Save an attachment in APEX

Example for save an attachment in APEX.

APEX CODE:

public class status{
private final Applicant__c applicant;
public Blob resume {get; set;}
public String contentType {get; set;}
public String fileName {get; set;}

public status(ApexPages.StandardController stdController) {
this.applicant=(Applicant__c)stdController.getRecord();
}
public PageReference saveApplication() {

  try{
        insert(applicant);                                      
   }catch(System.DMLException e){
      ApexPages.addMessages(e);
       return null;
}

if(resume!=null){
      Attachment attach=new Attachment();
      attach.Body=resume;
      attach.Name=filename;
      attach.ContentType=contentType;
      attach.ParentID=applicant.id;
    try {
          insert(attach);
      } catch(System.DMLException e) {
          ApexPages.addMessages(e);
          return null;
      }
  }
  PageReference p = Page.Confirmpage;
        p.setRedirect(true);
        return p;                   
}
}

VISUALFORCE PAGE:

 <apex:page standardController="Applicant__c" extensions="status">
<apex:form >
<table>
<tr>
<td>Applicant Name </td>
<td><apex:inputField value="{!Applicant__c.Name__c}"/></td>
</tr>
<tr>
<td>CV </td>
<td> <apex:inputFile accept="doc, txt, pdf" filename="{!fileName}" contentType="{!contentType}" filesize="1000" size="50" value="{!resume}"/> </td>
</tr>
<tr>
<td></td>
<td><apex:commandButton id="submitApplicant" value="Submit" action="{!saveApplication}"/></td>
</tr>
</table>
</apex:form>
</apex:page>