator();
        while (rowIterator.hasNext()) {
            rows.add(rowIterator.next());
        }

        // 创建新的Excel文件
        HSSFWorkbook workbook = new HSSFWorkbook();
        HSSFSheet sheet = workbook.createSheet("merged");

        // 将合并的行写入新的Excel文件
        int rowIndex = 0;
        for (Row row : rows) {
            HSSFRow newRow = sheet.createRow(rowIndex++);
            int cellIndex = 0;
            Iterator<Cell> cellIterator = row.cellIterator();
            while (cellIterator.hasNext()) {
                Cell cell = cellIterator.next();
                newRow.createCell(cellIndex++).setCellValue(cell.getStringCellValue());
            }
        }

        // 保存新的Excel文件
        FileOutputStream fileOutputStream = new FileOutputStream(new File("merged.xls"));
        workbook.write(fileOutputStream);
        fileOutputStream.close();
    }

}

这个示例代码将`file1.xls`和`file2.xls`两个Excel文件合并为一个新的Excel文件`merged.xls`，新的Excel文件只包含第一个sheet的数据。