How to send Email notifications template in AEM

The process involves three steps.

We can send an email template by using the workflow also. But this is the process without using the workflow.
For this,

1) We need to interact with the form, for the values which are required to pass to the mail template.
2)Sending the values to the servlet by using Ajax call
3)Interact with the servlet and inject values into the mail template using the appropriate methods.

Here is the code to sending an email template.

package com.test.mailtemp;

/*
*Author SONYC
*
*/
import java.util.HashMap;
import java.util.Map;
import java.io.*;
import java.util.ArrayList;
import javax.jcr.Node;
import javax.jcr.Session;
import javax.mail.MessagingException;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.servlet.ServletException;
import javax.servlet.Servlet;
import com.day.cq.commons.mail.MailTemplate;
import com.day.cq.mailer.MessageGateway;
import com.day.cq.mailer.MessageGatewayService;
import org.apache.commons.lang.text.StrLookup;
import org.apache.commons.mail.EmailException;
import org.apache.commons.mail.HtmlEmail;
import org.apache.felix.scr.annotations.*;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceResolver;
import org.apache.sling.api.resource.ResourceResolverFactory;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.jcr.api.SlingRepository;
import org.apache.sling.api.servlets.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@SuppressWarnings({"deprecation", "serial"})
@Component
@Service(Servlet.class)
@Properties(value = {
    @Property(name = "sling.servlet.paths", value = "/bin/emaitempcall.html")
})
public class mailtemp extends SlingAllMethodsServlet{ 
   
    private static final Logger log = LoggerFactory.getLogger(mailtemp.class);    
    ArrayList<InternetAddress> emailRecipients = new ArrayList<InternetAddress>();  
    @Reference
    private MessageGatewayService messageGatewayService;   
    @Reference
    private MessageGateway<HtmlEmail> messageGateway;   
    @Reference
    private ResourceResolverFactory serviceRef;
    private ResourceResolver resResolve = null;   
    String param1,param2=null;   
    private Session session;  
   
    @Reference
    public SlingRepository repository;
   
    @Override
    protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) throws ServletException,IOException {       
        init(request, response);
    }
   
    @Override
    protected void doPost(SlingHttpServletRequest request, SlingHttpServletResponse response) throws ServletException,IOException {       
        init(request, response);
    }
   
    @SuppressWarnings("static-access")
    private void init(SlingHttpServletRequest request, SlingHttpServletResponse response ){    
     
            //Additional code here regaring the value updation in repository/any functionality
     mailCall(param1, param2);         
    }   
    public void mailCall(String param1, String param2){      
        try{
        session = repository.loginAdministrative(null);
        Resource templateRsrc;
        HtmlEmail email = new HtmlEmail();
        String msg = "Hello, Our testing has completed here you got the mail !!!";

        Map<String, String> mailTokens = new HashMap<String, String>();
        mailTokens.put("subject", "Testing the mail template");
        mailTokens.put("param1", param1);
        mailTokens.put("param2", param2);
        mailTokens.put("thanks", "Thanks");
        mailTokens.put("author", "SONY C.");       
        mailTokens.put("message",msg);  
         
            templateRsrc = serviceRef.getAdministrativeResourceResolver(null).getResource("/etc/workflow/email");
            templateRsrc = templateRsrc.getChild("templatestructure.html");
            final MailTemplate mailTemplate = MailTemplate.create(templateRsrc.getPath(), session);
            String recipientName = "sonycharan004@gmail.com";
            String sendTo = "sonycharan004@gmail.com";
            String recName = "Sony C";
        
            mailTokens.put("contactName", "Dear "+recipientName);

            emailRecipients.add(new InternetAddress(sendTo) );
            email = mailTemplate.getEmail(StrLookup.mapLookup(mailTokens),HtmlEmail.class);
            email.setTo( emailRecipients );
        
            messageGateway = this.messageGatewayService.getGateway(HtmlEmail.class);
            messageGateway.send(email);
        
        }
        catch (AddressException e) {           
            e.printStackTrace();
        }catch (MessagingException e) {          
            e.printStackTrace();        
        } catch (EmailException e) {         
            e.printStackTrace();
        }
        catch(Exception e)  {
            e.printStackTrace();         
        }finally{
        session.logout();
        }
    }
   
}

II)As mentioned above we need to create a mail template in the path "/etc/workflow/email"  and under this create a file named "templatestructure.html"

Template Structure would be----

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
 <title>Tempate Demo</title>
</head>
<body topmargin="0" bottommargin="0">

Dear  ${contactName},

Sub: ${subject},
${message}.
And your text will be  ${param1}, ${param2}.
Thanks for Using my blog!!! For further updates please be in touch with <a href="http://sonycharan.blogspot.in/">Sonycharan blogspot</a>.

Thanks,
${author}.

<p style="margin:10px 10px 10px 0; padding:0px; line-height:20px;"><font style="font-family:Arial;color:#fefeff;font-size:11px;">
© 2013 SonyBlog. All rights reserved.</font></p> 
</body>
</html>