第一个 Spring Boot 程序 : 文件上传

文档地址 https://spring.io/guides/gs/uploading-files/

	4.0.0
	com.zlf
	web
	0.0.1-SNAPSHOT

	
		org.springframework.boot
		spring-boot-starter-parent
		1.4.3.RELEASE
	

	
		1.8
	

	
		
		
		
			org.springframework.boot
			spring-boot-starter-web
		
		
		
		
			org.springframework.boot
			spring-boot-starter-jdbc
		
		
			com.h2database
			h2
		
		
		
		
            org.springframework.boot
            spring-boot-starter-thymeleaf
        
        
            org.springframework.boot
            spring-boot-devtools
            true
        
        
            org.springframework.boot
            spring-boot-configuration-processor
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
		
		
		
		    com.google.guava
		    guava
		    20.0
		
	

	
		
			
				org.springframework.boot
				spring-boot-maven-plugin
			
		
	

Application.java

package com.lzf.upload;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
@EnableConfigurationProperties(StorageProperties.class)
public class Application {

	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}

	@Bean
	CommandLineRunner init(StorageService storageService) {
		return (args) -> {
            storageService.deleteAll();
            storageService.init();
		};
	}
}

FileUploadController.java

package com.lzf.upload;

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.*;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.mvc.method.annotation.MvcUriComponentsBuilder;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;

import java.io.IOException;
import java.util.stream.Collectors;

@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 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();
	}

}

StorageService.java

package com.lzf.upload;

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();

}

FileSystemStorageService

package com.lzf.upload;

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.FileSystemUtils;
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.util.stream.Stream;

@Service
public class FileSystemStorageService implements StorageService {

	private final Path rootLocation;

	@Autowired
	public FileSystemStorageService(StorageProperties properties) {
		this.rootLocation = Paths.get(properties.getLocation());
	}

	@Override
	public void store(MultipartFile file) {
		try {
			if (file.isEmpty()) {
				throw new StorageException("Failed to store empty file " + file.getOriginalFilename());
			}
			Files.copy(file.getInputStream(), this.rootLocation.resolve(file.getOriginalFilename()));
		} catch (IOException e) {
			throw new StorageException("Failed to store file " + file.getOriginalFilename(), e);
		}
	}

	@Override
	public Stream loadAll() {
		try {
			return Files.walk(this.rootLocation, 1).filter(path -> !path.equals(this.rootLocation)).map(path -> this.rootLocation.relativize(path));
		} catch (IOException e) {
			throw new StorageException("Failed to read stored files", e);
		}

	}

	@Override
	public Path load(String filename) {
		return rootLocation.resolve(filename);
	}

	@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);
		}
	}

	@Override
	public void deleteAll() {
		FileSystemUtils.deleteRecursively(rootLocation.toFile());
	}

	@Override
	public void init() {
		try {
			Files.createDirectory(rootLocation);
		} catch (IOException e) {
			throw new StorageException("Could not initialize storage", e);
		}
	}
}

uploadForm.html

	

		

	

	

		

			

				

					
File to upload: