项目场景：

element的table上传文件并渲染出文件名称点击所属行可以查看文件,并且可以导出合并文件,此文章是记录合并文档前端展示的帖子

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解决方案：

后端定义三个工具类
分别是pdf,doc和word的excle的目前我没整
 

word的工具类

package com.sc.modules.biddinvestment.utils;

import org.apache.poi.xwpf.usermodel.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

public class WordMerger {
    private static final Logger logger = LoggerFactory.getLogger(WordMerger.class);

    public String mergeWordDocuments(List<String> filePaths) throws IOException {
        validateFiles(filePaths);
        XWPFDocument mergedDoc = new XWPFDocument();

        try {
            for (String filePath : filePaths) {
                addFileToDocument(mergedDoc, filePath);
            }
            return saveMergedDocument(mergedDoc);
        } finally {
            mergedDoc.close();
        }
    }

    private void addFileToDocument(XWPFDocument mergedDoc, String filePath) throws IOException {
        File file = new File(filePath);
        addSectionTitle(mergedDoc, file.getName());

        if (filePath.toLowerCase().endsWith(".txt")) {
            addTxtContent(mergedDoc, file);
        } else if (filePath.toLowerCase().endsWith(".docx")) {
            addDocxContent(mergedDoc, file);
        } else {
            throw new IllegalArgumentException("暂不支持的文件格式: " + filePath);
        }
    }

    private void addSectionTitle(XWPFDocument doc, String fileName) {
        XWPFParagraph titlePara = doc.createParagraph();
        titlePara.setAlignment(ParagraphAlignment.CENTER);
        XWPFRun titleRun = titlePara.createRun();
//        titleRun.setText("===== 文件: " + fileName + " ====="); //添加上之后文档名称会出现在合并后的文档里
        titleRun.setFontSize(14);
        titleRun.setBold(true);
        titleRun.addBreak();
    }

    private void addTxtContent(XWPFDocument doc, File txtFile) throws IOException {
        List<String> lines = Files.readAllLines(txtFile.toPath());
        XWPFParagraph para = doc.createParagraph();
        XWPFRun run = para.createRun();
        for (String line : lines) {
            run.setText(line);
            run.addBreak();
        }
        run.addBreak(); // 段落间隔
    }

    private void addDocxContent(XWPFDocument mergedDoc, File docxFile) throws IOException {
        try (XWPFDocument sourceDoc = new XWPFDocument(new FileInputStream(docxFile))) {
            for (XWPFParagraph para : sourceDoc.getParagraphs()) {
                XWPFParagraph newPara = mergedDoc.createParagraph();
                newPara.getCTP().set(para.getCTP()); // 复制段落格式
            }
            for (XWPFTable table : sourceDoc.getTables()) {
                mergedDoc.createTable().getCTTbl().set(table.getCTTbl()); // 复制表格
            }
        }
    }

    private String saveMergedDocument(XWPFDocument doc) throws IOException {
        Path desktopPath = Paths.get(System.getProperty("user.home"), "Desktop");
        if (!Files.exists(desktopPath)) Files.createDirectories(desktopPath);

        String timestamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        Path outputPath = desktopPath.resolve("merged_word_" + timestamp + ".docx");

        try (FileOutputStream fos = new FileOutputStream(outputPath.toFile())) {
            doc.write(fos);
        }
        logger.info("Word合并完成，输出路径: {}", outputPath);
        return outputPath.toString();
    }

    private void validateFiles(List<String> filePaths) {
        for (String path : filePaths) {
            File file = new File(path);
            if (!file.exists() || !file.canRead()) {
                throw new IllegalArgumentException("文件无效或不可读: " + path);
            }
        }
    }
}

 doc的工具类

package com.sc.modules.biddinvestment.utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.BufferedWriter;
import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

public class DocMerger {
    private static final Logger logger = LoggerFactory.getLogger(DocMerger.class);

    // 保留原文本合并功能（可选）
    public String mergeTxtDocuments(List<String> filePaths) throws IOException {
        validateFiles(filePaths);
        Path desktopPath = Paths.get(System.getProperty("user.home"), "Desktop");
        if (!Files.exists(desktopPath)) Files.createDirectories(desktopPath);

        String timestamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        Path outputPath = desktopPath.resolve("merged_txt_" + timestamp + ".txt");

        try (BufferedWriter writer = Files.newBufferedWriter(outputPath, StandardCharsets.UTF_8)) {
            for (String path : filePaths) {
                File file = new File(path);
                writer.write("===== 文件: " + file.getName() + " =====\n");
                List<String> lines = Files.readAllLines(file.toPath(), StandardCharsets.UTF_8);
                for (String line : lines) {
                    writer.write(line);
                    writer.newLine();
                }
                writer.write("\n\n");
            }
        }
        logger.info("文本合并完成，输出路径: {}", outputPath);
        return outputPath.toString();
    }

    private void validateFiles(List<String> filePaths) {
        for (String path : filePaths) {
            File file = new File(path);
            if (!file.exists() || !file.canRead()) {
                throw new IllegalArgumentException("文件无效或不可读: " + path);
            }
        }
    }
}

pdf的 

package com.sc.modules.biddinvestment.utils;
import org.apache.pdfbox.multipdf.PDFMergerUtility;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.stream.Collectors;

public class PdfMerger {
    private static final Logger logger = LoggerFactory.getLogger(PdfMerger.class);
    private static final String DEFAULT_OUTPUT_NAME = "merged";
    private static final String PDF_EXTENSION = ".pdf";

