struts file uploading problem

[lynn fann]

im having problem with the file uploading codes. Im using struts and hibernate and mysql. the errors and code is pasted below. please advice. thanks

Error Message:
java.lang.IllegalArgumentException: Cannot invoke com.strutsexample.form.ContentForm.setFile - argument type mismatch
org.apache.commons.beanutils.PropertyUtilsBean.invokeMethod(PropertyUtilsBean.java:1778)
org.apache.commons.beanutils.PropertyUtilsBean.setSimpleProperty(PropertyUtilsBean.java:1759)
org.apache.commons.beanutils.PropertyUtilsBean.setNestedProperty(PropertyUtilsBean.java:1648)
org.apache.commons.beanutils.PropertyUtilsBean.setProperty(PropertyUtilsBean.java:1677)
org.apache.commons.beanutils.BeanUtilsBean.setProperty(BeanUtilsBean.java:1022)
org.apache.commons.beanutils.BeanUtilsBean.populate(BeanUtilsBean.java:811)
org.apache.commons.beanutils.BeanUtils.populate(BeanUtils.java:298)
org.apache.struts.util.RequestUtils.populate(RequestUtils.java:451)
org.apache.struts.chain.commands.servlet.PopulateActionForm.populate(PopulateActionForm.java:45)
org.apache.struts.chain.commands.AbstractPopulateActionForm.execute(AbstractPopulateActionForm.java:57)
org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:48)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:280)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1858)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:446)
javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:368)



action class code:
ContentForm cfrm = (ContentForm) form;
HibernateSessionFactory.getSessionFactory().getCurrentSession().beginTransaction();
Content content=new Content();
content.setFile(Hibernate.createBlob(cfrm.getFile().getInputStream()));
HibernateSessionFactory.getSessionFactory().getCurrentSession().save(content);


formbean code:
private FormFile file;
public FormFile getFile() {
return file;
}

public void setFile(FormFile file) {
this.file = file;
}


object class:
private Blob file;

public Blob getFile() {
return file;
}

public void setFile(Blob file) {
this.file = file;
}

[Merrill Higginson]

It's hard to tell, but it looks like you've created a custom class named FormFile, and the code for that object is displayed above under the heading "object class". Is that right?

If so, this is what is causing the problem. When doing a file upload, the ActionForm property associated with the file to be uploaded must be of type org.apache.struts.upload.FormFile. It can't be a custom class.

Struts will populate this object for you when the form is submitted. In your Action class, you can then use the FormFile's getInputStream() method to get an input stream for the file being uploaded. Once you have the input stream, you can then use it to write to another object such as a file or a Blob.

This link shows an example of both a file upload to a Blob and a file download from a Blob.

[lynn fann]

I need to set the inputstream to an object. what datatype should i declare?
i have declare the file as

private byte[] file;

but i got the following error:
setFile(byte[]) in com.strutsexample.model.Content cannot be applied to (java.io.InputStream)

[Merrill Higginson]

The file property of your Content bean should be of type java.sql.Blob, and you should use the original code that you showed us to populate it:

content.setFile(Hibernate.createBlob(cfrm.getFile().getInputStream()));

[lynn fann]

im having the following error using the codings displayed below:
java.lang.NullPointerException
com.strutsexample.action.ContentAction.insert(ContentAction.java:51)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:585)


This is my object class

   
package com.strutsexample.model;
 
import java.io.Serializable;
import java.sql.Blob;
 

public class Content implements Serializable {
    private int id;
    private String title;
    private String content;
    private String name;
    private String filename;
    private Blob file;
   
    /** Creates a new instance of Content */
    public Content() {
    }
 
    public String getTitle() {
        return title;
    }
 
    public void setTitle(String title) {
        this.title = title;
    }
    
    public String getContent() {
        return content;
    }
 
    public void setContent(String content) {
        this.content = content;
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
 
 
    public int getId() {
        return id;
    }
 
    public void setId(int id) {
        this.id = id;
    }
 

    public String getFilename() {
        return filename;
    }
 
    public void setFilename(String filename) {
        this.filename = filename;
    }
 
    public Blob getFile() {
        return file;
    }
 
    public void setFile(Blob file) {
        this.file = file;
    }
} 

this is my formbean class:

    
package com.strutsexample.form;
import com.strutsexample.model.Content;
import java.sql.Blob;
import org.apache.struts.action.ActionForm;
import org.apache.struts.upload.FormFile;
 
public class ContentForm extends ActionForm{
    
    private String name;
    private String title;
    private String content;
    private String filename;
    private FormFile file;
   /** Creates a new instance of ContentForm */
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public String getTitle() {
        return title;
    }
 
    public void setTitle(String title) {
        this.title = title;
    }
 
    public String getContent() {
        return content;
    }
 
    public void setContent(String content) {
        this.content = content;
    }
 
    public String getFilename() {
        return filename;
    }
 
    public void setFilename(String filename) {
        this.filename = filename;
    }
 
    public FormFile getFile() {
        return file;
    }
 
    public void setFile(FormFile file) {
        this.file = file;
    }
  
}

my struts action class:

 public class ContentAction extends DispatchAction{
    /* forward name="success" path="" */
    private final static String SUCCESS = "success";
    public ActionForward insert(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response)
            throws Exception{
        //System.out.println("action");
        ContentForm cfrm = (ContentForm) form;
        FormFile fFile;
        HibernateSessionFactory.getSessionFactory().getCurrentSession().beginTransaction();
        //Create new instance of Contact and set values in it by reading them from form object
       // System.out.println("Inserting Record");        
        /*Content content = new Content();
        content.setContent("contents");
        content.setName("submitted by");
        content.setFile("");
        content.setTitle("title of article");*/
        Content content=new Content();
        FormFile myFile   = (FormFile) cfrm.getFile();
        content.setContent(cfrm.getContent());
        content.setName(cfrm.getName());     
        content.setTitle(cfrm.getTitle());
       // content.setFilename(cfrm.getFilename());
       content.setFile(Hibernate.createBlob (myFile.getInputStream()));
        
        HibernateSessionFactory.getSessionFactory().getCurrentSession().save(content);       
        HibernateSessionFactory.getSessionFactory().getCurrentSession().getTransaction().commit();
       // System.out.println("Done");  
        
        return mapping.findForward(SUCCESS);
    }
   

[Merrill Higginson]

The Stack trace tells you that a NullPointerException is occuring at line 51 of your ContentAction class. Find which object is being dereferenced at line 51. That's the object that is null when you aren't expecting it to be. Then find out why it's null.

[lynn fann]

this is the line:
content.setFile(Hibernate.createBlob (myFile.getInputStream()));

[Merrill Higginson]

myFile must be null. Find out why.

Here's one thing you may want to check: If the size of the file is greater than what you specified in your struts-config.xml file in <controller maxFileSize="" /> Struts will not upload the file and the property in your ActionForm will be null.
[ March 12, 2007: Message edited by: Merrill Higginson ]