Spring Boot 文件上传与下载的示例代码

server.port=80## MULTIPART (MultipartProperties)# 开启 multipart 上传功能spring.servlet.multipart.enabled=true# 文件写入磁盘的阈值spring.servlet.multipart.file-size-threshold=2KB# 最大文件大小spring.servlet.multipart.max-file-size=200MB# 最大请求大小spring.servlet.multipart.max-request-size=215MB## 文件存储所需参数# 所有通过 REST APIs 上传的文件都将存储在此目录下file.upload-dir=./uploads

import org.springframework.boot.context.properties.ConfigurationProperties;@ConfigurationProperties(prefix = "file")public class FileProperties {  private String uploadDir;  public String getUploadDir() {    return uploadDir;  }  public void setUploadDir(String uploadDir) {    this.uploadDir = uploadDir;  }}

@SpringBootApplication@EnableConfigurationProperties({    FileProperties.class})public class SpringBootFileApplication {  public static void main(String[] args) {    SpringApplication.run(SpringBootFileApplication.class, args);  }}

public class UploadFileResponse {  private String fileName;  private String fileDownloadUri;  private String fileType;  private long size;  public UploadFileResponse(String fileName, String fileDownloadUri, String fileType, long size) {    this.fileName = fileName;    this.fileDownloadUri = fileDownloadUri;    this.fileType = fileType;    this.size = size;  }  // getter and setter ...}

public class FileException extends RuntimeException{  public FileException(String message) {    super(message);  }  public FileException(String message, Throwable cause) {    super(message, cause);  }}

import com.james.sample.file.dto.UploadFileResponse;import com.james.sample.file.service.FileService;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.core.io.Resource;import org.springframework.http.HttpHeaders;import org.springframework.http.MediaType;import org.springframework.http.ResponseEntity;import org.springframework.web.bind.annotation.*;import org.springframework.web.multipart.MultipartFile;import org.springframework.web.servlet.support.ServletUriComponentsBuilder;import javax.servlet.http.HttpServletRequest;import java.io.IOException;import java.util.Arrays;import java.util.List;import java.util.stream.Collectors;@RestControllerpublic class FileController {  private static final Logger logger = LoggerFactory.getLogger(FileController.class);  @Autowired  private FileService fileService;  @PostMapping("/uploadFile")  public UploadFileResponse uploadFile(@RequestParam("file") MultipartFile file){    String fileName = fileService.storeFile(file);    String fileDownloadUri = ServletUriComponentsBuilder.fromCurrentContextPath()        .path("/downloadFile/")        .path(fileName)        .toUriString();    return new UploadFileResponse(fileName, fileDownloadUri,        file.getContentType(), file.getSize());  }  @PostMapping("/uploadMultipleFiles")  public List<UploadFileResponse> uploadMultipleFiles(@RequestParam("files") MultipartFile[] files) {    return Arrays.stream(files)        .map(this::uploadFile)        .collect(Collectors.toList());  }  @GetMapping("/downloadFile/{fileName:.+}")  public ResponseEntity<Resource> downloadFile(@PathVariable String fileName, HttpServletRequest request) {    // Load file as Resource    Resource resource = fileService.loadFileAsResource(fileName);    // Try to determine file's content type    String contentType = null;    try {      contentType = request.getServletContext().getMimeType(resource.getFile().getAbsolutePath());    } catch (IOException ex) {      logger.info("Could not determine file type.");    }    // Fallback to the default content type if type could not be determined    if(contentType == null) {      contentType = "application/octet-stream";    }    return ResponseEntity.ok()        .contentType(MediaType.parseMediaType(contentType))        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=/"" + resource.getFilename() + "/"")        .body(resource);  }}

