Java邮件发送

(Updated: )
Java

    • 介绍

    1. 传输协议

      • SMTP协议（Simple Mail Transfer Protocol）
        • 属于TCP/IP协议族
        • 控制信件的中转方式，帮助找到下一个目的地
        • SMTP邮件服务器
        • 发送协议
      • POP3协议（Post Office Protocol - version 3）
        • 属于TCP/IP协议族
        • 远程管理自己在服务器上的邮件
        • POP服务器
        • 接收协议（登录管理协议）

    2. 邮件服务器

      要在网络上实现邮件功能，要使用专门的邮件服务器。

      • SMTP服务器 ：一般是smtp.xxx.com。如163邮箱smtp.163.com，QQ邮箱smtp.qq.com。
      • POP服务器：一般是pop.xxx.com。如163邮箱pop.163.com，QQ邮箱pop.qq.com。

    邮件发送实现

    • 需要JavaMail API 和 Java Activation Framework

    • 对应两个jar包：mail.jar activation.jar

    • 要发送邮件 需要获得协议和支持 开启服务POP3/SMTP服务

    • 普通邮件：不包含附件和图片，纯文本邮件

    • 复杂邮件：非纯文本邮件

    • pom.xml
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     <!-- https://mvnrepository.com/artifact/javax.mail/mail -->
    <!--    <dependency>-->
    <!--      <groupId>javax.mail</groupId>-->
    <!--      <artifactId>mail</artifactId>-->
    <!--      <version>1.4.7</version>-->
    <!--    </dependency>-->
    <!--    上面那个包会出错 大概是ssl协议的问题 换成下下面这个包就可以了
    或者  打开java安装路径->jre/lib/security
    然后编辑java.security文件，把SSLv3跟TSL开头的都删掉，然后重启一下服务
    -->
        <!-- https://mvnrepository.com/artifact/com.sun.mail/javax.mail -->
        <dependency>
          <groupId>com.sun.mail</groupId>
          <artifactId>javax.mail</artifactId>
          <version>1.6.2</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/javax.activation/activation -->
        <dependency>
          <groupId>javax.activation</groupId>
          <artifactId>activation</artifactId>
          <version>1.1.1</version>
        </dependency>

    • 核心类介绍

      • Session对象

        定义整个程序所需环境信息，比如主机名、端口号、采用的邮件发送协议和接收协议

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        // 获取实例对象
        Session getDefaultInstance(Properties props)

        Session getDefaultInstance(Properties props, Authenticator authenticator)
            
        // 开启Debug模式
        void setDebug(boolean debug)
            
        // 获取Transport对象
        Transport getTransport()

      • Transport对象

        用来发送邮件

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        // 连接到邮件服务器
        void connect(String host, String user, String password)
            
        // 发送邮件
        void sendMessage(Message var1, Address[] var2)
            
        // 关闭连接
        void close()

      • Message对象

        表示一封电子邮件，被Transport对象引用

      • Store对象

        用来接收邮件，被Session对象引用，同时创建Message对象

      • MailSSLSocketFactory

        设置SSL加密

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        // SSL加密：QQ邮箱需要设置，通过以下4行代码
        MailSSLSocketFactory mssf = new MailSSLSocketFactory();
        mssf.setTrustAllHosts(true);
        prop.put("mail.smtp.ssl.enable", "true");
        prop.put("mail.smtp.ssl.socketFactory", mssf);

      • MimePart接口实现类：MimeMessage类

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        // 设置发件人
          void setFrom(Address address)
            
          // 设置收件人
          void setRecipient(Message.RecipientType type, Address address)
              
          // 设置主题
          void setSubject(String subject)
              
          // 设置内容
          void setContent(Object o, String type)
          
          // 保存修改：添加图片、附件时需要
          void saveChanges()

      • MimePart接口实现类：MimeBodyPart类

        复杂邮件所需

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        // 文本：设置内容
          void setContent(Object o, String type)

          // 图片、附件：设置数据处理
          void setDataHandler(DataHandler dh)
              
          // 图片：设置CID，在文本中通过src引用
          void setContentID(String cid)
          
          // 附件：设置附件名
          void setFileName(String filename)

      • MimePart接口实现类：MimeMultiPart类

        组合多个代表MIME消息的MimeBodyPart对象。

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        // 添加MIME消息
        void addBodyPart(BodyPart part)
          
        // 描述数据关系：alternative/related/mixed
        void setSubType(String subtype)

    • 步骤

      1. 创建Session对象
      2. 获得Transport对象
      3. 创建邮件（普通邮件和复杂邮件有区别）
      4. 发送Message，关闭连接

    Java实现

    • 发送简单邮件
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    package xyz.yiochin;

    import com.sun.mail.util.MailSSLSocketFactory;

    import javax.mail.*;
    import javax.mail.internet.InternetAddress;
    import javax.mail.internet.MimeMessage;
    import java.util.Properties;

    //发送简单邮件
    public class MailSend01 {
        public static void main(String[] args) throws Exception {
            Properties prop = new Properties();

