1、首先注册一个163邮箱

自己的邮箱地址是xyqq769552629@163.com

登陆的密码是自己设定

使用邮箱发邮件，邮件必须开启pop和smtp服务，登陆邮件

开启SMTP服务，这个时候提示你必须设置授权的密码，

pom依赖：

                    <dependency>  
            <groupId>activation</groupId>  
            <artifactId>activation</artifactId>  
            <version>1.0.2</version>  
        </dependency>

        <dependency>  
            <groupId>activation</groupId>  
            <artifactId>activation</artifactId>  
            <version>1.0.2</version>  
        </dependency>

实现代码如下：

1、controller：

@RequestMapping("/RegisterServlet")
public ModelAndView RegisterServlet(String username,String password,String email) throws Exception {
ModelAndView mv = new ModelAndView();
try{

        usermail user = new usermail();  
        user.setEmail(email);  
        user.setPassword(password);  
        user.setUsername(username);

        System.out.println("把用户信息注册到数据库中");  
        //用户注册成功之后就使用用户注册时的邮箱给用户发送一封Email  
        //发送邮件是一件非常耗时的事情，因此这里开辟了另一个线程来专门发送邮件  
        Sendmail send = new Sendmail(user);  
        //启动线程，线程启动之后就会执行run方法来发送邮件  
        send.start();

        //注册用户  
        //new UserService().registerUser(user);  
        mv.addObject("message", "恭喜您，注册成功，我们已经发了一封带了注册信息的电子邮件，请查收，如果没有收到，可能是网络原因，过一会儿就收到了！！");  
        mv.setViewName("message");  
    }catch (Exception e) {  
        e.printStackTrace();  
        mv.addObject("message", "注册失败！！");  
        mv.setViewName("message");  
    }  
    return mv;  
}

2、Sendmail

package com.sihai.utils;
import java.util.Properties;
import javax.mail.Message;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

import com.sihai.pojo.usermail;

/**
* @ClassName: Sendmail
* @Description: Sendmail类继承Thread，因此Sendmail就是一个线程类，这个线程类用于给指定的用户发送Email
* @author: xyq
* @date: 2015-1-12 下午10:43:48
*
*/
public class Sendmail extends Thread {
//用于给用户发送邮件的邮箱
private String from = "xxxx@163.com";
//邮箱的用户名
private String username = "xxxxx";
//邮箱的密码//163的授权密码
private String password = "xxxxxxxx";
//发送邮件的服务器地址
private String host = "smtp.163.com";

private usermail user;  
public Sendmail(usermail user){  
    this.user = user;  
}

/\* 重写run方法的实现，在run方法中发送邮件给指定的用户  
 \* @see java.lang.Thread#run()  
 \*/  
@Override  
public void run() {  
    try{  
        Properties prop = new Properties();  
        prop.setProperty("mail.host", host);  
        prop.setProperty("mail.transport.protocol", "smtp");  
        prop.setProperty("mail.smtp.auth", "true");  
        Session session = Session.getInstance(prop);  
        session.setDebug(true);  
        Transport ts = session.getTransport();  
        ts.connect(host, username, password);  
        Message message = createEmail(session,user);  
        ts.sendMessage(message, message.getAllRecipients());  
        ts.close();  
    }catch (Exception e) {  
        throw new RuntimeException(e);  
    }  
}

/\*\*  
\* @Method: createEmail  
\* @Description: 创建要发送的邮件  
\* @Anthor:孤傲苍狼  
\*  
\* @param session  
\* @param user  
\* @return  
\* @throws Exception  
\*/  
public Message createEmail(Session session,usermail user) throws Exception{

    MimeMessage message = new MimeMessage(session);  
    message.setFrom(new InternetAddress(from));  
    message.setRecipient(Message.RecipientType.TO, new InternetAddress(user.getEmail()));  
    message.setSubject("用户注册邮件");

    String info = "恭喜您注册成功，您的用户名：" + user.getUsername() + ",您的密码：" + user.getPassword() + "，请妥善保管，如有问题请联系网站客服!!";  
    message.setContent(info, "text/html;charset=UTF-8");  
    message.saveChanges();  
    return message;  
}  

}

3、usermail

package com.sihai.pojo;

public class usermail {
private String username;
private String password;
private String email;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}

4、register.jsp

<%@ page language="java" pageEncoding="UTF-8"%>

用户名：
密码：
邮箱：

5、message.jsp

<%@ page language="java" pageEncoding="UTF-8"%>

${message}

到这里基本就实现了发送邮件