Struts2 Fileupload在动作类中给出空文件 [英] Struts2 Fileupload giving null file in the action class

问题描述

我试图在我的web应用程序中使用struts2 fileUpload拦截器来实现文件上传过程。下面是我在
$ b

index.jsp中的代码

 < tags：form action =fileUploadmethod =postenctype =multipart / form-data> 
< tags：file name =fileUploadlabel =选择文件/> 
< tags：submit value =上传/> 
< / tags：form> 
  

struts.xml

 < action name =fileUploadclass =com.hibernate.action.FileUploadAction> 
< interceptor-ref name =fileUploadStack/> 
< interceptor-ref name =fileUpload> 
< param name =maximumSize> 1024000< / param> 
< param name =allowedTypes> application / pdf< / param> 
< / interceptor-ref> 
< result name =success> /viewChapters.jsp< / result> 
< / action> 
  

FileUploadAction.java

  public class FileUploadAction extends ActionSupport 
 {
 private file fileUpload; 
 private String contentType; 
 private String fileName; 
 private String destPath; 
 /// setter和getter方法
 public String execute（）
 {
 destPath =C：\\WebPortal_testing; 
尝试
 {
 System.out.println（Source File Name：+ fileUpload）; 
 System.out.println（Destination File Name：+ fileName）; 
 
文件destFile =新文件（destPath，fileName）; 
 FileUtils.copyFile（fileUpload，destFile）; 
 
 catch（IOException异常）
 {
 exception.printStackTrace（）; 
返回错误; 
} 
返回SUCCESS; 
 
  

当我在index.jsp页面选择一个pdf文件并点击上传按钮，它将赋予操作类的fileUpload字段空值。

我正在以调试模式执行应用程序，并给了这个

  System.out.println（Source File Name：+ fileUpload）; 
  

检查它正在返回的内容，

解决方案

拦截器配置错误

FileUploadStack 是：


$ b

 < ;！ - 示例文件上传堆栈 - > 
< interceptor-stack name =fileUploadStack> 
< interceptor-ref name =fileUpload/> 
< interceptor-ref name =basicStack/> 
< / interceptor-stack> 
  

那么你真正定义的是：

< interceptor-ref name =fileUpload/>
< interceptor-ref name =basicStack/>
< interceptor-ref name =fileUpload>
< param name =maximumSize> 1024000< / param>
< param name =allowedTypes> application / pdf< / param>
< / interceptor-ref>使用

• 两次fileUpload拦截器


• 对maximumSize和allowedTypes的限制只能在第二个上使用。
  

$ b

< interceptor-ref name =fileUploadStack>
< param name =fileUpload.maximumSize> 1024000< / param>
< param name =fileUpload.allowedTypes> application / pdf< / param>
< / interceptor-ref>


---

2。文件属性是错误的

内容类型和文件名属性必须以File属性名称开始。

在你的情况下：
$ b

  private file fileUpload; 
 private String fileUploadContentType; 
 private String fileUploadFileName; 
  

您可以在这个问题。

---

你正在打印的文件，而不是文件名

$ b

System.out.println（ 源文件名：+ fileUpload）;


这是文件，而不是文件名，并且btw文件名在另一个变量中传递。 / p>

---

修复此问题并重试。还要注意，当整个世界正在使用< s：<标记：时，使用< 。这样做没有任何好处，只有复杂性。只要使用< s：。

I am trying to implement the file upload process in my web application using struts2 fileUpload interceptor. below is my code in

index.jsp

<tags:form action="fileUpload" method="post" enctype="multipart/form-data">
   <tags:file name="fileUpload" label="Choose File"/>
   <tags:submit value="Upload"/>     
</tags:form> 

struts.xml

<action name="fileUpload" class="com.hibernate.action.FileUploadAction">
    <interceptor-ref name="fileUploadStack"/>
    <interceptor-ref name="fileUpload">
        <param name="maximumSize">1024000</param>
        <param name="allowedTypes">application/pdf</param>
    </interceptor-ref>
    <result name="success">/viewChapters.jsp</result>
</action>

FileUploadAction.java

public class FileUploadAction extends ActionSupport
{
private File fileUpload;
private String contentType;
private String fileName;
private String destPath;
/// setter and getter methods
 public String execute()
{
    destPath="C:\\WebPortal_testing";
    try
    {
        System.out.println("Source File Name:"+fileUpload);
        System.out.println("Destination File Name:"+fileName);

        File destFile= new File(destPath,fileName);
        FileUtils.copyFile(fileUpload, destFile);
    }
    catch(IOException exception)
    {
        exception.printStackTrace();
        return ERROR;
    }
    return SUCCESS;
 }

when I select a pdf file in the index.jsp page and click on upload button it is giving null value to the fileUpload field of the action class.

I am executing the application in debug mode and gave this

System.out.println("Source File Name:"+fileUpload);

to check what it is returning and I am getting null.

解决方案

1. Interceptor configuration is wrong

FileUploadStack is:

<!-- Sample file upload stack -->
<interceptor-stack name="fileUploadStack">
    <interceptor-ref name="fileUpload"/>
    <interceptor-ref name="basicStack"/>
</interceptor-stack>

then what you're really defining is:

    <interceptor-ref name="fileUpload"/>
    <interceptor-ref name="basicStack"/>
    <interceptor-ref name="fileUpload">
        <param name="maximumSize">1024000</param>
        <param name="allowedTypes">application/pdf</param>
    </interceptor-ref>

Using

• two times the fileUpload interceptor
• applying your limitations on maximumSize and allowedTypes only to the second.

Just do

<interceptor-ref name="fileUploadStack">
    <param name="fileUpload.maximumSize">1024000</param>
    <param name="fileUpload.allowedTypes">application/pdf</param>
</interceptor-ref>

---

2. File attributes are wrong

Content type and file name attributes must start with the File attribute name.

In your case:

private File fileUpload;
private String fileUploadContentType;
private String fileUploadFileName;

You can find a full example on this question.

---

3. You are printing the File instead of the filename

System.out.println("Source File Name:"+fileUpload);

That is the file, not the filename, and btw the filename is passed in the other variable.

---

Fix this and retry. Also note that is not safe to use <tags: as prefix when the whole world is using <s:. There's no gain in doing that, only complications. Just use <s:.

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