其找回密碼的流程如下：

第一步：輸入使用者名稱，系統查詢是否存在該使用者，如果存在則進行下一步，並給出使用者的郵箱；否則提示"不存在該使用者"

第二步：存在該使用者後，則進行使用者的郵箱驗證，每個使用者繫結一個QQ郵箱，點選"傳送驗證碼"按鈕，系統會給該郵箱傳送一條包含驗證碼的郵件，傳送成功，系統會在前端顯示"驗證碼已經發送到你的郵箱，請檢視"。使用者填入該驗證碼，並且兩者相匹配，則可以進行下一步，否則無法進行下一步，會提示"輸入的郵箱驗證碼錯誤"

第三步：檢視郵箱收到的郵件，複製驗證碼，填入系統第二步框中，進行第三步驗證。通過前兩步的驗證，已經可以驗證，操作者就是本人，所以第三步，使用者可以直接修改密碼，覆蓋原密碼

第四步：成功找回密碼，是一個新的密碼，使用者可以返回登入頁面進行登入

部分原始碼：

MailUtil.java(傳送郵件工具類)

package com.utils;

import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMessage.RecipientType;

/*
 * 管理員傳送郵件的配置類
 * 作者：海哥
 * 時間：2017年8月20日
 */
public class MailUtil {
   public void SendMessage(String receiver, String title, String content)
   		    throws AddressException,MessagingException{
       Properties properties = new Properties();
       properties.put("mail.transport.protocol", "smtp");// 連線協議
       properties.put("mail.smtp.host", "smtp.qq.com");// 主機名
       properties.put("mail.smtp.port", 465);// 埠號 
       properties.put("mail.smtp.auth", "true");
       properties.put("mail.smtp.ssl.enable", "true");//設定是否使用ssl安全連線  ---一般都使用
       properties.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
       properties.put("mail.smtp.socketFactory.port", "465");
       properties.put("mail.debug", "true");//設定是否顯示debug資訊  true 會在控制檯顯示相關資訊
       //得到回話物件
       Session session = Session.getInstance(properties);
       // 獲取郵件物件
       Message message = new MimeMessage(session);
       //設定發件人郵箱地址
       message.setFrom(new InternetAddress("
 
[email protected]"));
       //設定收件人地址        
       message.setRecipients(RecipientType.TO,new InternetAddress[] { new InternetAddress(receiver) });
       //設定郵件標題
       message.setSubject(title);
       //設定郵件內容
       message.setText(content);
       //得到郵差物件
       Transport transport = session.getTransport();
       //連線自己的郵箱賬戶
       transport.connect("
 
[email protected]", "輸入你自己的授權碼");//密碼為剛才得到的授權碼
       //傳送郵件       
       transport.sendMessage(message, message.getAllRecipients());
       System.out.println("郵件正在傳送!");
   }
}

package com.servlet;

import java.io.IOException;

import javax.mail.MessagingException;
import javax.mail.internet.AddressException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.bean.User;
import com.utils.MailUtil;

@WebServlet("/SendMessage")
public class SendMessage extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    public SendMessage() {
        super();
        // TODO Auto-generated constructor stub
    }

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doPost(request, response);
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		//設定編碼  
        request.setCharacterEncoding("utf-8");  
        response.setCharacterEncoding("utf-8");  
        response.setHeader("Content-Type","text/html; charset=utf-8");  
        try {
        	  MailUtil mail = new MailUtil();
              int num = (int)((Math.random()*9+1)*100000);   //生成六位驗證碼隨機數
              request.getSession().setAttribute("num", num);   //設定東西儲存驗證碼
              User user = (User) request.getSession().getAttribute("finduser");  //得到修改密碼物件的Object
              String receiver = user.getUser_mail();
              String title = "員工找回密碼";
              String content = "這是高階驗證系統發來的郵件，你正在執行該系統找回密碼的操作，你的郵箱驗證碼為："+ String.valueOf(num) + ",請不要告訴別人哦！";
			  mail.SendMessage(receiver, title, content);
			  request.getSession().setAttribute("success","驗證碼已經發送到你的郵箱，請檢視！");   //設定東西儲存驗證碼
		} catch (AddressException e) {
			// TODO Auto-generated catch block
			System.out.println("驗證碼傳送失敗");
			e.printStackTrace();
		} catch (MessagingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
        
        request.getRequestDispatcher("SecondSteps.jsp").forward(request, response);
	}

}

package com.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.bean.User;

@WebServlet("/Validation")
public class Validation extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    public Validation() {
        super();
        // TODO Auto-generated constructor stub
    }

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doPost(request, response);
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		//設定編碼  
        request.setCharacterEncoding("utf-8");  
        response.setCharacterEncoding("utf-8");  
        response.setHeader("Content-Type","text/html; charset=utf-8");
        
        String email = request.getParameter("email");
        String fycodes = request.getParameter("fycodes");   //郵箱驗證碼
        int code = Integer.parseInt(fycodes);    //字串轉換為整形
        int num =  (int) request.getSession().getAttribute("num");  //得到剛傳送的郵箱驗證碼
        System.out.println("你的郵箱驗證碼為："+num);
        if(code == num){                                            //判斷輸入的驗證碼是否和郵箱收到的一致
        	System.out.println("驗證成功！");
      //  	request.getSession().removeAttribute("num");
        	request.getSession().removeAttribute("success");
        	request.getRequestDispatcher("ThirdSteps.jsp").forward(request, response);
        }
        else{
        	request.getSession().setAttribute("ValidaError", "輸入的郵箱驗證碼錯誤！");   //設定東西儲存驗證碼
        	request.getRequestDispatcher("SecondSteps.jsp").forward(request, response);
        }
        
	}

}