            //set qq mail server
            prop.setProperty("mail.host","smtp.qq.com");
            //set send protocol
            prop.setProperty("mail.transport.protocol","smtp");
            //validate name and password
            prop.setProperty("mail.smtp.auth","true");

            //qq need ssl
            MailSSLSocketFactory sf = new MailSSLSocketFactory();
            sf.setTrustAllHosts(true);
            prop.put("mail.smtp.ssl.enable","true");
            prop.put("mail.smtp.ssl.socketFactory",sf);

            // use Java send a mail needs 5 steps
            // 1、创建定义整个应用程序所需要的环境信息的Session对象
            // qq needs others dont
            Session session = Session.getDefaultInstance(prop, new Authenticator() {
                @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    //username validation
                    return new PasswordAuthentication("****@qq.com","****");
                }
            });
            // 开始Session的debug模式可以看到程序发送email的运行状态
            session.setDebug(true);

            // 2、通过Session得到Transport对象
            Transport ts = session.getTransport();

            // 3、使用邮箱的用户名和授权码连上邮件服务器
            ts.connect("smtp.qq.com","****@qq.com", "****");


            // 4、创建邮件
            // 创建邮件对象
            MimeMessage message = new MimeMessage(session);

            // 指明邮件发件人
            message.setFrom(new InternetAddress("****@qq.com"));

            // 指明收件人
            message.setRecipient(Message.RecipientType.TO, new InternetAddress("****@163.com"));

            // 邮件的标题
            message.setSubject("This is a simple email sent by Java.");

            // 邮件的文本内容
            message.setContent("Hello World!","text/html;charset=UTF-8");

            // 5、发送邮件，关闭连接
            ts.sendMessage(message,message.getAllRecipients());

            ts.close();
        }
    }
    • 发送复杂邮件
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    package xyz.yiochin;

    import com.sun.mail.util.MailSSLSocketFactory;

    import javax.activation.DataHandler;
    import javax.activation.FileDataSource;
    import javax.mail.*;
    import javax.mail.internet.*;
    import java.security.GeneralSecurityException;
    import java.util.Properties;

    public class MailSend02 {
        public static void main(String[] args) throws Exception {
            MailSend02 mailSend02 = new MailSend02();
            mailSend02.sendMail();
        }

        void sendMail() throws MessagingException, GeneralSecurityException {
            // set properties
            final String host = "smtp.qq.com";
            final String authCode = "wlnjptkrsfuebhjc";
            final String addresser = "397040338@qq.com";
            final String addressee = "18326497503@163.com";

            //Configuration parameters
            Properties prop = new Properties();
            prop.setProperty("mail.host",host);
            prop.setProperty("mail.transport.protocol","smtp");
            prop.setProperty("mail.smtp.auth","true");

            // SSL
            MailSSLSocketFactory mailSSLSocketFactory = new MailSSLSocketFactory();
            mailSSLSocketFactory.setTrustAllHosts(true);
            prop.put("mail.smtp.ssl.enable","true");
            prop.put("mail.smtp.ssl.socketFactory",mailSSLSocketFactory);

            // 1、创建定义整个应用程序所需要的环境信息的Session对象
            Session session = Session.getDefaultInstance(prop, new Authenticator() {
                @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(addresser, authCode);
                }
            });

            //开启debug
            session.setDebug(true);

            // 2、通过Session得到Transport对象
            Transport ts = session.getTransport();

            // 3、使用邮箱的用户名和授权码连上邮件服务器
            ts.connect(host,addresser,authCode);

            // 4、创建邮件
            MimeMessage message = makeMixedMessage(session, addresser, addressee);

            // 5、发送邮件，关闭连接
            ts.sendMessage(message, message.getAllRecipients());

            ts.close();
        }

        //创建复杂邮件
        private MimeMessage makeMixedMessage(Session session,String addresser,String addressee) throws MessagingException {
            MimeMessage message = new MimeMessage(session);

            //sender
            message.setFrom(new InternetAddress(addresser));
            //receiver
            message.setRecipient(Message.RecipientType.TO,new InternetAddress(addressee));
            //subject
            message.setSubject("This is a mixed email");

            // text
            MimeBodyPart textPart = new MimeBodyPart();
            textPart.setContent("There is a picture to you: <img src='cid:img'>This","text/html;charset=utf-8");

            // picture
            MimeBodyPart imgPart = new MimeBodyPart();
            DataHandler dataHandler = new DataHandler(new FileDataSource("src\\main\\resources\\img\\img.png"));
            imgPart.setDataHandler(dataHandler);
            imgPart.setContentID("img");

            // attachment
            MimeBodyPart attachPart = new MimeBodyPart();
            DataHandler dataHandler1 = new DataHandler(new FileDataSource("src\\main\\resources\\md\\test.md"));
            attachPart.setDataHandler(dataHandler1);
            attachPart.setFileName("fileUpload.md");//have a suffix name better

            //describe data relationship：alternative/related/mixed
            MimeMultipart mm = new MimeMultipart();
            mm.addBodyPart(textPart);
            mm.addBodyPart(attachPart);
            mm.addBodyPart(imgPart);
            mm.setSubType("mixed");