    /**
     * 合并多个PDF文件
     *
     * @param filePaths 要合并的PDF文件路径列表
     * @return 合并后的文件绝对路径
     * @throws IOException 如果合并过程中发生错误
     */
    public String mergePdfs(List<String> filePaths) throws IOException {
        validateInputFiles(filePaths);
        File outputFile = prepareOutputFile();
        mergeFiles(filePaths, outputFile);
        logger.info("成功合并 {} 个PDF文件到: {}", filePaths.size(), outputFile.getAbsolutePath());
        return outputFile.getAbsolutePath();
    }

    /**
     * 验证输入文件
     */
    private void validateInputFiles(List<String> filePaths) {
        if (filePaths == null || filePaths.isEmpty()) {
            throw new IllegalArgumentException("文件路径列表不能为空");
        }

        for (String path : filePaths) {
            if (path == null || path.trim().isEmpty()) {
                throw new IllegalArgumentException("文件路径不能为空");
            }

            File file = new File(path);
            if (!file.exists()) {
                throw new IllegalArgumentException("文件不存在: " + path);
            }
            if (!file.isFile()) {
                throw new IllegalArgumentException("路径不是文件: " + path);
            }
            if (!file.canRead()) {
                throw new IllegalArgumentException("文件不可读: " + path);
            }
            if (!path.toLowerCase().endsWith(".pdf")) {
                throw new IllegalArgumentException("仅支持PDF文件: " + path);
            }
        }
    }

    /**
     * 准备输出文件
     */
    private File prepareOutputFile() throws IOException {
        Path desktopPath = Paths.get(System.getProperty("user.home"), "Desktop");

        // 确保桌面目录存在
        if (!Files.exists(desktopPath)) {
            logger.warn("桌面目录不存在，尝试创建: {}", desktopPath);
            try {
                Files.createDirectories(desktopPath);
            } catch (IOException e) {
                throw new IOException("无法创建桌面目录: " + desktopPath, e);
            }
        }

        // 生成唯一文件名
        String timestamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        String baseName = DEFAULT_OUTPUT_NAME + "_" + timestamp + PDF_EXTENSION;

        Path outputPath = desktopPath.resolve(baseName);

        // 处理文件名冲突
        int counter = 1;
        while (Files.exists(outputPath)) {
            baseName = DEFAULT_OUTPUT_NAME + "_" + timestamp + "_" + counter + PDF_EXTENSION;
            outputPath = desktopPath.resolve(baseName);
            counter++;
        }

        return outputPath.toFile();
    }

    /**
     * 执行PDF合并
     */
    private void mergeFiles(List<String> inputFilePaths, File outputFile) throws IOException {
        PDFMergerUtility merger = new PDFMergerUtility();

        try {
            // 添加所有源文件
            for (String filePath : inputFilePaths) {
                merger.addSource(new File(filePath));
            }

            // 设置输出文件
            merger.setDestinationFileName(outputFile.getAbsolutePath());

            // 执行合并
            merger.mergeDocuments(null);
        } catch (IOException e) {
            // 合并失败时删除可能已创建的部分输出文件
            if (outputFile.exists() && !outputFile.delete()) {
                logger.error("无法删除部分合并的文件: {}", outputFile.getAbsolutePath());
            }
            throw new IOException("PDF合并失败: " + e.getMessage(), e);
        }
    }

    // 重载方法，支持可变参数
    public String mergePdfs(String... filePaths) throws IOException {
        return mergePdfs(Arrays.asList(filePaths));
    }

}

调用方法 

@PostMapping("/mergeDocuments")
public String mergeFiles(@RequestBody Map<String, List<String>> request) {
    try {
        List<String> filePaths = request.get("filePaths");
        if (filePaths == null || filePaths.isEmpty()) {
            return "错误：文件路径列表为空！";
        }

        boolean allPdf = filePaths.stream()
                .allMatch(path -> path.toLowerCase().endsWith(".pdf"));

        String mergedFilePath;
        if (allPdf) {
            PdfMerger merger = new PdfMerger();
            mergedFilePath = merger.mergePdfs(filePaths);
        } else {
            WordMerger wordMerger = new WordMerger();
            mergedFilePath = wordMerger.mergeWordDocuments(filePaths);
        }

        return "文件合并成功，保存路径: " + mergedFilePath;
    } catch (Exception e) {
        return "文件合并失败：" + e.getMessage();
    }
}

前端:
 

getMenuData() {
  setTimeout(() => {
    url.getMenusTree().then(res => {
      // 定义文件类型映射
      const fileTypeMap = {
        pdf: 'PDF文件',
        doc: 'Word文件',
        docx: 'Word文件',
        xls: 'Excel文件',
        xlsx: 'Excel文件'
      };
      // 提取文件后缀的工具函数
      const getFileType = (filepatch, filecode) => {
        if (filepatch) {
          const ext = filepatch.split('.').pop().toLowerCase();
          return fileTypeMap[ext] || '目录';
        }
        // fallback 用 filecode 判断
        return filecode === 0 ? '目录' : '目录';
      };
      // 定义递归处理函数
      const processTree = (nodes) => {
        return nodes.map(item => ({
          ...item,
          filetype: getFileType(item.filepatch, item.filecode),
          children: item.children ? processTree(item.children) : []
        }));
      };
      // 处理后的树结构赋值
      this.biddData = processTree(res.data);
    });
  }, 100);
},

前端定义递归方法遍历每条数据的filepatch 然后利用

filepatch.split('.').pop().toLowerCase();
获取名称的拓展名判断是哪一类
之后调用fileTypeMap将对应的文件名称写进去
就可以展示了
我这里是树形结构所以调用了processTree