SpringBoot 文件上传和下载的实现源码

SpringBoot 文件上传和下载的实现源码

本篇文章介绍SpringBoot的上传和下载功能。

一、创建SpringBoot工程，添加依赖

compile("org.springframework.boot:spring-boot-starter-web")

compile("org.springframework.boot:spring-boot-starter-thymeleaf")

工程目录为：

Application.java 启动类

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);

}

}

二、创建测试页面

在resources/templates目录下新建uploadForm.html

三、新建StorageService服务

StorageService接口

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 loadAll();

Path load(String filename);

Resource loadAsResource(String filename);

void deleteAll();

}

StorageService实现

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");

/**

* 保存文件

*

* @param file 文件

*/

@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);

}

}

/**

* 列出upload-dir下面所有文件

* @return

*/

@Override

public Stream loadAll()

{

try

{

return Files.walk(this.rootLocation, 1) //path -> !path.equals(this.rootLocation)

.filter(new Predicate()

{

@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);

}

/**

* 获取文件资源

* @param filename 文件名

* @return Resource

*/

@Override

public Resource loadAsResource(String filename)

{

try

{

Path file = load(filename);

Resource resource = new UrlResource(file.toUri());

if (resource.exists() || resource.isReadEILsCqlPXable())

{

return resource;

}

else

{

throw new StorageFileNotFoundException("Could not read file: " + filename);

}

}

catch (MalformedURLException e)

{

throw new StorageFileNotFoundException("Could not read file: " + filename, e);

}

}

/**

* 删除upload-dir目录所有文件

*/

@Override

public void deleteAll()

{

FileSystemUtils.deleteRecursively(rootLocation.toFile());

}

/**

* 初始化

*/

@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.java

package hello.storage;

public class StorageFileNotFoundException extends StorageException {

public StorageFileNotFoundException(String message) {

super(message);

}

public StorageFileNotFoundException(String message, Throwable cause) {

super(message, cause);

}

}

四、Controller创建

将上传的文件，放到工程的upload-dir目录，默认在界面上列出可以下载的文件。

listUploadedFiles函数，会列出当前目录下的所有文件

serveFile下载文件

handleFileUpload上传文件

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 StorageServihttp://ce 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 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();

}

}

源码下载：https://github.com/HelloKittyNII/SpringBoot/tree/master/SpringBootUploadAndDownload

总结

以上所述是给大家介绍的SpringBoot 文件上传和下载的实现源码，希望对大家有所帮助，如果大家有任何疑问请给我留言，会及时回复大家的。在此也非常感谢大家对我们网站的支持！

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