            // set to MimeMessage message and save modification
            message.setContent(mm);
            message.saveChanges();

            return message;
        }
    }

    JavaWeb实现

    • 网站的注册功能通常有邮件的激活步骤，用到了邮件的发送
    • javax.mail、activation、servlet-api、jsp-api、jstl、lombok、junit

    • 目录结构：

      image-202203251626269654

      image-20220325162715911

    • 前端

      • register.jsp

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        <%@ page contentType="text/html;charset=UTF-8" language="java" %>
        <html>
        <body>
        <form action="register.do" method="post">
            <label>
                账号：<input type="text" name="username">
                <br>
            </label>
            <label>
                密码：<input type="password" name="password">
                <br>
            </label>
            <label>
                邮箱：<input type="text" name="mail">
                <br>
            </label>
            <input type="submit">|<input type="reset">
        </form>
        </body>
        </html>

      • seccess.jsp

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        <%--
          Created by IntelliJ IDEA.
          User: oho
          Date: 2022/3/25
          Time: 15:24
          To change this template use File | Settings | File Templates.
        --%>
        <%@ page contentType="text/html;charset=UTF-8" language="java" %>
        <html>
        <head>
            <title>成功</title>
        </head>
        <body>
        <h1>${msg}</h1>
        </body>
        </html>

    • Servlet

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      public class RegisterServlet extends HttpServlet {
          @Override
          protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
              String username = req.getParameter("username");
              String password = req.getParameter("password");
              String mailAddress = req.getParameter("mail");

              User user = new User(username, password, mailAddress);

              // 启动线程来发送邮件，优化注册等待时间
              MailThread mailThread = new MailThread(user);
              mailThread.start();//run只是调用方法 start才是开始多线程

              req.setAttribute("msg","注册成功，稍后会收到一封邮件");

              req.getRequestDispatcher("/WEB-INF/success.jsp").forward(req,resp);
          }

          @Override
          protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
              doGet(req, resp);
          }

      }

    • web.xml

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      <?xml version="1.0" encoding="UTF-8"?>
      <!--把这里的约束换成最新的-->
      <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
               xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
               xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
               http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
               version="4.0">
      <servlet>
        <servlet-name>RegisterServlet</servlet-name>
        <servlet-class>xyz.yiochin.servlet.RegisterServlet</servlet-class>
      </servlet>
        <servlet-mapping>
          <servlet-name>RegisterServlet</servlet-name>
          <url-pattern>/register.do</url-pattern>
        </servlet-mapping>
        <welcome-file-list>
          <welcome-file>/register.jsp</welcome-file>
        </welcome-file-list>
      </web-app>

    • 实体类：User

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      @Data
      @AllArgsConstructor
      @NoArgsConstructor
      public class User {
          private String username;
          private String password;
          private String mailAddress;
      }

    • 工具类：MailThread

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      public class MailThread extends Thread{
          final String host = "smtp.qq.com";
          final String authCode = "wlnjptkrsfuebhjc";
          final String addresser = "397040338@qq.com";
          final private User user;

          public MailThread(User user) {
              this.user = user;
          }

          @Override
          public void run() {
              try {
                  //配置参数
                  Properties prop = new Properties();
                  prop.setProperty("mail.host",host);
                  prop.setProperty("mail.transport.protocol","smtp");
                  prop.setProperty("mail.stmp.auth","true");

                  //SSL
                  MailSSLSocketFactory mailSSLSocketFactory = new MailSSLSocketFactory();
                  mailSSLSocketFactory.setTrustAllHosts(true);
                  prop.put("mail.smtp.ssl.enable","true");
                  prop.put("mail.stmp.ssl.socketFactory",mailSSLSocketFactory);

                  // 1、创建Session
                  Session session = Session.getDefaultInstance(prop, new Authenticator() {
                      @Override
                      protected PasswordAuthentication getPasswordAuthentication() {
                          return new PasswordAuthentication(addresser, authCode);
                      }
                  });

                  session.setDebug(true);
                  // 2、session 得到 transport
                  Transport ts = session.getTransport();

                  // 3、使用用户名和授权码链接服务器
                  ts.connect(host,addresser,authCode);
                  // 4、创建邮件
                  MimeMessage message = new MimeMessage(session);
                  message.setFrom(addresser);
                  message.setRecipient(Message.RecipientType.TO,new InternetAddress(user.getMailAddress()));
                  message.setSubject("用户注册邮件");

                  String info = "注册成功，您的用户名："+user.getUsername()+"，密码"+user.getPassword();
                  //test
                  System.out.println("=======================================");
                  System.out.println(user.getUsername() +":"+user.getPassword());
                  System.out.println("=======================================");


                  message.setContent(info,"text/html;charset=utf-8");

                  // 5、发送邮件，关闭连接
                  ts.sendMessage(message,new InternetAddress[]{new InternetAddress(user.getMailAddress())});
                  ts.close();
              } catch (GeneralSecurityException | MessagingException e) {
                  e.printStackTrace();
              }

          }
      }

    作者： Meow Mii

    本文链接： https://blog.yiochin.top/p/99746608.html

    版权声明： 本博客所有文章除特别声明外,均采用 CC BY-NC-ND 4.0 许可协议，转载请注明出处！

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