how to add a update button in the following jsp

Once the excel from the following jsp is loaded to the broswer, how to add a button in the jsp to allow the user to update the excel?

thanks,

<%@page import="java.io.*"%>
<%@page import="java.util.*"%>
<%@page import="org.apache.poi.xssf.usermodel.XSSFSheet"%>
<%@page import="org.apache.poi.xssf.usermodel.XSSFWorkbook"%>
<%@page import="org.apache.poi.xssf.usermodel.XSSFRow"%>
<%@page import="org.apache.poi.xssf.usermodel.XSSFCell"%>
<table border="1">
<%  
    short a=0;  
    short b=1;  
    short c=2;  
    short d=3;  
    int i=0;    
        String   value1="", value2="",value3=" ", value4="";    
        String filename ="C:/hello.xls";     
        if(filename != null && !filename.equals("")){
        try{    
        FileInputStream fs =new FileInputStream(filename);    
        XSSFWorkbook wb = new XSSFWorkbook(fs);   
        for(int k = 0; k < wb.getNumberOfSheets(); k++){    
         int j=i+1;    
         XSSFSheet sheet = wb.getSheetAt(k);    
         int rows  = sheet.getPhysicalNumberOfRows();    
         for(int r = 0; r < rows; r++){    
         XSSFRow row   = sheet.getRow(r);    
         int cells = row.getPhysicalNumberOfCells();    
         out.write("<br>");    
            XSSFCell cell1  = row.getCell(a);      
            value1 = cell1.getStringCellValue();   
            XSSFCell cell2  = row.getCell(b);     
            value2 = cell2.getStringCellValue();    
            XSSFCell cell3  = row.getCell(c);      
            value3 = cell3.getStringCellValue();    
            XSSFCell cell4  = row.getCell(d);     
            value4 = cell4.getStringCellValue();    
%>    
<tr><td><%=value1%></td><td><%=value2%></td><td><%=value3%></td><td><%=value4%></td></tr>    
<%    
}       
 i++;   
}    
}catch(Exception e){  
  System.out.println(e);   
 }   
 }   
 %>    
</table>