看来我的情况很简单，所以我猜这个问题很愚蠢。尽管如此......我没有看到它。
我正在尝试接受文件集合的上传，并一直在查看这篇文章作为指南：
http://viralpatel.net/blogs/spring-mvc-multiple-file-upload-example/
这是表单上传客户端：
<form:form method="post" action="save.html" modelAttribute="uploadArtifact" enctype="multipart/form-data">
<div class="controls" id="artifacts">
<input type="file" id="uploader" class="multi"/>
</div>
<div>
<input type="submit" value="Upload" />
</div>
</form:form>
这是模型/ Bean 代码：
public class ArtifactModel {
private List<MultipartFile> artifacts;
public List<MultipartFile> getArtifacts() {
return artifacts;
}
public void setArtifacts(List<MultipartFile> artifacts) {
this.artifacts = artifacts;
}
}
...和控制器代码：
@Controller
public class ArtifactController {
private static Log logger = LogFactory.getLog(ArtifactController.class);
// @Autowired
// ArtifactService artifactService;
@RequestMapping(value = "/getUploadDialog", method = RequestMethod.GET)
public String displayForm() {
return "uploadArtifacts";
}
@RequestMapping(value = "/save", method = RequestMethod.POST)
public void save(
@ModelAttribute("uploadArtifact") ArtifactModel uploadArtifact,
Model map) {
logger.info("Received file upload request with "+uploadArtifact.getArtifacts().size()+" files");
List<MultipartFile> files = uploadArtifact.getArtifacts();
List<String> fileNames = new ArrayList<String>();
if (null != files && files.size() > 0) {
for (MultipartFile multipartFile : files) {
String fileName = multipartFile.getOriginalFilename();
fileNames.add(fileName);
// Handle file content - multipartFile.getInputStream()
logger.info("Received file with filename: " + fileName);
}
}
map.addAttribute("files", fileNames);
}
}
当我尝试调用应该来自 uploadArtifact @ModelAttribute 参数的 ArtifactModel 对象上的 getter 时，我得到了 NullPointerException ...
我查看了浏览器调试器，发现客户端正在发送数据......
建议？