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();
}
}