使用Apache POI Java将多个excel文件合并为一个excel文件

问题描述

我有100个excel文件，我想将它们全部合并到一个excel文件中。在我的示例中，我有2个excel文件，我想将它们合并为一个。我做不到我正在使用Apache POI API。 在一个excel工作簿中，也可以有多个工作表，因此我也要遍历每个工作簿的工作表。 我尝试了研究，但获得了此链接，但对我不起作用 https://dev.to/eiceblue/merge-excel-files-in-java-2lo2#:~:text=A%20quick%20way%20to%20merge,data%20table%20into%20another%20worksheet。

请在这里帮助我。

package com.cas.ExcelTest;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Iterator;

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

public class Combine {

    public static void main(String args[]) {
        
        String[] files = new String[] {"Test2.xlsx","Test3.xlsx"};
        XSSFWorkbook workbook = new XSSFWorkbook();     
        try {
            for (int f = 0; f < files.length; f++) {    
                String file = files[f];
                FileInputStream inputStream = new FileInputStream(file);
                XSSFWorkbook tempWorkbook = new XSSFWorkbook(inputStream);
                          
                int numOfSheets = tempWorkbook.getNumberOfSheets();
                    
                for (int i = 0; i < numOfSheets; i++) {
                    XSSFSheet tempSheet = tempWorkbook.getSheetAt(i);
                    String newSheetName = ""+f+""+tempSheet.getSheetName();
                    XSSFSheet sheet = workbook.createSheet(newSheetName);
                    Iterator<Row> itRow = tempSheet.rowIterator();
                
                    while(itRow.hasNext()) {
                        Row tempRow = itRow.next();
                        XSSFRow row = sheet.createRow(tempRow.getRowNum());
                        Iterator<Cell> itCell = tempRow.cellIterator();
                    
                        while(itCell.hasNext()) {
                            Cell tempCell = itCell.next();
                            XSSFCell cell = row.createCell(tempCell.getColumnIndex());
                        
                        switch (tempCell.getCellType()) {
                        case NUMERIC:
                            cell.setCellValue(tempCell.getNumericCellValue());
                            break;
                        case STRING:
                            cell.setCellValue(tempCell.getStringCellValue());
                            break;
                        case BLANK:
                            break;
                        case BOOLEAN:
                            break;
                        case ERROR:
                            break;
                        case FORMULA:
                            cell.setCellValue(tempCell.getNumericCellValue());
                            break;
                        case _NONE:
                            break;
                        default:
                            break;
                    }
                        }       
                    }       
                }
            }
        } catch (IOException ex1) {
            System.out.println("Error reading file");
            ex1.printstacktrace();
        }
            
        try (FileOutputStream outputStream = new FileOutputStream("result.xlsx")) {
            workbook.write(outputStream);
        }
        catch(Exception ex) {
            System.out.println("Something went wrong");
        }
    }
}

我的Excel文件：

Test2.xlsx

Test3.xlsx

在Test3.xlsx和这两个文件中，有些列是多余的，正如您在标题行中看到的那样，它的所有字符串都包含在其中，但之后都有数字值。

解决方法

在这里，您可以大致了解所需的代码，对其进行格式化，将方法的功能提取出来并检查工作表的命名。

String[] files = new String[] {"Test2.xlsx","Test3.xlsx"};
XSSFWorkbook workbook = new XSSFWorkbook();
XSSFSheet sheet = createSheetWithHeader(workbook);
    
try {
    for (int f = 0; f < files.length; f++) {
        String file = files[f];
        FileInputStream inputStream = new FileInputStream(file);
        XSSFWorkbook tempWorkbook = new XSSFWorkbook(inputStream);
            
        int numOfSheets = tempWorkbook.getNumberOfSheets();
            
        for (int i = 0; i < numOfSheets; i++) {
            XSSFSheet tempSheet = tempWorkbook.getSheetAt(i);
                
            int indexLastDataInserted = sheet.getLastRowNum();
            int firstDataRow = getFirstDataRow(tempSheet);
                                
            Iterator<Row> itRow = tempSheet.rowIterator();
            
            while(itRow.hasNext()) {
                Row tempRow = itRow.next();
                
                if (tempRow.getRowNum() >= firstDataRow) {
                    XSSFRow row = sheet.createRow(indexLastDataInserted + 1);
                    
                    Iterator<Cell> itCell = tempRow.cellIterator();
                    
                    while(itCell.hasNext()) {
                        Cell tempCell = itCell.next();
                        XSSFCell cell = row.createCell(tempCell.getColumnIndex());
                        //At this point you will have to set the value of the cell depending on the type of data it is
                        switch (tempCell.getCellType()) {
                            case NUMERIC:
                                cell.setCellValue(tempCell.getNumericCellValue());
                                break;
                            case STRING:
                                cell.setCellValue(tempCell.getStringCellValue());
                                break;
                            /**
                             * Add your other types,here is your problem!!!!!
                             */
                        }
                    }
                }                   
            }
        }
    } 
}catch (IOException ex1) {
    System.out.println("Error reading file");
    ex1.printStackTrace();
}
    
try (FileOutputStream outputStream = new FileOutputStream("result.xlsx")) {
    workbook.write(outputStream);
}

获取第一个数据行的功能（避免必须手动输入每个excel标头结束的位置）

/**
 * If the tab has a filter,it returns the row index of the filter + 1,otherwise it returns 0
 * @param tempSheet
 * @return index of first data row
 */
public static Integer getFirstDataRow(XSSFSheet tempSheet) {
    Integer result = 0;
    Boolean isAutoFilter = tempSheet.getCTWorksheet().isSetAutoFilter();
    
    if (isAutoFilter) {
        String autoFilterRef = tempSheet.getCTWorksheet().getAutoFilter().getRef();
        
        result = new CellReference(autoFilterRef.substring(0,autoFilterRef.indexOf(":"))).getRow() + 1;
    }
    return result;
}

在方法中使用标题创建工作表：

public static XSSFSheet createSheetWithHeader(XSSFWorkbook workbook){
    XSSFSheet sheet = workbook.createSheet("NEW_SHEET_NAME");

    //Implement the header
    [...]

    return sheet;
}