很久以前就想写一篇Spring Mvc上传文件的文章,但是一直都比较忙,趁着今天比较闲,就先为大家介绍一下Spring Mvc提交form表单上传文件。老规矩,coding云还提供在线系统演示,大家可以看着本文,同时对照着演示案例学习。上传文件系统演示
一、首先,我们要准备好form表单,代码示例如下:
<div class="panel-body"> <form id ="firstUpdateForm" action="/demo/upload/firstUpload" method="post" enctype="multipart/form-data" class="form-horizontal" role="form" target="hidden_frame"> <div class="modal-body"> <div class="form-group"> <label class="col-sm-3 control-label">上传文件</label> <div class="col-sm-5"> <input type="file" id="firstDemoImgFile" name="imgFile"> </div> </div> </div> <div class="modal-footer"> <div id="firstUploadSucceed" style="display: none;"> <strong>新增成功!</strong><span id="firstUploadSucceedMsg"></span> </div> <div id="firstUploadFailed" style="display: none;"> <strong>对不起!新增失败</strong><span id="firstUploadFailedMsg"></span> </div> <button id="createPeriadBtn" type="submit" class="btn btn-default">确定 </button> </div> </form> <iframe name='hidden_frame' id="hidden_frame" style='display:none'></iframe> </div>
这里先详细介绍一下该form表单里重要的东西:
- form表单提交的类型一定要加上enctype="multipart/form-data",这是提交媒体文件的声明
- form表单提交的target="hidden_frame",这是为了后台处理完成后返回结果刷新name为hidden_frame的iframe,这样就不会刷新当前页面了,大家可以对照上传文件系统演示,提交成功、失败会打印操作结果信息,就是利用这个实现的,模仿了ajax的方式,ajax是不能提交文件到后台的。
- 为了打印后台返回的结果,这个jsp文件需要引用一个js文件,uploadDemo.js,当controller返回操作结果后,会调用成功、失败的方法,在页面打印出结果,这里请和下面介绍的controller联系起来理解。
二、后台controller接收请求,代码示例如下:
@Controller @RequestMapping("/demo/upload") public class UploadController extends BaseController { @Autowired private UploadDemoService uploadDemoService; /** * 第一种Spring Mvc上传文件,提交form表单文件到一个frame,刷新该frame,页面打印出返回的结果 * @param request * @param demo * @return */ @RequestMapping(value = "firstUpload", method = RequestMethod.POST) @ResponseBody public Object firstUpload(HttpServletRequest request, UploadDemoVo demo){ logger.info("firstUpload info:" + demo.toString()); boolean flag = false; //errorMessage:上传失败,则是错误信息;上传成功,则提示成功以及显示文件上传后的地址 String errorMessage = ""; try{ flag = uploadDemoService.uploadForm(demo); errorMessage += "文件地址:http://demo.codingyun.com/demoFileDirectory/" + demo.getImgFile().getOriginalFilename(); }catch (ServiceException serviceE){ logger.error("firstUpload failed!" , serviceE); errorMessage = serviceE.getMessage(); }catch (Exception e){ logger.error("firstUpload failed!" , e); errorMessage = "新增文件失败!"; } if(flag){ //上传成功,返回到前台,调用uploadSucced()这个方法 return "<script>window.parent.uploadSucced('" + errorMessage + "');</script>"; } //上传失败,返回到前台,调用uploadFailed()这个方法 return "<script>window.parent.uploadFailed('" + errorMessage + "');</script>"; } }
controller接收图片属性的实体类UploadDemoVo,源码如下:
public class UploadDemoVo { /** * 文件 */ private MultipartFile imgFile; public MultipartFile getImgFile() { return imgFile; } public void setImgFile(MultipartFile imgFile) { this.imgFile = imgFile; } @Override public String toString() { return "UploadDemoVo [imgFile=" + imgFile + "]"; } public boolean validateFile() throws ServiceException{ if(!ConstantUtil.fileTypeImg.contains(this.getImgFile().getContentType())){ throw new ServiceException("文件类型只能是jpeg、png!"); } if(this.getImgFile().getSize() > 1000 * 100){ throw new ServiceException("文件最大不能超过100KB!"); } return true; } }
这里的controller我已经将注释写好,大家可以理解一下,若有不明白的可以随时在本页下方留言给我。
三、controller会调用后台service保存图片到服务器UploadDemoService,该service已经注入到controller中,源码如下:
这个是接口
public interface UploadDemoService { /** * 上传文件到指定路径 * destinationDir 目标路径 * 2014年6月10日 */ public boolean uploadFile(String destinationDir, MultipartFile file, String filename) throws Exception; }
这个是接口的实现类
@Service public class UploadDemoServiceImpl implements UploadDemoService { @Override public boolean uploadForm(UploadDemoVo demo) throws Exception { demo.validateFile(); uploadFile( "E:/test", demo.getImgFile(), demo.getImgFile().getOriginalFilename()); return true; } private boolean uploadFile(String destinationDir, MultipartFile file, String filename) throws Exception { logger.info("文件长度: " + file.getSize()); logger.info("文件类型: " + file.getContentType()); logger.info("文件名称: " + file.getName()); logger.info("文件原名: " + file.getOriginalFilename()); logger.info("========================================"); try { SaveFileFromInputStream(file.getInputStream(), destinationDir, filename); } catch (IOException e) { logger.info(e.getMessage()); return false; } return true; } /**保存文件 * @param stream * @param path * @param filename * @throws IOException */ private void SaveFileFromInputStream(InputStream stream,String path,String filename) throws IOException { FileOutputStream outputStream = new FileOutputStream( path + "/"+ filename); int byteCount = 0; byte[] bytes = new byte[1024]; while ((byteCount = stream.read(bytes)) != -1){ outputStream.write(bytes, 0, byteCount); } outputStream.close(); stream.close(); } }
四、测试效果
最后再跟大家说下,对照着上传文件系统演示,再看该文档会更容易理解,也更容易学会。如果大家有什么问题,请在底部留言,我会及时回复。
(转载本站原创文章请注明作者与出处Coding云--codingyun.com)