springmvc文件上传,使用它的MultipartHttpServletRequest,tomcat中正常,resion中报错
http://www.oschina.net/question/699032_75001
http://zhupan.iteye.com/blog/26427
实现图片上传
用户必须能够上传图片,因此需要文件上传的功能。比较常见的文件上传组件有Commons FileUpload(http://jakarta.apache.org/commons/fileupload/a>)和COS FileUpload(http://www.servlets.com/cos),Spring已经完全集成了这两种组件,这里我们选择Commons FileUpload。
由于Post一个包含文件上传的Form会以multipart/form-data请求发送给服务器,必须明确告诉DispatcherServlet如何处理MultipartRequest。首先在dispatcher-servlet.xml中声明一个MultipartResolver:
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> <!-- 设置上传文件的最大尺寸为1MB --> <property name="maxUploadSize"> <value>1048576</value> </property> </bean>
这样一旦某个Request是一个MultipartRequest,它就会首先被MultipartResolver处理,然后再转发相应的Controller。
在UploadImageController中,将HttpServletRequest转型为MultipartHttpServletRequest,就能非常方便地得到文件名和文件内容:
public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception { // 转型为MultipartHttpRequest: MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request; // 获得文件: MultipartFile file = multipartRequest.getFile(" file "); // 获得文件名: String filename = file.getOriginalFilename(); // 获得输入流: InputStream input = file.getInputStream(); // 写入文件 // 或者: File source = new File(localfileName.toString()); multipartFile.transferTo(source); }
生成缩略图 (目录)
当用户上传了图片后,必须生成缩略图以便用户能快速浏览。我们不需借助第三方软件,JDK标准库就包含了图像处理的API。我们把一张图片按比例缩放到120X120大小,以下是关键代码:
public static void createPreviewImage(String srcFile, String destFile) { try { File fi = new File(srcFile); // src File fo = new File(destFile); // dest BufferedImage bis = ImageIO.read(fi); int w = bis.getWidth(); int h = bis.getHeight(); double scale = (double) w / h; int nw = IMAGE_SIZE; // final int IMAGE_SIZE = 120; int nh = (nw * h) / w; if (nh > IMAGE_SIZE) { nh = IMAGE_SIZE; nw = (nh * w) / h; } double sx = (double) nw / w; double sy = (double) nh / h; transform.setToScale(sx, sy); AffineTransformOp ato = new AffineTransformOp(transform, null); BufferedImage bid = new BufferedImage(nw, nh, BufferedImage.TYPE_3BYTE_BGR); ato.filter(bis, bid); ImageIO.write(bid, " jpeg ", fo); } catch (Exception e) { e.printStackTrace(); throw new RuntimeException( " Failed in create preview image. Error: " + e.getMessage()); } }