import com.james.sample.file.exception.FileException;import com.james.sample.file.property.FileProperties;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.core.io.Resource;import org.springframework.core.io.UrlResource;import org.springframework.stereotype.Service;import org.springframework.util.StringUtils;import org.springframework.web.multipart.MultipartFile;import java.io.IOException;import java.net.MalformedURLException;import java.nio.file.Files;import java.nio.file.Path;import java.nio.file.Paths;import java.nio.file.StandardCopyOption;@Servicepublic class FileService {  private final Path fileStorageLocation; // 文件在本地存储的地址  @Autowired  public FileService(FileProperties fileProperties) {    this.fileStorageLocation = Paths.get(fileProperties.getUploadDir()).toAbsolutePath().normalize();    try {      Files.createDirectories(this.fileStorageLocation);    } catch (Exception ex) {      throw new FileException("Could not create the directory where the uploaded files will be stored.", ex);    }  }  /**   * 存储文件到系统   *   * @param file 文件   * @return 文件名   */  public String storeFile(MultipartFile file) {    // Normalize file name    String fileName = StringUtils.cleanPath(file.getOriginalFilename());    try {      // Check if the file's name contains invalid characters      if(fileName.contains("..")) {        throw new FileException("Sorry! Filename contains invalid path sequence " + fileName);      }      // Copy file to the target location (Replacing existing file with the same name)      Path targetLocation = this.fileStorageLocation.resolve(fileName);      Files.copy(file.getInputStream(), targetLocation, StandardCopyOption.REPLACE_EXISTING);      return fileName;    } catch (IOException ex) {      throw new FileException("Could not store file " + fileName + ". Please try again!", ex);    }  }  /**   * 加载文件   * @param fileName 文件名   * @return 文件   */  public Resource loadFileAsResource(String fileName) {    try {      Path filePath = this.fileStorageLocation.resolve(fileName).normalize();      Resource resource = new UrlResource(filePath.toUri());      if(resource.exists()) {        return resource;      } else {        throw new FileException("File not found " + fileName);      }    } catch (MalformedURLException ex) {      throw new FileException("File not found " + fileName, ex);    }  }}

<!DOCTYPE html><html lang="zh-cn"><head>  <!-- Required meta tags -->  <meta charset="UTF-8">  <meta http-equiv="X-UA-Compatible" content="IE=edge">  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">  <title>Spring Boot File Upload / Download Rest API Example</title>  <!-- Bootstrap CSS -->  <link href="/css/main.css" rel="external nofollow" rel="stylesheet"/></head><body><noscript>  <h2>Sorry! Your browser doesn't support Javascript</h2></noscript><div class="upload-container">  <div class="upload-header">    <h2>Spring Boot File Upload / Download Rest API Example</h2>  </div>  <div class="upload-content">    <div class="single-upload">      <h3>Upload Single File</h3>      <form id="singleUploadForm" name="singleUploadForm">        <input id="singleFileUploadInput" type="file" name="file" class="file-input" required/>        <button type="submit" class="primary submit-btn">Submit</button>      </form>      <div class="upload-response">        <div id="singleFileUploadError"></div>        <div id="singleFileUploadSuccess"></div>      </div>    </div>    <div class="multiple-upload">      <h3>Upload Multiple Files</h3>      <form id="multipleUploadForm" name="multipleUploadForm">        <input id="multipleFileUploadInput" type="file" name="files" class="file-input" multiple required/>        <button type="submit" class="primary submit-btn">Submit</button>      </form>      <div class="upload-response">        <div id="multipleFileUploadError"></div>        <div id="multipleFileUploadSuccess"></div>      </div>    </div>  </div></div><!-- Optional JavaScript --><script src="/js/main.js"></script></body></html>

