如何使用 GMail、Yahoo 或 Hotmail 通过 Java 应用程序发送电子邮件？

Question

是否可以使用Gmail帐户从我的Java应用程序发送电子邮件？我已经将公司邮件服务器配置为Java应用程序以发送电子邮件，但是当我分发应用程序时，这不会将其删除。任何使用Hotmail，Yahoo或Gmail的答案都是可以接受的。

Answer 1

首先下载 JavaMail API 并确保相关的 jar 文件位于您的类路径中。

这是使用 GMail 的完整工作示例。

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;

public class Main {

    private static String USER_NAME = "*****";  // GMail user name (just the part before "@gmail.com")
    private static String PASSWORD = "********"; // GMail password
    private static String RECIPIENT = "[email protected]";

    public static void main(String[] args) {
        String from = USER_NAME;
        String pass = PASSWORD;
        String[] to = { RECIPIENT }; // list of recipient email addresses
        String subject = "Java send mail example";
        String body = "Welcome to JavaMail!";

        sendFromGMail(from, pass, to, subject, body);
    }

    private static void sendFromGMail(String from, String pass, String[] to, String subject, String body) {
        Properties props = System.getProperties();
        String host = "smtp.gmail.com";
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.user", from);
        props.put("mail.smtp.password", pass);
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");

        Session session = Session.getDefaultInstance(props);
        MimeMessage message = new MimeMessage(session);

        try {
            message.setFrom(new InternetAddress(from));
            InternetAddress[] toAddress = new InternetAddress[to.length];

            // To get the array of addresses
            for( int i = 0; i < to.length; i++ ) {
                toAddress[i] = new InternetAddress(to[i]);
            }

            for( int i = 0; i < toAddress.length; i++) {
                message.addRecipient(Message.RecipientType.TO, toAddress[i]);
            }

            message.setSubject(subject);
            message.setText(body);
            Transport transport = session.getTransport("smtp");
            transport.connect(host, from, pass);
            transport.sendMessage(message, message.getAllRecipients());
            transport.close();
        }
        catch (AddressException ae) {
            ae.printStackTrace();
        }
        catch (MessagingException me) {
            me.printStackTrace();
        }
    }
}

当然，您需要在 catch 块中执行更多操作，而不是像我在上面的示例代码中那样打印堆栈跟踪。 （删除 catch 块以查看 JavaMail API 中的哪些方法调用会引发异常，以便您可以更好地了解如何正确处理它们。）

---

感谢 @jodonnel 以及其他所有回答的人。我给他悬赏是因为他的回答让我得到了大约 95% 的完整答案。

Answer 2

像这样的事情（听起来你只需要更改你的 SMTP 服务器）：

String host = "smtp.gmail.com";
String from = "user name";
Properties props = System.getProperties();
props.put("mail.smtp.host", host);
props.put("mail.smtp.user", from);
props.put("mail.smtp.password", "asdfgh");
props.put("mail.smtp.port", "587"); // 587 is the port number of yahoo mail
props.put("mail.smtp.auth", "true");

Session session = Session.getDefaultInstance(props, null);
MimeMessage message = new MimeMessage(session);
message.setFrom(new InternetAddress(from));

InternetAddress[] to_address = new InternetAddress[to.length];
int i = 0;
// To get the array of addresses
while (to[i] != null) {
    to_address[i] = new InternetAddress(to[i]);
    i++;
}
System.out.println(Message.RecipientType.TO);
i = 0;
while (to_address[i] != null) {

    message.addRecipient(Message.RecipientType.TO, to_address[i]);
    i++;
}
message.setSubject("sending in a group");
message.setText("Welcome to JavaMail");
// alternately, to send HTML mail:
// message.setContent("<p>Welcome to JavaMail</p>", "text/html");
Transport transport = session.getTransport("smtp");
transport.connect("smtp.mail.yahoo.co.in", "user name", "asdfgh");
transport.sendMessage(message, message.getAllRecipients());
transport.close();

Answer 3

上面其他人有很好的答案，但我想在这里补充一下我的经验。我发现，当使用 Gmail 作为我的网络应用程序的出站 SMTP 服务器时，Gmail 只允许我发送大约 10 封左右的邮件，然后再进行反垃圾邮件响应，我必须手动逐步执行该响应才能重新启用 SMTP 访问。我发送的电子邮件不是垃圾邮件，而是用户在我的系统注册时收到的网站“欢迎”电子邮件。所以，YMMV，我不会依赖 Gmail 来构建网络应用程序。如果您代表用户发送电子邮件，例如安装的桌面应用程序（用户输入自己的 Gmail 凭据），则可能没问题。

