java如何把两个excel拼接到一起

在Java中，将两个Excel文件拼接到一起，可以使用Apache POI库、将两个Excel文件合并到一个工作簿中、处理相同的列和行格式。下面将详细描述如何使用Apache POI库来实现这个目标。

Apache POI是一个强大的库，可以用来读写Excel文件。通过Apache POI，我们可以很方便地将两个Excel文件合并为一个。以下是详细步骤和代码示例。

一、导入Apache POI库

首先，你需要在项目中引入Apache POI库。你可以在Maven项目的pom.xml文件中添加以下依赖项：

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>5.2.0</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>5.2.0</version>
</dependency>
<dependency>
    <groupId>org.apache.xmlbeans</groupId>
    <artifactId>xmlbeans</artifactId>
    <version>5.1.1</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml-schemas</artifactId>
    <version>4.1.2</version>
</dependency>

二、读取Excel文件

在合并两个Excel文件之前，首先需要读取它们。以下是读取Excel文件的代码示例：

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import java.io.FileInputStream;
import java.io.IOException;
public class ExcelReader {
    public static Workbook readExcel(String filePath) throws IOException {
        FileInputStream fis = new FileInputStream(filePath);
        return new XSSFWorkbook(fis);
    }
}

三、合并Excel文件

接下来，我们需要将读取的两个Excel文件合并到一个工作簿中。以下是详细的代码示例：

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import java.io.FileOutputStream;
import java.io.IOException;
public class ExcelMerger {
    public static void mergeExcelFiles(String file1, String file2, String outputFile) throws IOException {
        Workbook workbook1 = ExcelReader.readExcel(file1);
        Workbook workbook2 = ExcelReader.readExcel(file2);
        Workbook mergedWorkbook = new XSSFWorkbook();
        Sheet mergedSheet = mergedWorkbook.createSheet("MergedSheet");
        int rowCount = 0;
        // Copy sheet1 to mergedSheet
        for (int i = 0; i < workbook1.getNumberOfSheets(); i++) {
            Sheet sheet = workbook1.getSheetAt(i);
            rowCount = copySheet(sheet, mergedSheet, rowCount);
        }
        // Copy sheet2 to mergedSheet
        for (int i = 0; i < workbook2.getNumberOfSheets(); i++) {
            Sheet sheet = workbook2.getSheetAt(i);
            rowCount = copySheet(sheet, mergedSheet, rowCount);
        }
        try (FileOutputStream fos = new FileOutputStream(outputFile)) {
            mergedWorkbook.write(fos);
        }
        workbook1.close();
        workbook2.close();
        mergedWorkbook.close();
    }
    private static int copySheet(Sheet sourceSheet, Sheet targetSheet, int startRow) {
        for (Row sourceRow : sourceSheet) {
            Row targetRow = targetSheet.createRow(startRow++);
            copyRow(sourceRow, targetRow);
        }
        return startRow;
    }
    private static void copyRow(Row sourceRow, Row targetRow) {
        for (Cell sourceCell : sourceRow) {
            Cell targetCell = targetRow.createCell(sourceCell.getColumnIndex());
            copyCell(sourceCell, targetCell);
        }
    }
    private static void copyCell(Cell sourceCell, Cell targetCell) {
        switch (sourceCell.getCellType()) {
            case STRING:
                targetCell.setCellValue(sourceCell.getStringCellValue());
                break;
            case NUMERIC:
                targetCell.setCellValue(sourceCell.getNumericCellValue());
                break;
            case BOOLEAN:
                targetCell.setCellValue(sourceCell.getBooleanCellValue());
                break;
            case FORMULA:
                targetCell.setCellFormula(sourceCell.getCellFormula());
                break;
            default:
                break;
        }
    }
}

四、处理相同的列和行格式

在合并过程中，处理相同的列和行格式是一个关键点。你需要确保在合并时，列和行的格式保持一致。以下是一些处理格式的示例代码：

import org.apache.poi.ss.usermodel.*;
public class ExcelFormatHandler {
    public static void copyCellStyle(Cell sourceCell, Cell targetCell, Workbook targetWorkbook) {
        CellStyle newCellStyle = targetWorkbook.createCellStyle();
        newCellStyle.cloneStyleFrom(sourceCell.getCellStyle());
        targetCell.setCellStyle(newCellStyle);
    }
    public static void copySheet(Sheet sourceSheet, Sheet targetSheet, Workbook targetWorkbook) {
        for (Row sourceRow : sourceSheet) {
            Row targetRow = targetSheet.createRow(sourceRow.getRowNum());
            for (Cell sourceCell : sourceRow) {
                Cell targetCell = targetRow.createCell(sourceCell.getColumnIndex());
                copyCell(sourceCell, targetCell, targetWorkbook);
            }
        }
    }
    public static void copyCell(Cell sourceCell, Cell targetCell, Workbook targetWorkbook) {
        switch (sourceCell.getCellType()) {
            case STRING:
                targetCell.setCellValue(sourceCell.getStringCellValue());
                break;
            case NUMERIC:
                targetCell.setCellValue(sourceCell.getNumericCellValue());
                break;
            case BOOLEAN:
                targetCell.setCellValue(sourceCell.getBooleanCellValue());
                break;
            case FORMULA:
                targetCell.setCellFormula(sourceCell.getCellFormula());
                break;
            default:
                break;
        }
        copyCellStyle(sourceCell, targetCell, targetWorkbook);
    }
}

五、执行合并

最后，执行合并操作。以下是完整的执行代码示例：

import java.io.IOException;
public class Main {
    public static void main(String[] args) {
        String file1 = "path/to/first/excel.xlsx";
        String file2 = "path/to/second/excel.xlsx";
        String outputFile = "path/to/merged/excel.xlsx";
        try {
            ExcelMerger.mergeExcelFiles(file1, file2, outputFile);
            System.out.println("Excel files merged successfully.");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

六、总结

通过以上步骤，你可以在Java中使用Apache POI库将两个Excel文件合并到一起。首先，导入Apache POI库，然后读取两个Excel文件，接着将它们合并到一个工作簿中，并处理相同的列和行格式。最后，通过执行合并操作生成合并后的Excel文件。这种方法不仅高效，而且可以灵活地处理各种Excel格式的文件。