SpringBoot 檔案上傳與下載 

<!DOCTYPE html>
<html lang="zh" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>文件上传和下载</title>
</head>
<body>
<form th:action="@{/upload}" method="post" enctype="multipart/form-data">
    <p>
        <label for="file1" >请选择要上传的文件</label>
        <input type="file" id="file1" name="file" multiple/>
    </p>
    <p>
        <input type="submit" value="上传">
    </p>
</form>
<ul>
    <li  th:each="file : ${files}">
        <a th:href="@{/download(fileName=${file})}" th:text="${file}"></a>
    </li>
</ul>
</body>
</html>
 package com.sun.ch04.controller;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;

import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.List;
import org.apache.commons.io.FileUtils;

@Controller
public class FileController {
    @GetMapping("/upload")
    public String doUpload(Model model) {
        // 将上传文件目录下的所有文件名列出来，保存到模型对象中
        String uploadPath = "C:" + File.separator + "SpringBootUpload";
        File dir = new File(uploadPath);
        model.addAttribute("files", dir.list());
        return "upload";
    }

    @PostMapping("/upload")
    @ResponseBody
    public String upload(HttpServletRequest request) {
        // 得到所有文件的列表
        List<MultipartFile> files = ((MultipartHttpServletRequest) request).getFiles("file");
        String uploadPath = "C:" + File.separator + "SpringBootUpload";
        File dir = new File(uploadPath);

        // 如果保存上传文件的目录不存在，则创建它
        if (!dir.exists()) {
            dir.mkdirs();
        }
        for (MultipartFile f : files) {
            if (f.isEmpty()) {
                continue;
            }
            File target = new File(uploadPath + File.separator + f.getOriginalFilename());
            try {
                f.transferTo(target);
            } catch (IllegalStateException | IOException e) {
                e.printStackTrace();
            }
        }
        return "文件上传成功！";
    }

    @GetMapping("/download")
    public ResponseEntity<byte[]> download(@RequestParam String fileName) throws IOException {
        String dir = "C:" + File.separator + "SpringBootUpload";
        String fileFullPath = dir + File.separator + fileName;
        File file = new File(fileFullPath);

        ResponseEntity.BodyBuilder builder = ResponseEntity.ok();
        builder.contentLength(file.length());
        builder.contentType(MediaType.APPLICATION_OCTET_STREAM);
        fileName = new String(fileName.getBytes(StandardCharsets.UTF_8),StandardCharsets.ISO_8859_1);
        builder.header("Content-Disposition", "attachment; filename=" + fileName);
        return builder.body(FileUtils.readFileToByteArray(file));
    }

}
張貼者： 於