How to Upload excel sheet from Salesforce Visualforce pages?

Hello Vishant,

You can use CSV parser for this..please refer the below example code where I have created one Visualforce page from where I am uplaoding the excel file .csv and extracting the records data and mapping with object columns

please check and let me know if it helps you

page:

<apex:page sidebar="false" controller="UploadOpportunityScheduleLineItem">
<apex:form >
<apex:sectionHeader title="Upload data from CSV file"/>
<apex:pagemessages />
<apex:pageBlock >
<center>
<apex:inputFile value="{!contentFile}" filename="{!nameFile}" />
<apex:commandButton action="{!ReadFile}" value="Upload File" id="theButton" style="width:70px;"/>
<br/> <br/>
</center>

<apex:pageBlocktable value="{!mapUnmatchedSchedules}" var="mapID" title="Unmathed Lines of CSV file">
<apex:column headervalue="Opportunity Id">
{!mapUnmatchedSchedules[mapID][0]}
</apex:column>
<apex:column headervalue="Oportunnity Name">
{!mapUnmatchedSchedules[mapID][1]}
</apex:column>
<apex:column headervalue="Month">
{!mapUnmatchedSchedules[mapID][2]}
</apex:column>
<apex:column headervalue="Year">
{!mapUnmatchedSchedules[mapID][3]}
</apex:column>
<apex:column headervalue="Actualized Amount">
{!mapUnmatchedSchedules[mapID][4]}
</apex:column>
</apex:pageBlocktable>
</apex:pageBlock>
</apex:form>
</apex:page>
class

public with sharing class UploadOpportunityScheduleLineItem
{

// Global variables
public string nameFile{get;set;}
public Blob contentFile{get;set;}
List<Schedule__c> lstScheduleToUpdate = new List<Schedule__c>();
public Schedule__C objSchedule{get;set;}
//String array for taking csv data by line.
String[] filelines = new String[]{};
//string array for taking csv columns.
String[] fileColumns = new String[]{};

//set for storing all id's from csv.
set<String> opptoupload{get;set;}
//map for storing data from csv.
public map<String,String> mapOppIDMonthYearToAccAmount{get;set;}
public map<String, List<String>> mapUnmatchedSchedules{get;set;}

//Main constructor
public UploadOpportunityScheduleLineItem()
{
//Initalizing required objects.
objSchedule = new Schedule__c();
opptoupload = new set<String>();
mapOppIDMonthYearToAccAmount = new map<String,String>();
mapUnmatchedSchedules = new map<String, List<String>>();
}
//Method to read file content and check extension and file format.
public Pagereference ReadFile()
{
//If without selecting csv file you clicked on upload it will give error message.
if(nameFile == null)
{
ApexPages.Message errormsg = new ApexPages.Message(ApexPages.severity.ERROR,'You should select csv file to upload');
ApexPages.addMessage(errormsg);
return null;
}
//Taking file extension.
String extension = nameFile.substring(nameFile.lastIndexOf('.')+1);
//Checking if file extension is .csv.
if(extension == 'csv' ||extension == 'CSV')
{
nameFile=contentFile.toString();
//Spliting by new line
filelines = nameFile.split('\n');
//Spliting values by (,) for checking coloumn size
fileColumns = filelines[0].split(',');
//If column size is 5 then only it will proceed.
if(fileColumns.size() ==5)
{
for (Integer i=1;i<filelines.size();i++)
{
String[] inputvalues = new String[]{};
inputvalues = filelines[i].split(',');
opptoupload.add(inputvalues[0]);

mapOppIDMonthYearToAccAmount.put(inputvalues[0]+inputvalues[2]+inputvalues[3],inputvalues[4]);
mapUnmatchedSchedules.put(inputvalues[0]+inputvalues[2]+inputvalues[3],inputvalues);
lstScheduleToUpdate = new List<Schedule__c>();
}
for(Schedule__c objSchedule : [select Opportunity__r.Id ,Month__c,Year__c,
Actualized_Amount__c from Schedule__c where
Opportunity__c IN :opptoupload])
{
String str = objSchedule.Opportunity__r.Id;
String str1;
str1 = str.substring(0, 15);
if(mapOppIDMonthYearToAccAmount.containsKey(str1 + objSchedule.Month__c +objSchedule.Year__c))
{

objSchedule.Actualized_Amount__c = decimal.valueOf(mapOppIDMonthYearToAccAmount.get(str1 + objSchedule.Month__c +objSchedule.Year__c).trim());
mapUnmatchedSchedules.remove(str1 + objSchedule.Month__c +objSchedule.Year__c);
lstScheduleToUpdate.add(objSchedule);
}
}
//Checking if list is not empty then updating.
if(lstScheduleToUpdate.Size()>0)
{
update lstScheduleToUpdate;
}
ApexPages.Message errormsg = new ApexPages.Message(ApexPages.severity.info,'File uploaded successfully');
ApexPages.addMessage(errormsg);

return null;
}
else
{
ApexPages.Message errormsg = new ApexPages.Message(ApexPages.severity.ERROR,'There should be 5 columns in csv file');
ApexPages.addMessage(errormsg);
return null;
}
return null;
}
//If file is not csv type then it will give error message.
else
{
ApexPages.Message errormsg = new ApexPages.Message(ApexPages.severity.ERROR,'File type should be csv type');
ApexPages.addMessage(errormsg);
return null;
}
}
}

Also, please mark this as best answer if it solves your issue...let me know if anything else needed.