使用Dropzone上传图片及回显演示样例

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一、图片上传所涉及到的问题

1、HTML页面中引入这么一段代码

<div class="row"> <div class="col-md-12"> <form dropzone2 class="dropzone" enctype="multipart/form-data" method="post"></form> </div> </div>

2、在指令中发送POST请求

关键代码例如以下

注意上述URL的请求方式，要在Angular模拟请求中放行。

格式例如以下：

var hubMock = angular.module('hubMock', ['ngMockE2E']); hubMock.run(['$httpBackend', '$http', function ($httpBackend, $http) { $httpBackend.whenGET(/\.html/).passThrough(); $httpBackend.whenGET(/\.json/).passThrough(); $httpBackend.whenPOST(/rest\/components\/.+\/.+\/images/).passThrough(); }]);

$httpBackend.whenPOST(/rest\/components\/.+\/.+\/images/).passThrough(); 放行图片上传发送是POST 请求。

3、处理上传图片的请求将其存储在本地

@POST @Path("/{componentName: \\w+}/{version: \\d\\.\\d\\.\\d}/images") @Produces(MediaType.APPLICATION_JSON) public Response uploadMyComponentImage(@Context HttpServletRequest request, @PathParam("componentName") String componentName, @PathParam("version") String version) { Map<String, String> infoMap = componentService.uploadMyComponentImage(request, componentName, version); return Response.ok(infoMap).build(); }

4、通过接口及事实上现类来处理图片上传的位置

@Override public Map<String, String> uploadMyComponentImage(HttpServletRequest request, String componentName, String version) { Map<String, String> infoMap = new HashMap<String, String>(); String url = null; try { url = application.getStorageLocation(File.separator + componentName + File.separator + version).getAbsolutePath(); } catch (IOException e1) { e1.printStackTrace(); } DiskFileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); try { Map<String, List<FileItem>> items = upload.parseParameterMap(request); for (Entry<String, List<FileItem>> entry : items.entrySet()) { String key = entry.getKey(); Iterator<FileItem> itr = items.get(key).iterator(); while (itr.hasNext()) { FileItem item = itr.next(); String newfileName = UUID.randomUUID().toString() + "-" + item.getName(); infoMap.put("newfile", "" + newfileName); File file = new File(url); if (!file.exists()) { file.mkdirs(); } file = new File(url + File.separator + "img" + File.separator + newfileName); item.write(file); } } } catch (FileUploadException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } return infoMap; }

在这里返回的是一个map, key是newfile,value是”” + newfileName，因此在上传成功后就能够取得图片的信息。例如以下演示样例 imageInfo.newfile;：

this.on("success", function(file,imageInfo) { file._viewLink.href = imageInfo.newfile; file._viewLink.name = imageInfo.newfile; $scope.$apply(function() { $scope.component.image="rest/components/"+$scope.component.name+"/"+$scope.component.version+"/"+imageInfo.newfile; }); });

二、页面中的图片怎样进行回显？

1、现今的站点上图片上的获取方式主要是以Get请求的方式传回图片流到浏览器端，这里相同採用请求主动获取图片的方式。

页面回显时会主动发送请求：

“rest/components/”+scope.component.name+"/"+scope.component.version +”/”+$scope.component.image

真实请求路径是这种：

localhost:8080/xxxxxx/rest/components/2_component1/1.0.0/0c6684ad-84df-4e0e-8163-9e2d179814e6-Penguins.jpg

2、后台怎样接受请求，处理请求呢？

參见下面代码，返回到浏览器的实际上就是一个输出流。

关键代码演示样例

/** * get pictures OutputStream * * @param componentName * @param version * @return */ @GET @Path("/{componentName: \\w+}/{version: \\d\\.\\d\\.\\d}/{imagePath: .+}") @Produces(MediaType.APPLICATION_OCTET_STREAM) public Response findImages(@PathParam("componentName") final String componentName, @PathParam("version") final String version, @PathParam("imagePath") final String imagePath) { StreamingOutput output = new StreamingOutput() { private BufferedInputStream bfis = null; public void write(OutputStream output) throws IOException, WebApplicationException { try { String filePath = ""; //推断图片的请求路径是否长路径，这个依据需求而来的 if (imagePath.contains("/")) { //取出图片 filePath = application.getStorageLocation(File.separator + componentName + File.separator + version) + File.separator + "img" + File.separator + imagePath.split("/")[imagePath.split("/").length - 1]; } else { //取出图片 filePath = application.getStorageLocation(File.separator + componentName + File.separator + version) + File.separator + "img" + File.separator + imagePath; } bfis = new BufferedInputStream(new FileInputStream(filePath)); int read = 0; byte[] bytes = new byte[1024]; while ((read = bfis.read(bytes)) != -1) { output.write(bytes, 0, read); } } catch (Exception e) { e.printStackTrace(); } finally { try { if (bfis != null) { bfis.close(); } output.flush(); output.close(); } catch (Exception e2) { e2.printStackTrace(); } } } }; //返回给浏览器 return Response.ok(output, MediaType.APPLICATION_OCTET_STREAM).build(); }