* {  -webkit-box-sizing: border-box;  -moz-box-sizing: border-box;  box-sizing: border-box;}body {  margin: 0;  padding: 0;  font-weight: 400;  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;  font-size: 1rem;  line-height: 1.58;  color: #333;  background-color: #f4f4f4;}body:before {  height: 50%;  width: 100%;  position: absolute;  top: 0;  left: 0;  background: #128ff2;  content: "";  z-index: 0;}.clearfix:after {  display: block;  content: "";  clear: both;}h1, h2, h3, h4, h5, h6 {  margin-top: 20px;  margin-bottom: 20px;}h1 {  font-size: 1.7em;}a {  color: #128ff2;}button {  box-shadow: none;  border: 1px solid transparent;  font-size: 14px;  outline: none;  line-height: 100%;  white-space: nowrap;  vertical-align: middle;  padding: 0.6rem 1rem;  border-radius: 2px;  transition: all 0.2s ease-in-out;  cursor: pointer;  min-height: 38px;}button.primary {  background-color: #128ff2;  box-shadow: 0 2px 2px 0 rgba(0, 0, 0, 0.12);  color: #fff;}input {  font-size: 1rem;}input[type="file"] {  border: 1px solid #128ff2;  padding: 6px;  max-width: 100%;}.file-input {  width: 100%;}.submit-btn {  display: block;  margin-top: 15px;  min-width: 100px;}@media screen and (min-width: 500px) {  .file-input {    width: calc(100% - 115px);  }  .submit-btn {    display: inline-block;    margin-top: 0;    margin-left: 10px;  }}.upload-container {  max-width: 700px;  margin-left: auto;  margin-right: auto;  background-color: #fff;  box-shadow: 0 1px 11px rgba(0, 0, 0, 0.27);  margin-top: 60px;  min-height: 400px;  position: relative;  padding: 20px;}.upload-header {  border-bottom: 1px solid #ececec;}.upload-header h2 {  font-weight: 500;}.single-upload {  padding-bottom: 20px;  margin-bottom: 20px;  border-bottom: 1px solid #e8e8e8;}.upload-response {  overflow-x: hidden;  word-break: break-all;}

'use strict';var singleUploadForm = document.querySelector('#singleUploadForm');var singleFileUploadInput = document.querySelector('#singleFileUploadInput');var singleFileUploadError = document.querySelector('#singleFileUploadError');var singleFileUploadSuccess = document.querySelector('#singleFileUploadSuccess');var multipleUploadForm = document.querySelector('#multipleUploadForm');var multipleFileUploadInput = document.querySelector('#multipleFileUploadInput');var multipleFileUploadError = document.querySelector('#multipleFileUploadError');var multipleFileUploadSuccess = document.querySelector('#multipleFileUploadSuccess');function uploadSingleFile(file) {  var formData = new FormData();  formData.append("file", file);  var xhr = new XMLHttpRequest();  xhr.open("POST", "/uploadFile");  xhr.onload = function() {    console.log(xhr.responseText);    var response = JSON.parse(xhr.responseText);    if(xhr.status == 200) {      singleFileUploadError.style.display = "none";      singleFileUploadSuccess.innerHTML = "<p>File Uploaded Successfully.</p><p>DownloadUrl : <a href='" + response.fileDownloadUri + "' target='_blank'>" + response.fileDownloadUri + "</a></p>";      singleFileUploadSuccess.style.display = "block";    } else {      singleFileUploadSuccess.style.display = "none";      singleFileUploadError.innerHTML = (response && response.message) || "Some Error Occurred";    }  }  xhr.send(formData);}function uploadMultipleFiles(files) {  var formData = new FormData();  for(var index = 0; index < files.length; index++) {    formData.append("files", files[index]);  }  var xhr = new XMLHttpRequest();  xhr.open("POST", "/uploadMultipleFiles");  xhr.onload = function() {    console.log(xhr.responseText);    var response = JSON.parse(xhr.responseText);    if(xhr.status == 200) {      multipleFileUploadError.style.display = "none";      var content = "<p>All Files Uploaded Successfully</p>";      for(var i = 0; i < response.length; i++) {        content += "<p>DownloadUrl : <a href='" + response[i].fileDownloadUri + "' target='_blank'>" + response[i].fileDownloadUri + "</a></p>";      }      multipleFileUploadSuccess.innerHTML = content;      multipleFileUploadSuccess.style.display = "block";    } else {      multipleFileUploadSuccess.style.display = "none";      multipleFileUploadError.innerHTML = (response && response.message) || "Some Error Occurred";    }  }  xhr.send(formData);}singleUploadForm.addEventListener('submit', function(event){  var files = singleFileUploadInput.files;  if(files.length === 0) {    singleFileUploadError.innerHTML = "Please select a file";    singleFileUploadError.style.display = "block";  }  uploadSingleFile(files[0]);  event.preventDefault();}, true);multipleUploadForm.addEventListener('submit', function(event){  var files = multipleFileUploadInput.files;  if(files.length === 0) {    multipleFileUploadError.innerHTML = "Please select at least one file";    multipleFileUploadError.style.display = "block";  }  uploadMultipleFiles(files);  event.preventDefault();}, true);