另外，如果您使用 Spring，这里有一个使用 Gmail 进行出站 SMTP 的工作配置：

<bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
    <property name="defaultEncoding" value="UTF-8"/>
    <property name="host" value="smtp.gmail.com"/>
    <property name="port" value="465"/>
    <property name="username" value="${mail.username}"/>
    <property name="password" value="${mail.password}"/>
    <property name="javaMailProperties">
        <value>
            mail.debug=true
            mail.smtp.auth=true
            mail.smtp.socketFactory.class=java.net.SocketFactory
            mail.smtp.socketFactory.fallback=false
        </value>
    </property>
</bean>

Answer 4

即使这个问题已经结束，我想发布一个计数器解决方案，但现在使用 Simple Java Mail （开源 JavaMail smtp 包装器）：

final Email email = new Email();

String host = "smtp.gmail.com";
Integer port = 587;
String from = "username";
String pass = "password";
String[] to = {"[email protected]"};

email.setFromAddress("", from);
email.setSubject("sending in a group");
for( int i=0; i < to.length; i++ ) {
    email.addRecipient("", to[i], RecipientType.TO);
}
email.setText("Welcome to JavaMail");

new Mailer(host, port, from, pass).sendMail(email);
// you could also still use your mail session instead
new Mailer(session).sendMail(email);

Answer 5

我的完整代码如下运行良好：

package ripon.java.mail;
import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;

public class SendEmail
{
public static void main(String [] args)
{    
    // Sender's email ID needs to be mentioned
     String from = "[email protected]";
     String pass ="test123";
    // Recipient's email ID needs to be mentioned.
   String to = "[email protected]";

   String host = "smtp.gmail.com";

   // Get system properties
   Properties properties = System.getProperties();
   // Setup mail server
   properties.put("mail.smtp.starttls.enable", "true");
   properties.put("mail.smtp.host", host);
   properties.put("mail.smtp.user", from);
   properties.put("mail.smtp.password", pass);
   properties.put("mail.smtp.port", "587");
   properties.put("mail.smtp.auth", "true");

   // Get the default Session object.
   Session session = Session.getDefaultInstance(properties);

   try{
      // Create a default MimeMessage object.
      MimeMessage message = new MimeMessage(session);

      // Set From: header field of the header.
      message.setFrom(new InternetAddress(from));

      // Set To: header field of the header.
      message.addRecipient(Message.RecipientType.TO,
                               new InternetAddress(to));

      // Set Subject: header field
      message.setSubject("This is the Subject Line!");

      // Now set the actual message
      message.setText("This is actual message");

      // Send message
      Transport transport = session.getTransport("smtp");
      transport.connect(host, from, pass);
      transport.sendMessage(message, message.getAllRecipients());
      transport.close();
      System.out.println("Sent message successfully....");
   }catch (MessagingException mex) {
      mex.printStackTrace();
   }
}
}

Answer 6

//set CLASSPATH=%CLASSPATH%;activation.jar;mail.jar
import javax.mail.*;
import javax.mail.internet.*;
import java.util.*;

public class Mail
{
    String  d_email = "[email protected]",
            d_password = "****",
            d_host = "smtp.gmail.com",
            d_port  = "465",
            m_to = "[email protected]",
            m_subject = "Testing",
            m_text = "Hey, this is the testing email using smtp.gmail.com.";
    public static void main(String[] args)
    {
        String[] to={"[email protected]"};
        String[] cc={"[email protected]"};
        String[] bcc={"[email protected]"};
        //This is for google
        Mail.sendMail("[email protected]", "password", "smtp.gmail.com", 
                      "465", "true", "true", 
                      true, "javax.net.ssl.SSLSocketFactory", "false", 
                      to, cc, bcc, 
                      "hi baba don't send virus mails..", 
                      "This is my style...of reply..If u send virus mails..");
    }

    public synchronized static boolean sendMail(
        String userName, String passWord, String host, 
        String port, String starttls, String auth, 
        boolean debug, String socketFactoryClass, String fallback, 
        String[] to, String[] cc, String[] bcc, 
        String subject, String text) 
    {
        Properties props = new Properties();
        //Properties props=System.getProperties();
        props.put("mail.smtp.user", userName);
        props.put("mail.smtp.host", host);
        if(!"".equals(port))
            props.put("mail.smtp.port", port);
        if(!"".equals(starttls))
            props.put("mail.smtp.starttls.enable",starttls);
        props.put("mail.smtp.auth", auth);
        if(debug) {
            props.put("mail.smtp.debug", "true");
        } else {
            props.put("mail.smtp.debug", "false");         
        }
        if(!"".equals(port))
            props.put("mail.smtp.socketFactory.port", port);
        if(!"".equals(socketFactoryClass))
            props.put("mail.smtp.socketFactory.class",socketFactoryClass);
        if(!"".equals(fallback))
            props.put("mail.smtp.socketFactory.fallback", fallback);

