Springboot Http文件的访问 Url 转换 MultipartFile ，File 转 MultipartFile

梦里梦外; 2023-09-28 21:57 169阅读 0赞

pom.xml

<dependency>
                <groupId>commons-fileupload</groupId>
                <artifactId>commons-fileupload</artifactId>
                <version>1.2.2</version>
            </dependency>

MyFileConvertUtil.java

/**
     * @Author: JCccc
     * @Date: 2022-8-25 02:15
     * @Description:
     */
    public class MyFileConvertUtil {
    
        protected static final Logger logger = LoggerFactory.getLogger(MyFileConvertUtil.class);
    
        /**
         * Url 转换 MultipartFile
         * @param url
         * @param fileName
         * @return
         * @throws Exception
         */
        public static MultipartFile urlToMultipartFile(String url, String fileName) throws Exception {
            logger.info("开始 url 转换 MultipartFile，url={} ,fileName={}",url,fileName);
            File file = null;
            MultipartFile multipartFile = null;
            try {
                HttpURLConnection httpUrl = (HttpURLConnection) new URL(url).openConnection();
                httpUrl.connect();
                logger.info("成功建立httpUrl连接"+httpUrl.toString());
                file = inputStreamToFile(httpUrl.getInputStream(),fileName);
                multipartFile = fileToMultipartFile(file);
                httpUrl.disconnect();
            } catch (Exception e) {
                e.printStackTrace();
            }
            logger.info("完成 url 转换 MultipartFile，url={} ,fileName={}",url,fileName);
            return multipartFile;
        }
    
    
        /**
         * InputStream 转 File
         * @param ins
         * @param fileName
         * @return
         * @throws Exception
         */
        public static File inputStreamToFile(InputStream ins, String fileName) throws Exception{
            logger.info("开始 InputStream 转换 File,fileName={}",fileName);
            File file = new File(System.getProperty("java.io.tmpdir") + File.separator + fileName);
            OutputStream os = new FileOutputStream(file);
            int bytesRead;
            int len = 8192;
            byte[] buffer = new byte[len];
            while ((bytesRead = ins.read(buffer, 0, len)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
            os.close();
            ins.close();
            logger.info("完成 InputStream 转换 File,fileName={}",fileName);
            return file;
        }
    
    
        /**
         * File 转 MultipartFile
         * @param file
         * @return
         */
        public static CommonsMultipartFile fileToMultipartFile(File file) {
            logger.info("fileToMultipartFile文件转换中："+file.getAbsolutePath());
            FileItemFactory factory = new DiskFileItemFactory(16, null);
            FileItem item=factory.createItem(file.getName(),"text/plain",true,file.getName());
            int bytesRead = 0;
            byte[] buffer = new byte[8192];
            try {
                FileInputStream fis = new FileInputStream(file);
                OutputStream os = item.getOutputStream();
                while ((bytesRead = fis.read(buffer, 0, 8192)) != -1) {
                    os.write(buffer, 0, bytesRead);
                }
                os.close();
                fis.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return new CommonsMultipartFile(item);
        }
    
    }

使用简例：

@RequestMapping("/test")
        public void test(@RequestParam String fileUrl)  {
            try {
                File fileAuth = new File(fileUrl);
                //原文件名
                String sourceName = fileAuth.getName();
                //自己起文件名
                String newFileName="JCccc学Java文件名.xlsx";
    
                MultipartFile file = MyFileConvertUtil.urlToMultipartFile(fileUrl, newFileName);
    
            } catch (Exception e) {
                e.printStackTrace();
            }
        }