使用IDEA實現郵件發送

2、郵件發送

原理：

編寫程序的四個核心類及程序流程：

需要的jar包：

簡單QQ郵件（無附件）發送代碼實現

//發送一封簡單的郵件
public class MailDemo01 {
    public static void main(String[] args) throws Exception {

        Properties prop = new Properties();
        prop.setProperty("mail.host","smtp.qq.com"); //設置QQ郵件服務器
        prop.setProperty("mail.transport.protocol","smtp"); //郵件發送協議
        prop.setProperty("mail.smtp.auth","true"); //需要驗證用戶名密碼

        //關於QQ郵箱，還要設置SSL加密，加上以下代碼即可
        MailSSLSocketFactory sf = new MailSSLSocketFactory();
        sf.setTrustAllHosts(true);
        prop.put("mail.smtp.ssl.enable","true");
        prop.put("mail.smtp.ssl.socketFactory",sf);

        //使用JavaMail發送郵件的5個步驟

        //1、創建定義整個應用程序所需的環境信息的Session對象
        Session session = Session.getDefaultInstance(prop, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                //發件人郵件用戶名、授權碼
                return new PasswordAuthentication("[e-mail]","****************");
            }
        });

        //開啟Session的debug模式，這樣就可以查看到程序發送Email的運行狀態
        session.setDebug(true);

        //2、通過session得到transport對象
        Transport ts = session.getTransport();

        //3、使用郵箱的用戶名和授權碼連上郵件服務器
        ts.connect("smtp.qq.com","[e-mail]","****************");

        //4、創建郵件：寫郵件
        //注意需要傳遞Session
        MimeMessage message = new MimeMessage(session);

        //指明郵件的發件人 24736743
        message.setFrom(new InternetAddress("[e-mail]"));

        //指明郵件的收件人，現在發件人和收件人是一樣的，那就是自己給自己發
        message.setRecipient(Message.RecipientType.TO,new InternetAddress("[e-mail]"));

        //郵件的標題
        message.setSubject("只包含文本的簡單郵件");

        //郵件的文本內容
        message.setContent("<h1 style='color:red'>你好啊！</h1>","text/html;charset=UTF-8");

        //5、發送郵件
        ts.sendMessage(message,message.getAllRecipients());

        //6、關閉連接
        ts.close();
    }
}

復雜QQ郵件（由附件）發送的實現

MIME（多用途互聯網郵件擴展類型）

MineBodyPart類

MineMultipart類

代碼實現：

public class MailDemo02 {
    public static void main(String[] args) throws Exception {

        Properties prop = new Properties();
        prop.setProperty("mail.host","smtp.qq.com"); //設置QQ郵件服務器
        prop.setProperty("mail.transport.protocol","smtp"); //郵件發送協議
        prop.setProperty("mail.smtp.auth","true"); //需要驗證用戶名密碼

        //關於QQ郵箱，還要設置SSL加密，加上以下代碼即可
        MailSSLSocketFactory sf = new MailSSLSocketFactory();
        sf.setTrustAllHosts(true);
        prop.put("mail.smtp.ssl.enable","true");
        prop.put("mail.smtp.ssl.socketFactory",sf);

        //使用JavaMail發送郵件的5個步驟

        //1、創建定義整個應用程序所需的環境信息的Session對象
        Session session = Session.getDefaultInstance(prop, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                //發件人郵件用戶名、授權碼
                return new PasswordAuthentication("[e-mail]","****************");
            }
        });

        //開啟Session的debug模式，這樣就可以查看到程序發送Email的運行狀態
        session.setDebug(true);

        //2、通過session得到transport對象
        Transport ts = session.getTransport();

        //3、使用郵箱的用戶名和授權碼連上郵件服務器
        ts.connect("smtp.qq.com","[e-mail]","****************");

        //4、創建郵件：寫郵件
        //注意需要傳遞Session
        MimeMessage message = new MimeMessage(session);

        //指明郵件的發件人 24736743
        message.setFrom(new InternetAddress("[e-mail]"));

        //指明郵件的收件人，現在發件人和收件人是一樣的，那就是自己給自己發
        message.setRecipient(Message.RecipientType.TO,new InternetAddress("[e-mail]"));

        //郵件的標題
        message.setSubject("復雜的郵件");
        //===================================================================================
        //准備圖片數據
        MimeBodyPart image = new MimeBodyPart();
        //圖片需要經過數據處理... DataHandler：數據處理
        DataHandler dh = new DataHandler(new FileDataSource("C:\\Users\\wangyudong\\Desktop\\1.png"));
        image.setDataHandler(dh);//在我們的body中放入這個處理的圖片數據
        image.setContentID("bz.jpg");//給圖片設置一個ID，我們在后面可以使用

        //准備正文數據
        MimeBodyPart text = new MimeBodyPart();
        text.setContent("這是一封郵件正文帶圖片<img src='cid:bz.jpg'>的郵件","text/html;charset=UTF-8");

        //描述數據關系
        MimeMultipart mm = new MimeMultipart();
        mm.addBodyPart(text);
        mm.addBodyPart(image);
        mm.setSubType("related");

