This article introduces the upload and download functions of SpringBoot.
1. Create SpringBoot project and add dependencies
compile("org.springframework.boot:spring-boot-starter-web") compile("org.springframework.boot:spring-boot-starter-thymeleaf")The project directory is:
Application.java startup class
package hello; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.context.properties.EnableConfigurationProperties; @SpringBootApplication public class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); } }2. Create a test page
Create a new uploadForm.html in the resources/templates directory
<html xmlns:th="http://www.thymeleaf.org"> <body> <div th:if="${message}"> <h2 th:text="${message}"/> </div> <div> <form method="POST" enctype="multipart/form-data" action="/"> <table> <tr><td>File to upload:</td><td><input type="file" name="file" /></td></tr> <tr><td></td><td><input type="submit" value="Upload" /></td></tr> </table> </form> </div> <div> <ul> <li th:each="file : ${files}"> <a th:href="${file}" rel="external nofollow" th:text="${file}" /> </li> </ul> </div> </body> </html>3. Create a new StorageService service
StorageService interface
package hello.storage; import org.springframework.core.io.Resource; import org.springframework.web.multipart.MultipartFile; import java.nio.file.Path; import java.util.stream.Stream; public interface StorageService { void init(); void store(MultipartFile file); Stream<Path> loadAll(); Path load(String filename); Resource loadAsResource(String filename); void deleteAll(); }StorageService implementation
package hello.storage; import org.springframework.core.io.Resource; import org.springframework.core.io.UrlResource; import org.springframework.stereotype.Service; import org.springframework.util.FileSystemUtils; 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; import java.util.function.Predicate; import java.util.stream.Stream; @Service public class FileSystemStorageService implements StorageService { private final Path rootLocation = Paths.get("upload-dir"); /** * Save file* * @param file file*/ @Override public void store(MultipartFile file) { String filename = StringUtils.cleanPath(file.getOriginalFilename()); try { if (file.isEmpty()) { throw new StorageException("Failed to store empty file " + filename); } if (filename.contains("..")) { // This is a security check throw new StorageException("Cannot store file with relative path outside current directory " + filename); } Files.copy(file.getInputStream(), this.rootLocation.resolve(filename), StandardCopyOption.REPLACE_EXISTING); } catch (IOException e) { throw new StorageException("Failed to store file " + filename, e); } } /** * List all files below upload-dir* @return */ @Override public Stream<Path> loadAll() { try { return Files.walk(this.rootLocation, 1) //path -> !path.equals(this.rootLocation) .filter(new Predicate<Path>() { @Override public boolean test(Path path) { return !path.equals(rootLocation); } }); } catch (IOException e) { throw new StorageException("Failed to read stored files", e); } } @Override public Path load(String filename) { return rootLocation.resolve(filename); } /** * Get file resources* @param filename File name* @return Resource */ @Override public Resource loadAsResource(String filename) { try { Path file = load(filename); Resource resource = new UrlResource(file.toUri()); if (resource.exists() || resource.isReadable()) { return resource; } else { throw new StorageFileNotFoundException("Could not read file: " + filename); } } catch (MalformedURLException e) { throw new StorageFileNotFoundException("Could not read file: " + filename, e); } } /** * Delete all files in the upload-dir directory*/ @Override public void deleteAll() { FileSystemUtils.deleteRecursively(rootLocation.toFile()); } /** * Initialization*/ @Override public void init() { try { Files.createDirectories(rootLocation); } catch (IOException e) { throw new StorageException("Could not initialize storage", e); } } }StorageException.java
package hello.storage; public class StorageException extends RuntimeException { public StorageException(String message) { super(message); } public StorageException(String message, Throwable cause) { super(message, cause); } } StorageFileNotFoundException.javapackage hello.storage; public class StorageFileNotFoundException extends StorageException { public StorageFileNotFoundException(String message) { super(message); } public StorageFileNotFoundException(String message, Throwable cause) { super(message, cause); } }4. Controller creation
Put the uploaded files in the project's upload-dir directory, and list the downloadable files on the interface by default.
listUploadedFiles function will list all files in the current directory
serveFile download file
handleFileUpload upload file
package hello; import java.io.IOException; import java.util.stream.Collectors; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.core.io.Resource; import org.springframework.http.HttpHeaders; import org.springframework.http.ResponseEntity; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.ExceptionHandler; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.ResponseBody; import org.springframework.web.multipart.MultipartFile; import org.springframework.web.servlet.mvc.method.annotation.MvcUriComponentsBuilder; import org.springframework.web.servlet.mvc.support.RedirectAttributes; import hello.storage.StorageFileNotFoundException; import hello.storage.StorageService; @Controller public class FileUploadController { private final StorageService storageService; @Autowired public FileUploadController(StorageService storageService) { this.storageService = storageService; } @GetMapping("/") public String listUploadedFiles(Model model) throws IOException { model.addAttribute("files", storageService.loadAll().map( path -> MvcUriComponentsBuilder.fromMethodName(FileUploadController.class, "serveFile", path.getFileName().toString()).build().toString()) .collect(Collectors.toList())); return "uploadForm"; } @GetMapping("/files/{filename:.+}") @ResponseBody public ResponseEntity<Resource> serveFile(@PathVariable String filename) { Resource file = storageService.loadAsResource(filename); return ResponseEntity.ok().header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=/"" + file.getFilename() + "/"").body(file); } @PostMapping("/") public String handleFileUpload(@RequestParam("file") MultipartFile file, RedirectAttributes redirectAttributes) { storageService.store(file); redirectAttributes.addFlashAttribute("message", "You successfully uploaded " + file.getOriginalFilename() + "!"); return "redirect:/"; } @ExceptionHandler(StorageFileNotFoundException.class) public ResponseEntity<?> handleStorageFileNotFound(StorageFileNotFoundException exc) { return ResponseEntity.notFound().build(); } } Source code download: https://github.com/HelloKittyNII/SpringBoot/tree/master/SpringBootUploadAndDownload
Summarize
The above is the source code for uploading and downloading SpringBoot files introduced to you by the editor. I hope it will be helpful to you. If you have any questions, please leave me a message and the editor will reply to you in time. Thank you very much for your support to Wulin.com website!