        try
        {
            Session session = Session.getDefaultInstance(props, null);
            session.setDebug(debug);
            MimeMessage msg = new MimeMessage(session);
            msg.setText(text);
            msg.setSubject(subject);
            msg.setFrom(new InternetAddress("[email protected]"));
            for(int i=0;i<to.length;i++) {
                msg.addRecipient(Message.RecipientType.TO, 
                                 new InternetAddress(to[i]));
            }
            for(int i=0;i<cc.length;i++) {
                msg.addRecipient(Message.RecipientType.CC, 
                                 new InternetAddress(cc[i]));
            }
            for(int i=0;i<bcc.length;i++) {
                msg.addRecipient(Message.RecipientType.BCC, 
                                 new InternetAddress(bcc[i]));
            }
            msg.saveChanges();
            Transport transport = session.getTransport("smtp");
            transport.connect(host, userName, passWord);
            transport.sendMessage(msg, msg.getAllRecipients());
            transport.close();
            return true;
        }
        catch (Exception mex)
        {
            mex.printStackTrace();
            return false;
        }
    }

}

Answer 7

最低要求：

import java.util.Properties;

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

public class MessageSender {

    public static void sendHardCoded() throws AddressException, MessagingException {
        String to = "[email protected]";
        final String from = "[email protected]";

        Properties properties = new Properties();
        properties.put("mail.smtp.starttls.enable", "true");
        properties.put("mail.smtp.auth", "true");
        properties.put("mail.smtp.host", "smtp.gmail.com");
        properties.put("mail.smtp.port", "587");

        Session session = Session.getInstance(properties,
                new javax.mail.Authenticator() {
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(from, "BeNice");
                    }
                });

        MimeMessage message = new MimeMessage(session);
        message.setFrom(new InternetAddress(from));
        message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
        message.setSubject("Hello");
        message.setText("What's up?");

        Transport.send(message);
    }

}

Answer 8

当您需要在同一JVM中的任何地方设置多个SMTP会话时，已发布的代码解决方案可能会导致问题。

Javamail常见问题解答建议使用

Session.getInstance(properties);

而不是

Session.getDefaultInstance(properties);

使用，因为GetDefault仅使用第一次调用属性。默认实例的所有以后使用将忽略属性更改。

参见 http:///wwwww.oracle.com/technetwork.com/technetwork/technetwork/java/java/java/java/java/java/java/java/java/java/java/java-java/java/java-java/java/java/java-faq--- 135477.html＃getDefaultInstance

Answer 9

增值：

• 主题、消息和显示名称中的编码陷阱
• 仅需要一个神奇属性，现代 Java 邮件库版本
• Session.getInstance() 推荐使用 Session.getDefaultInstance()
• 在同一示例中，
• 附件 ，在 href="https://gsuiteupdates.googleblog.com/2019/12/less-secure-apps-oauth-google-username-password-in Correct.html" rel="nofollow noreferrer">Google 关闭安全性较低的应用：在您的组织中启用 2 因素身份验证 ->打开 2FA ->生成应用程序密码。

    import java.io.File;
    import java.nio.charset.StandardCharsets;
    import java.util.Properties;
    import java.util.logging.Level;
    import java.util.logging.Logger;
    import javax.activation.DataHandler;
    import javax.mail.Message;
    import javax.mail.Session;
    import javax.mail.Transport;
    import javax.mail.internet.InternetAddress;
    import javax.mail.internet.MimeBodyPart;
    import javax.mail.internet.MimeMessage;
    import javax.mail.internet.MimeMultipart;
    import javax.mail.util.ByteArrayDataSource;
    
    public class Gmailer {
      private static final Logger LOGGER = Logger.getLogger(Gmailer.class.getName());
    
      public static void main(String[] args) {
        send();
      }
    
      public static void send() {
        Transport transport = null;
        try {
          String accountEmail = "[email protected]";
          String accountAppPassword = "";
          String displayName = "Display-Name 東";
          String replyTo = "[email protected]";
    
          String to = "[email protected]";
          String cc = "[email protected]";
          String bcc = "[email protected]";
    
          String subject = "Subject 東";
          String message = "<span style='color: red;'>東</span>";
          String type = "html"; // or "plain"
          String mimeTypeWithEncoding = "text/" + type + "; charset=" + StandardCharsets.UTF_8.name();
    
          File attachmentFile = new File("Attachment.pdf");
          // https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types
          String attachmentMimeType = "application/pdf";
          byte[] bytes = ...; // read file to byte array
    
