基于spring web实现简单分片上传demo

基于spring web实现简单分片上传demo

我的场景：调用三方系统一直…报错，为了了解分片，自己写一个分片、从而大概猜测是谁的问题。

controller

import org.springframework.web.bind.annotation.*; import org.springframework.web.multipart.MultipartFile; import java.io.*; import java.nio.file.*; import java.util.Arrays; import java.util.Comparator; import java.util.stream.Stream; // 必须导入这个 @RestController @RequestMapping("/upload") @CrossOrigin public class ChunkUploadController { private static final String UPLOAD_DIR = "upload_data"; @PostMapping("/chunk") public String uploadChunk(@RequestParam("file") MultipartFile file, @RequestParam("chunkNumber") int chunkNumber, @RequestParam("totalChunks") int totalChunks, @RequestParam("identifier") String identifier, @RequestParam("filename") String filename) throws IOException { // 【关键修改】使用 toAbsolutePath() 获取绝对路径 Path chunkDir = Paths.get(UPLOAD_DIR, "temp", identifier).toAbsolutePath(); if (!Files.exists(chunkDir)) { Files.createDirectories(chunkDir); } Path chunkPath = chunkDir.resolve("chunk-" + chunkNumber); file.transferTo(chunkPath.toFile()); System.out.println("收到分片: " + chunkNumber + " / " + totalChunks); if (isAllChunksUploaded(chunkDir, totalChunks)) { return mergeChunks(chunkDir, filename, identifier); } return "Chunk " + chunkNumber + " uploaded."; } /** * JDK 8 修正版：将 var 替换为 Stream<Path> */ private boolean isAllChunksUploaded(Path chunkDir, int totalChunks) { // Files.list 返回的是 Stream<Path>，且实现了 AutoCloseable，需要 try-with-resources 关闭流 try (Stream<Path> list = Files.list(chunkDir)) { return list.count() == totalChunks; } catch (IOException e) { return false; } } private String mergeChunks(Path chunkDir, String filename, String identifier) throws IOException { System.out.println("所有分片已接收，开始合并..."); Path targetFile = Paths.get(UPLOAD_DIR, "final", identifier + "_" + filename); if (!Files.exists(targetFile.getParent())) { Files.createDirectories(targetFile.getParent()); } File[] chunks = chunkDir.toFile().listFiles(); if (chunks != null) { // JDK 8 写法：Comparator Arrays.sort(chunks, new Comparator<File>() { @Override public int compare(File o1, File o2) { String name1 = o1.getName(); String name2 = o2.getName(); int n1 = Integer.parseInt(name1.substring(name1.lastIndexOf("-") + 1)); int n2 = Integer.parseInt(name2.substring(name2.lastIndexOf("-") + 1)); return Integer.compare(n1, n2); } }); // 合并文件 try (OutputStream out = new BufferedOutputStream(Files.newOutputStream(targetFile, StandardOpenOption.CREATE, StandardOpenOption.APPEND))) { for (File chunk : chunks) { Files.copy(chunk.toPath(), out); } } } System.out.println("合并完成: " + targetFile.toString()); // 合并完成后清理临时目录（可选） // deleteDirectory(chunkDir.toFile()); return "File uploaded and merged successfully: " + targetFile.toString(); } }

调用客户端client代码

import org.springframework.core.io.FileSystemResource; import org.springframework.http.HttpEntity; import org.springframework.http.HttpHeaders; import org.springframework.http.MediaType; import org.springframework.util.LinkedMultiValueMap; import org.springframework.util.MultiValueMap; import org.springframework.web.client.RestTemplate; import java.io.*; import java.util.UUID; public class ChunkUploadClient { private static final String UPLOAD_URL = "http://localhost:8080/upload/chunk"; private static final int CHUNK_SIZE = 20 * 1024 * 1024; // 定义分片大小: 2MB public static void main(String[] args) { // 1. 准备要上传的文件 (请修改为你电脑上真实存在的文件路径) File sourceFile = new File("C:\\Users\\qinqin\\Desktop\\附件落地测试\\test.zip"); if (!sourceFile.exists()) { System.err.println("测试文件不存在，请修改路径！"); return; } // 2. 计算总分片数 long fileSize = sourceFile.length(); int totalChunks = (int) Math.ceil((double) fileSize / CHUNK_SIZE); // 生成一个唯一标识，代表这次上传任务 String identifier = UUID.randomUUID().toString(); String filename = sourceFile.getName(); System.out.println("开始上传文件: " + filename); System.out.println("文件大小: " + fileSize + " bytes, 总分片数: " + totalChunks); RestTemplate restTemplate = new RestTemplate(); // 3. 开始切片并上传 try (RandomAccessFile raf = new RandomAccessFile(sourceFile, "r")) { byte[] buffer = new byte[CHUNK_SIZE]; int bytesRead; int chunkNumber = 1; while ((bytesRead = raf.read(buffer)) != -1) { // 如果是最后一片，可能不满CHUNK_SIZE，需要截取 if (bytesRead < CHUNK_SIZE) { byte[] temp = new byte[bytesRead]; System.arraycopy(buffer, 0, temp, 0, bytesRead); uploadChunk(restTemplate, temp, chunkNumber, totalChunks, identifier, filename); } else { uploadChunk(restTemplate, buffer, chunkNumber, totalChunks, identifier, filename); } chunkNumber++; } } catch (Exception e) { e.printStackTrace(); } } private static void uploadChunk(RestTemplate restTemplate, byte[] fileBytes, int chunkNumber, int totalChunks, String identifier, String filename) throws IOException { // 构造临时文件用于封装进 MultipartFile (RestTemplate 需要 Resource) // 在实际生产的Client中，通常不需要落盘，直接用 ByteArrayResource， // 但为了模拟名为"file"的文件流，这里创建临时文件是最通用的做法 File tempChunkFile = File.createTempFile("client-chunk-", ".tmp"); try (FileOutputStream fos = new FileOutputStream(tempChunkFile)) { fos.write(fileBytes); } // 构造请求体 MultiValueMap<String, Object> body = new LinkedMultiValueMap<>(); body.add("file", new FileSystemResource(tempChunkFile)); body.add("chunkNumber", chunkNumber); body.add("totalChunks", totalChunks); body.add("identifier", identifier); body.add("filename", filename); HttpHeaders headers = new HttpHeaders(); headers.setContentType(MediaType.MULTIPART_FORM_DATA); HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(body, headers); // 发送请求 String response = restTemplate.postForObject(UPLOAD_URL, requestEntity, String.class); System.out.println("分片 " + chunkNumber + " 响应: " + response); // 清理客户端临时文件 tempChunkFile.delete(); } }