SpringBoot集成文件 - 基础的文件上传和下载

以你之姓@ 2024-02-18 13:58 57阅读 0赞

#### Pom依赖 ####

引入spring-boot-starter-web即可

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

#### 文件上传 ####

上传一个文件，并保存到本地文件夹中

@PostMapping("/upload")
    public ResponseResult<String> upload(@RequestParam(value = "file", required = true) MultipartFile file) {
        try {
            // 本地文件保存位置
            String uploadPath = "/Users/pdai/uploadFile"; // 改这里
            File uploadDir = new File(uploadPath);
            if (!uploadDir.exists()) {
                uploadDir.mkdir();
            }
            log.info(uploadDir.getAbsolutePath());
    
            // 本地文件
            File localFile = new File(uploadPath + File.separator + file.getOriginalFilename());
    
            // transfer to local
            file.transferTo(localFile);
        } catch (Exception e) {
            e.printStackTrace();
            return ResponseResult.fail(e.getMessage());
        }
        return ResponseResult.success();
    }

#### postman模拟上传的请求 ####

#### ![34689535536347a688be56368ed59452.png][] ####

#### 文件下载 ####

从本地文件夹中读取文件，并通过http下载

@GetMapping("/download")
    public void download(HttpServletResponse response) {
        response.reset();
        response.setContentType("application/octet-stream");
        response.setHeader("Content-disposition",
                "attachment;filename=file_" + System.currentTimeMillis() + ".hprof");
    
        // 从文件读到servlet response输出流中
        File file = new File("/Users/pdai/pdai_heap_dump_test.hprof"); // 改这里
        try (FileInputStream inputStream = new FileInputStream(file);) { // try-with-resources
            byte[] b = new byte[1024];
            int len;
            while ((len = inputStream.read(b)) > 0) {
                response.getOutputStream().write(b, 0, len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

![6896256d7dac41cea8ec118ea1638342.png][]

注：

如果使用postman下载文件，默认的response大小是50MB，下载大于50MB的文件需要在这里自行设置。

![780c77307f194375bff184289745ca8c.png][]

**SpringBoot文件上传大小参数？**

SpringBoot对上传的文件大小有限制，默认的最大每个文件配置最大为1MB，默认多个文件上传（上传目标文件夹）总大小是10MB。

spring:
      servlet:
        multipart:
          max-file-size: 1024MB # 单个文件大小
          max-request-size: 10240MB # 总文件大小（允许存储文件的文件夹大小）

更多其它的参数可以参看MultipartProperties类

@ConfigurationProperties(prefix = "spring.servlet.multipart", ignoreUnknownFields = false)
    public class MultipartProperties {
    
    	/**
    	 * Whether to enable support of multipart uploads.
    	 */
    	private boolean enabled = true;
    
    	/**
    	 * Intermediate location of uploaded files.
    	 */
    	private String location;
    
    	/**
    	 * Max file size.
    	 */
    	private DataSize maxFileSize = DataSize.ofMegabytes(1);
    
    	/**
    	 * Max request size.
    	 */
    	private DataSize maxRequestSize = DataSize.ofMegabytes(10);
    
    	/**
    	 * Threshold after which files are written to disk.
    	 */
    	private DataSize fileSizeThreshold = DataSize.ofBytes(0);
    
    	/**
    	 * Whether to resolve the multipart request lazily at the time of file or parameter
    	 * access.
    	 */
    	private boolean resolveLazily = false;
    
    }

多个文件上传？

Spring支持接收多个文件的，只需要用MultipartFile接收即可

@PostMapping("/upload")
    public ResponseResult<String> upload(MultipartFile[] files) {
    
    }

[34689535536347a688be56368ed59452.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/02/18/26589cae41634b5a98fdc661d3fbd7c0.png
[6896256d7dac41cea8ec118ea1638342.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/02/18/b55f5d6e4b954acbac539dc927ee3dce.png
[780c77307f194375bff184289745ca8c.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/02/18/501ca272c375404c9ae96ef87962da50.png