        //設置到消息中，保存修改
        message.setContent(mm);//把最后編輯好的郵件放到消息當中
        message.saveChanges();//保存修改！

        //=================================================================

        //5、發送郵件
        ts.sendMessage(message,message.getAllRecipients());

        //6、關閉連接
        ts.close();
    }
}
====================================================================================
public class MailDemo03 {
    public static void main(String[] args) throws Exception {

        Properties prop = new Properties();
        prop.setProperty("mail.host","smtp.qq.com"); //設置QQ郵件服務器
        prop.setProperty("mail.transport.protocol","smtp"); //郵件發送協議
        prop.setProperty("mail.smtp.auth","true"); //需要驗證用戶名密碼

        //關於QQ郵箱，還要設置SSL加密，加上以下代碼即可
        MailSSLSocketFactory sf = new MailSSLSocketFactory();
        sf.setTrustAllHosts(true);
        prop.put("mail.smtp.ssl.enable","true");
        prop.put("mail.smtp.ssl.socketFactory",sf);

        //使用JavaMail發送郵件的5個步驟

        //1、創建定義整個應用程序所需的環境信息的Session對象
        Session session = Session.getDefaultInstance(prop, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                //發件人郵件用戶名、授權碼
                return new PasswordAuthentication("[e-mail]","****************");
            }
        });

        //開啟Session的debug模式，這樣就可以查看到程序發送Email的運行狀態
        session.setDebug(true);

        //2、通過session得到transport對象
        Transport ts = session.getTransport();

        //3、使用郵箱的用戶名和授權碼連上郵件服務器
        ts.connect("smtp.qq.com","[e-mail]","****************");

        //4、連接上之后我們需要發送郵件；
        MimeMessage mimeMessage = imageMail(session);

        //5、發送郵件
        ts.sendMessage(mimeMessage,mimeMessage.getAllRecipients());

        //6、關閉連接
        ts.close();
    }

    public static MimeMessage imageMail(Session session) throws MessagingException{

        //消息的固定信息
        MimeMessage mimeMessage = new MimeMessage(session);

        //指明郵件的發件人 24736743
        mimeMessage.setFrom(new InternetAddress("[e-mail]"));

        //指明郵件的收件人，現在發件人和收件人是一樣的，那就是自己給自己發
        mimeMessage.setRecipient(Message.RecipientType.TO,new InternetAddress("[e-mail]"));

        //郵件的標題
        mimeMessage.setSubject("我也不知道是個什么東西就發給你了");

        /*
        編寫郵件的內容
        1.圖片
        2.附件
        3.文本
         */

        //圖片
        MimeBodyPart body1 = new MimeBodyPart();
        body1.setDataHandler(new DataHandler(new FileDataSource("C:\\Users\\wangyudong\\Desktop\\1.png")));
        body1.setContentID("yhbxb.png");//圖片設置ID

        //文本
        MimeBodyPart body2 = new MimeBodyPart();
        body2.setContent("請注意，我不是廣告","text/html;charset=utf-8");

        //附件
        MimeBodyPart body3 = new MimeBodyPart();
        body3.setDataHandler(new DataHandler(new FileDataSource("C:\\Users\\wangyudong\\Desktop\\1.png")));
        body3.setFileName("1.png");//附件設置名字

        MimeBodyPart body4 = new MimeBodyPart();
        body4.setDataHandler(new DataHandler(new FileDataSource("C:\\Users\\wangyudong\\Desktop\\1.sql")));
        body4.setFileName("");//附件設置名字

        //拼裝郵件正文內容
        MimeMultipart multipart1 = new MimeMultipart();
        multipart1.addBodyPart(body1);
        multipart1.addBodyPart(body2);
        multipart1.setSubType("related");//1.文本和圖片內嵌成功

        //new MimeBodyPart().setContent(multipart1); //將拼裝好的正文內容設置為主體
        MimeBodyPart contentText = new MimeBodyPart();
        contentText.setContent(multipart1);

        //拼接附件
        MimeMultipart allFile = new MimeMultipart();
        allFile.addBodyPart(body3);//附件
        allFile.addBodyPart(body4);//附件
        allFile.addBodyPart(contentText);//正文
        allFile.setSubType("mixed");//正文和附件都存在郵件中，所有類型設置為mixed

