多图片上传 可预览增加删除，使用js局部刷新，并结合spingmvc使用

1.使用XMLHttpRequest对象发送文件

js代码如下：

var form = new FormData();        var xhr = new XMLHttpRequest();        for (var i = 0, file; file = this.fileFilter[i]; i++) {        form.append("file", file);         }           xhr.open("POST", self.url, true);        xhr.send(form);

使用springmvc的MultipartFile[] files参数接收不到文件，而直接表单提交是可以收到文件的，因此另谋出路，使用servlet进行接收。

2.servlet接收代码如下：

private String uploadPath;    File tempPathFile;            protected void doPost(HttpServletRequest request,              HttpServletResponse response) throws ServletException, IOException {      String fileName="";    String str="";        try {              // Create a factory for disk-based file items                  uploadPath=request.getSession().getServletContext()              .getRealPath("/") + "upload/" ;            DiskFileItemFactory factory = new DiskFileItemFactory();                // Set factory constraints              factory.setSizeThreshold(4096);            factory.setRepository(tempPathFile);              // Create a new file upload handler              ServletFileUpload upload = new ServletFileUpload(factory);                // Set overall request size constraint              upload.setSizeMax(4194304);               List<FileItem> items = upload.parseRequest(request);                     Iterator<FileItem> i = items.iterator();                         while (i.hasNext()) {                  FileItem fi = (FileItem) i.next();                   fileName = fi.getName();                  if (fileName != null) {                      File fullFile = new File(new String(fi.getName().getBytes(), "utf-8"));                     File savedFile = new File(uploadPath, fullFile.getName());                     if (!savedFile.getParentFile().exists())                      savedFile.getParentFile().mkdirs();                      fi.write(savedFile);                      str=str+fullFile.getName()+"*";                }                             }                               } catch (Exception e) {           System.out.print(e);        }                  response.getWriter().write("上传成功!");      } 

3.servlet使用springmvc的注解需要加如下代码：

@Autowired     private TestDao testdao;    public void init(ServletConfig config) throws ServletException {          SpringBeanAutowiringSupport.processInjectionBasedOnServletContext(this,                  config.getServletContext());      } 

4.整体效果图如下