Wrapper class and CSV file upload

importDataFromCSV

<apex:page controller="importDataFromCSVController_mann">
    <apex:form >
        <apex:pagemessages />
        <apex:pageBlock >
            <apex:pageBlockSection columns="4">
                  <apex:inputFile value="{!csvFileBody}"  filename="{!csvAsString}"/>
                  <apex:commandButton value="Import Account" action="{!importCSVFile}"/>
            </apex:pageBlockSection>
        </apex:pageBlock>
        <apex:pageBlock >
           <apex:pageblocktable value="{!Accounts}" var="acc">
              <apex:column value="{!acc.acc.name}" />
              <apex:column value="{!acc.acc.AccountNumber}" />
              <apex:column value="{!acc.acc.Type}" />
              <apex:column value="{!acc.acc.Accountsource}" />
              <apex:column value="{!acc.acc.Industry }" />
               <apex:column headerValue="Status" >
              <apex:outputText id="status" value="{!acc.csvStatus}"/>
              </apex:column>
           </apex:pageblocktable>
        </apex:pageBlock>
   </apex:form>
</apex:page>

importDataFromCSVController_mann.cls

public class importDataFromCSVController_mann {
    /*
    The controller will read the file uploaded in CSV format (no headers)
    and check if the accounts exist in current org. Accordingly update the
    status field  
    
    */
    public Blob csvFileBody{get;set;}
    public string csvAsString{get;set;}
    public string csvStatus{get;set;}
    public String[] csvFileLines{get;set;}
    public string[] csvRecordData;
    public List<account> acc_lst;
    public Map<String,String> acc_map;
    
    
    
    //define a wrapper class
    public class wrapAccount {
        public Account acc {get;set;}
        public String csvStatus {get;set;}
        
        public wrapAccount(Account a, Map<String,String> acc_map) {
            acc = a;
            if(acc_map.containsKey(a.Name)) {
                csvStatus = 'Duplicate';
            } else {
                csvStatus = 'Unique';
                //write you insert statement here (am commenting it to keep my DB clean :))
                //insert a;
                
            }
            
        }
    }
    
    //wrapperobject to display on VF
    public List<wrapAccount> wrapAccount_lst {get;set;}
    
    
    public List<wrapAccount> getAccounts() {
        return wrapAccount_lst;
    }
    
    //populate wrapperObject
    public pagereference importCSVFile() {
        csvAsString = csvFileBody.toString();
        csvFileLines = csvAsString.split('\n');
        system.debug('csvFileLines= '+csvFileLines+' csvFileLines.size() = '+csvFileLines.size());
        
        //get all accounts
        acc_lst = new List<account>([select Name, Accountnumber from account]);
        //initialize the map
        acc_map = new Map<String,String>();
        
        for (account a: acc_lst) {
            system.debug('a = '+a);
            acc_map.put(a.Name,a.AccountNumber);
        }
          
        wrapAccount_lst = new List<wrapAccount>();
        for(Integer i=0;i<csvFileLines.size();i++) { //assuming no header in the CSV
            
            Account a = new Account();
			csvRecordData = csvFileLines[i].split(',');
            a.name = csvRecordData[0] ;            
            a.accountnumber = csvRecordData[1];
            a.Type = csvRecordData[2];
            a.AccountSource = csvRecordData[3];  
            a.Industry = csvRecordData[4];
            
            
            wrapAccount_lst.add(new wrapAccount(a,acc_map));
             
        }
        return null;
    }
 

}