springboot:upload

FileUploadConfiguration.java
===================================================
@Configuration
public class FileUploadConfiguration {

    @Bean
    public MultipartConfigElement multipartConfigElement() {
        MultipartConfigFactory factory = new MultipartConfigFactory();
        // 设置文件大小限制 ,超出设置页面会抛出异常信息，
        // 这样在文件上传的地方就需要进行异常信息的处理了;
        factory.setMaxFileSize("256KB"); // KB,MB
        /// 设置总上传数据总大小
        factory.setMaxRequestSize("512KB");
        // Sets the directory location where files will be stored.
        // factory.setLocation("路径地址");
        return factory.createMultipartConfig();
    }

}
===================================================
Controller.java
===================================================
    /**
     * 文件上传具体实现方法（单文件上传）
     *
     * @param file
     * @return <form method="POST" enctype="multipart/form-data" action="/upload">
     * <p>
     * 文件：<input type="file" name="file" />
     * </p>
     * <p>
     * <input type="submit" value="上传" />
     * </p>
     * </form>
     */
    @RequestMapping(value = "/upload", method = RequestMethod.POST)
    @ResponseBody
    public String upload(@RequestParam("file") MultipartFile file) {
        if (!file.isEmpty()) {
            try {
                // 这里只是简单例子，文件直接输出到项目路径下。
                // 实际项目中，文件需要输出到指定位置，需要在增加代码处理。
                // 还有关于文件格式限制、文件大小限制，详见：中配置。
                BufferedOutputStream out = new BufferedOutputStream(
                        new FileOutputStream(new File(file.getOriginalFilename())));
                out.write(file.getBytes());
                out.flush();
                out.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
                return "上传失败," + e.getMessage();
            } catch (IOException e) {
                e.printStackTrace();
                return "上传失败," + e.getMessage();
            }
            return "上传成功";
        } else {
            return "上传失败，因为文件是空的.";
        }
    }

    /**
     * 多文件上传 主要是使用了MultipartHttpServletRequest和MultipartFile
     *
     * @param request
     * @return <form method="POST" enctype="multipart/form-data"
     * action="/upload/batch">
     * <p>
     * 文件1：<input type="file" name="file" />
     * </p>
     * <p>
     * 文件2：<input type="file" name="file" />
     * </p>
     * <p>
     * 文件3：<input type="file" name="file" />
     * </p>
     * <p>
     * <input type="submit" value="上传" />
     * </p>
     * </form>
     */
    @RequestMapping(value = "/upload/batch", method = RequestMethod.POST)
    public
    @ResponseBody
    String batchUpload(HttpServletRequest request) {
        List<MultipartFile> files = ((MultipartHttpServletRequest) request).getFiles("file");
        MultipartFile file = null;
        BufferedOutputStream stream = null;
        for (int i = 0; i < files.size(); ++i) {
            file = files.get(i);
            if (!file.isEmpty()) {
                try {
                    byte[] bytes = file.getBytes();
                    stream = new BufferedOutputStream(new FileOutputStream(new File(file.getOriginalFilename())));
                    stream.write(bytes);
                    stream.close();
                } catch (Exception e) {
                    stream = null;
                    return "You failed to upload " + i + " => " + e.getMessage();
                }
            } else {
                return "You failed to upload " + i + " because the file was empty.";
            }
        }
        return "upload successful";
    }