File Upload

=============VFPages==================
<apex:page controller="fileupload">
 <apex:sectionHeader title="fileupload"/>
  <apex:form enctype="format-data">
   <apex:pageBlock title="upload a file">
    <apex:pageBlockButtons >
         <apex:commandButton value="save" action="{!upload}"/>
    </apex:pageBlockButtons>
    <apex:pageBlockSection showHeader="true" columns="2" id="Block1">
         <apex:pageBlockSectionItem >
           <apex:outputLabel value="file name" for="filename">
               <apex:inputText value="{!Documentname}" id="filename"/>
           </apex:outputLabel>
         </apex:pageBlockSectionItem>
         <apex:pageBlockSectionItem >
          <apex:outputLabel value="file discription" for="file discription">
          <apex:inputFile value="{!DoBody}" fileName="{!Documentname}" id="file">
          </apex:inputFile>
          </apex:outputLabel>
        </apex:pageBlockSectionItem>
        <apex:pageBlockSectionItem >
           <apex:outputLabel value="Description" for="description" />
           <apex:inputTextarea value="{!dodescription}" id="description" />
        </apex:pageBlockSectionItem>
        <apex:pageBlockSectionItem >
          <apex:outputLabel value="Keywords" for="Keywords">
          <apex:inputText value="{!DoKeywords}" id="Keywords"/>
          </apex:outputLabel>
        </apex:pageBlockSectionItem>
        </apex:pageBlockSection>
    </apex:pageBlock>
  </apex:form>
</apex:page>
===========Controller=======================
public with sharing class fileupload {

    public String DoKeywords { get; set; }

    public String dodescription { get; set; }

    public String DoBody { get; set; }

    public String Documentname { get; set; }

   // public String Document {  set; }
    public Document document{
        get{
                if(document == null)
                document= new Document();
                return document;
        }
        set;
    }

    public PageReference upload() {
       // document.AuthorId = UserInfo.getUserId();
        //document.FolderId = UserInfo.getUserId();
        try{
            insert Document;
        }
        catch(DMLException e){
            ApexPages.addMessage(new ApexPages.message(ApexPages.severity.ERROR,'Error uploading file'));

        }
        finally {
            DoBody=null;
            Documentname=null;
            Document=new Document();
        }
        ApexPages.addMessage(new ApexPages.message(ApexPages.severity.INFO,'File uploaded successfully'));
        return null;
    }

}