springboot实现文件上传下载功能

朱雀 2023-07-09 02:14 190阅读 0赞

# SpringBoot实现文件上传下载功能 #

### 开发环境 ###

- SpringBoot 2.2.1.RELEASE
    - web依赖
       <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

### 配置参数介绍 ###

#启用文件上传，默认为true
    - spring.servlet.multipart.enabled=true
    #文件大于该阈值时，将写入磁盘（KB/MB）
    - spring.servlet.multipart.file-size-threshold=0KB
    #单个文件最大值（KB/MB）
    - spring.servlet.multipart.max-file-size=10MB
    #单个请求多个文件的最大值（KB/MB）
    - spring.servlet.multipart.max-request-size=10MB

## 文件上传 ##

#### 前端（单个文件上传） ####

- pom文件导入tymeleaf
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
    - 配置tymeleaf
    	spring.thymeleaf.model=HTML
    	spring.thymeleaf.encoding=UTF-8
    	spring.thymeleaf.cache=false

*  文件上传

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>thymeleaf test</title>
    </head>
    <body>
        <form method="post" enctype="multipart/form-data"
              action="/upload" target="uploadFrame">
            <input type="file" name="file"/>
            <input type="submit" name="Submit" value="上传"/>
        </form>
    </body>
    </html>

#### 后端接口以及功能实现（单个文件上传） ####

*  Controller接口

@Autowired
        private FileManageService fileManageService;
    
        @PostMapping("/upload")
        @ResponseBody
        public String fileUpload(@RequestParam("file") MultipartFile file){ 
            if (Objects.isNull(file)){ 
                return "文件上传失败，请重新选择文件";
            }
            return fileManageService.upload(file);
        }

*  service实现

private static final Logger LOGGER = LoggerFactory.getLogger(FileManageService.class);
    
        @Value("${file_hostpath}")
        private String fileHostPath;
    
        @Override
        public String upload(MultipartFile file) { 
            File test = new File(fileHostPath+file.getOriginalFilename());
            if (!test.exists()){ 
                test.mkdirs();
            }
            try { 
                file.transferTo(test);
            }catch (IOException e){ 
                LOGGER.error(file.getOriginalFilename()+"文件上传失败", e);
            }
            return "文件上传成功";
        }

## 文件下载 ##

*  Controller接口

@GetMapping("/download")
        @ResponseBody
        public String fileDownload(@RequestParam("fileName") String fileName, HttpServletResponse response){ 
            if (Objects.isNull(fileName)){ 
                return "文件下载失败，请选择文件要下载的文件";
            }
            return fileManageService.download(fileName, response);
        }

*  service实现

public String download(String fileName, HttpServletResponse response){ 
            File file = new File(fileHostPath + fileName);
            if (!file.exists()){ 
                return "文件不存在";
            }
            byte[] bytes = new byte[SIZE];
            BufferedInputStream bufferedInputStream = null;
            OutputStream outputStream = null;
            FileInputStream fileInputStream = null;
            try { 
                fileInputStream = new FileInputStream(file);
                bufferedInputStream = new BufferedInputStream(fileInputStream);
    
                response.setContentType(MediaType.APPLICATION_OCTET_STREAM.toString());
                response.addHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "UTF-8"));
                outputStream = response.getOutputStream();
                int length;
                while ((length = bufferedInputStream.read(bytes)) != -1){ 
                    outputStream.write(bytes, 0, length);
                }
                outputStream.flush();
            }catch (Exception e){ 
                LOGGER.error("文件下载失败", e);
            }finally { 
                try { 
                    if (bufferedInputStream != null){ 
                        bufferedInputStream.close();
                    }
    
                    if (outputStream != null){ 
                        outputStream.close();
                    }
    
                    if (fileInputStream != null){ 
                        fileInputStream.close();
                    }
                }catch (IOException e){ 
                    LOGGER.error(e.getMessage(), e);
                }
            }
            return "success";
        }