Spring portlet表单：@ModelAttribute未填充

Question

我是Spring的初学者，我想知道为什么我的ModelAttribute没有填充（所有值都为null）

我想创建一个multipart，允许我上传一个csv文件以及CSV文件的类型。

我的代码是这样的：

在CSVUpload-portlet.xml中：

<bean class="org.springframework.web.portlet.mvc.annotation.DefaultAnnotationHandlerMapping"/>
<bean class="org.springframework.web.portlet.mvc.annotation.AnnotationMethodHandlerAdapter">

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <property name="maxUploadSize" value="100000000"></property>
</bean>

<bean id="viewResolver"
    class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="viewClass"
        value="org.springframework.web.servlet.view.JstlView" />
    <property name="prefix" value="/WEB-INF/jsp/" />
    <property name="suffix" value=".jsp" />
</bean>

CSVUploadPortlet.java（控制器）

*All imports 

@Controller("uploadCsvToDatabase")
@RequestMapping(value = "VIEW")
public class CSVUploadPortlet {
  private static final Logger log = Logger.getLogger(CSVUploadPortlet.class);
  private static IWBCSVUploadRemote csvupload;

  @RenderMapping
  public String viewCSVUploadBase(Model model, RenderRequest request) {
    try {

    } catch (Exception e) {
      e.printStackTrace();

      log.info("problem in retrieving the CSV Upload service" + e);
    }
    return "csvupload/csvupload_view";
  }

  @ModelAttribute("csvFileUploadVO")
  public CSVFileUploadVO getCommandObject() 
  {
    System.out.println("SpringFileController -> getCommandObject -> Building VO");
    return new CSVFileUploadVO();
  }

  @ActionMapping(params="action=uploadCsvToDatabase")
  public void uploadCsvToDatabase(
      @ModelAttribute("csvFileUploadVO") CSVFileUploadVO csvFileUploadVO, BindingResult result, ActionRequest request, ActionResponse response, SessionStatus sessionStatus){
    try{
      System.out.println("FileType:"+csvFileUploadVO.getFileType()); //This returns null
      System.out.println("CSVFile Size:"+csvFileUploadVO.getCsvFile().getSize());  //This returns a null-pointer exception
    } catch (Exception e) {
      log.info("Problem in retrieving the CSVUpload configuration list " + e);
      e.printStackTrace();
    }
  }
}

CSV file upload VO.Java

import org.springframework.web.multipart.commons.CommonsMultipartFile;

public class CSVFileUploadVO {
  private String fileType;
  private CommonsMultipartFile csvFile;
  private String message;

  public CSVFileUploadVO() {
  }

  public String getFileType() {
    return fileType;
  }

  public void setFileType(String fileType) {
    this.fileType = fileType;
  }

  public String getMessage() {
          return message;
  }

  public void setMessage(String message) {
          this.message = message;
  }

  public CommonsMultipartFile getCsvFile() {
          return csvFile;
  }

  public void setCsvFile(CommonsMultipartFile csvFile) {
          this.csvFile = csvFile;
  }
}

表单JSP

All taglibs imported...
<portlet:actionURL var="fileUploadURL">
    <portlet:param name="action" value="uploadCsvToDatabase" />
</portlet:actionURL>

<form:form method="post" action="${fileUploadURL}"
    commandName="csvFileUploadVO" enctype="multipart/form-data">
    <table>
        <tbody>
            <tr>
                <td><label>Department:</label></td>
                <td><form:select path="fileType">
                        <form:option value="BRMAdd" label="BRM Add" />
                        <form:option value="FOSAdmin" label="FOS Admin" />
                        <form:option value="FOSRM" label="FOS RM" />
                        <form:option value="FOSTeam" label="FOS Team" />
                        <form:option value="ITRelationships" label="IT Relationships" />
                        <form:option value="HRAttendance" label="HR Attendance" />
                        <form:option value="iCareCallReport" label="iCare Call Report" />
                    </form:select></td>
            </tr>
            <tr>
                <td><label>Specify your File:</label></td>
                <td><form:input path="csvFile" type="file" /></td>
            </tr>
            <tr>
            <tr>
                <td colspan="100%"><input type="submit" value="Submit" /></td>
            </tr>
            <tr>
                <td colspan="100%">${csvFileUploadVO.message}</td>
            </tr>
        </tbody>
    </table>
</form:form>

我知道这似乎要求你帮我解决问题，但我已经坚持了8个小时，阅读每个资源和stackoverflow网站，我可以google。但尽管如此，我还是找不到任何东西。

谢谢你的帮助。

Answer 1

你会想看看http://static.springsource.org/spring/docs/3.0.x/reference/mvc.html#mvc-multipart-resolver特别是RequestMapping参数是MultipartFile

@RequestMapping(value = "/form", method = RequestMethod.POST)
  public String handleFormUpload(@RequestParam("name") String name,
    @RequestParam("file") MultipartFile file) {

Answer 2

您必须在JSP表单中定义ModelAttribute，如下所示：

<form:form method="post" action="${fileUploadURL}"
modelAttribute="csvFileUploadVO" enctype="multipart/form-data">

Answer 3

Liferay 6.0.5和Spring 3.2.2.RELEASE：

我试过编辑spring类，但是这个问题有更简单的解决方案。只需检查您的CommonsPortletMultipartResolver是否真的已经启动。它在spring.xml中声明的事实并不意味着它已被加载。

如果未初始化，则请求的文件部分永远不会转换为CommonsMultipartFile，因为您的请求不会是公共Multipart请求。

CommonsPortletMultipartResolver将由org.springframework.web.portlet.DispatcherPortlet生命周期调用，如果它已加载并且spring使用此类。

Answer 4

你的多部分解析器必须具有id portletMultipartResolver并且类型为org.springframework.web.portlet.multipart.CommonsPortletMultipartResolver

<bean id="portletMultipartResolver" class="org.springframework.web.portlet.multipart.CommonsPortletMultipartResolver">
</bean>