        //放到Message消息中
        mimeMessage.setContent(allFile);
        mimeMessage.saveChanges();

        return mimeMessage;
    }
}

3、網站注冊發送郵件的代碼實現

准備文件：

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
    <!--Servlet 依賴-->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
    </dependency>
    <!--JSP依賴-->
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.2</version>
    </dependency>
    <!--standard標簽庫-->
    <dependency>
        <groupId>taglibs</groupId>
        <artifactId>standard</artifactId>
        <version>1.1.2</version>
    </dependency>
    <!--JSTL表達式的依賴-->
    <dependency>
        <groupId>javax.servlet.jsp.jstl</groupId>
        <artifactId>jstl-api</artifactId>
        <version>1.2</version>
    </dependency>
    <!--連接數據庫-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.16</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
        <version>1.2.79</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
    <dependency>
        <groupId>commons-fileupload</groupId>
        <artifactId>commons-fileupload</artifactId>
        <version>1.4</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
    <dependency>
        <groupId>commons-io</groupId>
        <artifactId>commons-io</artifactId>
        <version>2.11.0</version>
    </dependency>
</dependencies>
======================================================================================
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
    <form action="${pageContext.request.contextPath}/RegisterServlet.do" method="post">
      用戶名：<input type="text" name="username"><br/>
      密碼：<input type="password" name="password"><br/>
      郵箱：<input type="text" name="email"><br/>
      <input type="submit" value="注冊">
    </form>
  </body>
</html>
=====================================================================================
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

<h1>xxx網站溫馨提示</h1>
${message}

</body>
</html>
======================================================================================
<?xml version="1.0" encoding="UTF-8"?>
<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>com.kuang.servlet.RegisterServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>RegisterServlet</servlet-name>
        <url-pattern>/RegisterServlet.do</url-pattern>
    </servlet-mapping>
</web-app>

代碼實現：

public class User implements Serializable {
    private String username;
    private String password;
    private String email;

    public User() {
    }

    public User(String username, String password, String email) {
        this.username = username;
        this.password = password;
        this.email = 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;
    }

    @Override
    public String toString() {
        return "User{" +
                "username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}
===================================================================================
//網站3秒原則：用戶體驗
//多線程實現用戶體驗！ 異步處理
public class SendMail extends Thread{

    //用於給用戶發送郵件的通知
    private String from = "[e-mail]";
    //郵箱的用戶名
    private String username = "[e-mail]";
    //郵箱的密碼
    private String password = "****************";
    //發送郵件的服務器地址
    private String host = "smtp.qq.com";

    private User user;
    public SendMail(User user){
        this.user = user;
    }

    //重寫run方法的實現，在run方法中發送郵件給指定的用戶
    @Override
    public void run() {
        try {
            Properties prop = new Properties();
            prop.setProperty("mail.host",host); //設置QQ郵件服務器
            prop.setProperty("mail.transport.protocol","smtp"); //郵件發送協議
            prop.setProperty("mail.smtp.auth","true"); //需要驗證用戶名密碼

            //關於QQ郵箱，還要設置SSL加密，加上以下代碼即可
            MailSSLSocketFactory sf = new MailSSLSocketFactory();
            sf.setTrustAllHosts(true);
            prop.put("mail.smtp.ssl.enable","true");
            prop.put("mail.smtp.ssl.socketFactory",sf);

            //使用JavaMail發送郵件的5個步驟

            //1、創建定義整個應用程序所需的環境信息的Session對象
            Session session = Session.getDefaultInstance(prop, new Authenticator() {
                protected PasswordAuthentication getPasswordAuthentication() {
                    //發件人郵件用戶名、授權碼
                    return new PasswordAuthentication("[e-mail]","****************");
                }
            });

            //開啟Session的debug模式，這樣就可以查看到程序發送Email的運行狀態
            session.setDebug(true);

            //2、通過session得到transport對象
            Transport ts = session.getTransport();

            //3、使用郵箱的用戶名和授權碼連上郵件服務器
            ts.connect("smtp.qq.com","[e-mail]","****************");

            //4、創建郵件：寫郵件
            //注意需要傳遞Session
            MimeMessage message = new MimeMessage(session);

            //指明郵件的發件人 24736743
            message.setFrom(new InternetAddress("[e-mail]"));

            //指明郵件的收件人，現在發件人和收件人是一樣的，那就是自己給自己發
            message.setRecipient(Message.RecipientType.TO,new InternetAddress(user.getEmail()));

            //郵件的標題
            message.setSubject("只包含文本的簡單郵件");

            String info = "恭喜您注冊成功，您的用戶名："+user.getUsername()+"，您的密碼："+user.getPassword()+"，請妥善保管，如有問題請聯系網站客服！！";

            //郵件的文本內容
            message.setContent(info,"text/html;charset=UTF-8");
            message.saveChanges();

            //5、發送郵件
            ts.sendMessage(message,message.getAllRecipients());

            //6、關閉連接
            ts.close();
        }catch (Exception e){
            throw new RuntimeException(e);
        }
    }
}
==================================================================================
public class RegisterServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //接受用戶請求，封裝成對象
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String email = req.getParameter("email");

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

        //用戶注冊成功之后，會給用戶發送一封郵件
        //我們使用線程來專門發送郵件，防止出現耗時，和網絡注冊人數過多的情況
        SendMail send = new SendMail(user);
        //啟動線程，線程啟動之后就會執行run方法來發送郵件
        //send.run();為不使用多線程，頁面反應較慢
        send.start();//使用多線程進行操作

        //注冊用戶
        req.setAttribute("message","注冊成功，我們已經發送了一封帶了注冊信息的電子郵件，請查收！如網絡不穩定，可能過會才能收到！！");
        req.getRequestDispatcher("info.jsp").forward(req,resp);
    }
}