          Properties properties = System.getProperties();
          properties.put("mail.debug", "true");
          // i found that this is the only property necessary for a modern java mail version
          properties.put("mail.smtp.starttls.enable", "true");
          // https://javaee.github.io/javamail/FAQ#getdefaultinstance
          Session session = Session.getInstance(properties);
    
          MimeMessage mimeMessage = new MimeMessage(session);
    
          // probably best to use the account email address, to avoid landing in spam or blacklists
          // not even sure if the server would accept a differing from address
          InternetAddress from = new InternetAddress(accountEmail);
          from.setPersonal(displayName, StandardCharsets.UTF_8.name());
          mimeMessage.setFrom(from);
    
          mimeMessage.setReplyTo(InternetAddress.parse(replyTo));
    
          mimeMessage.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));
          mimeMessage.setRecipients(Message.RecipientType.CC, InternetAddress.parse(cc));
          mimeMessage.setRecipients(Message.RecipientType.BCC, InternetAddress.parse(bcc));
    
          mimeMessage.setSubject(subject, StandardCharsets.UTF_8.name());
    
          MimeMultipart multipart = new MimeMultipart();
    
          MimeBodyPart messagePart = new MimeBodyPart();
          messagePart.setContent(mimeMessage, mimeTypeWithEncoding);
          multipart.addBodyPart(messagePart);
    
          MimeBodyPart attachmentPart = new MimeBodyPart();
          attachmentPart.setDataHandler(new DataHandler(new ByteArrayDataSource(bytes, attachmentMimeType)));
          attachmentPart.setFileName(attachmentFile.getName());
          multipart.addBodyPart(attachmentPart);
    
          mimeMessage.setContent(multipart);
    
          transport = session.getTransport();
          transport.connect("smtp.gmail.com", 587, accountEmail, accountAppPassword);
          transport.sendMessage(mimeMessage, mimeMessage.getAllRecipients());
        }
        catch(Exception e) {
          // I prefer to bubble up exceptions, so the caller has the info that someting went wrong, and gets a chance to handle it.
          // I also prefer not to force the exception in the signature.
          throw e instanceof RuntimeException ? (RuntimeException) e : new RuntimeException(e);
        }
        finally {
          if(transport != null) {
            try {
              transport.close();
            }
            catch(Exception e) {
              LOGGER.log(Level.WARNING, "failed to close java mail transport: " + e);
            }
          }
        }
      }
    }

Answer 10

这是我想发送带有附件的电子邮件时要做的，工作正常。 :)

 public class NewClass {

    public static void main(String[] args) {
        try {
            Properties props = System.getProperties();
            props.put("mail.smtp.starttls.enable", "true");
            props.put("mail.smtp.host", "smtp.gmail.com");
            props.put("mail.smtp.auth", "true");
            props.put("mail.smtp.port", "465"); // smtp port
            Authenticator auth = new Authenticator() {

                @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication("username-gmail", "password-gmail");
                }
            };
            Session session = Session.getDefaultInstance(props, auth);
            MimeMessage msg = new MimeMessage(session);
            msg.setFrom(new InternetAddress("[email protected]"));
            msg.setSubject("Try attachment gmail");
            msg.setRecipient(RecipientType.TO, new InternetAddress("[email protected]"));
            //add atleast simple body
            MimeBodyPart body = new MimeBodyPart();
            body.setText("Try attachment");
            //do attachment
            MimeBodyPart attachMent = new MimeBodyPart();
            FileDataSource dataSource = new FileDataSource(new File("file-sent.txt"));
            attachMent.setDataHandler(new DataHandler(dataSource));
            attachMent.setFileName("file-sent.txt");
            attachMent.setDisposition(MimeBodyPart.ATTACHMENT);
            Multipart multipart = new MimeMultipart();
            multipart.addBodyPart(body);
            multipart.addBodyPart(attachMent);
            msg.setContent(multipart);
            Transport.send(msg);
        } catch (AddressException ex) {
            Logger.getLogger(NewClass.class.getName()).log(Level.SEVERE, null, ex);
        } catch (MessagingException ex) {
            Logger.getLogger(NewClass.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

}

Answer 11

一个简单的方法是配置/启用 POP3 访问的 Gmail 帐户。这将允许您通过 gmail 服务器通过普通 SMTP 发送出去。

然后您只需通过 smtp.gmail.com（端口 587）发送

Answer 12

嗨，尝试此代码。

package my.test.service;

import java.util.Properties;

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

public class Sample {
    public static void main(String args[]) {
        final String SMTP_HOST = "smtp.gmail.com";
        final String SMTP_PORT = "587";
        final String GMAIL_USERNAME = "[email protected]";
        final String GMAIL_PASSWORD = "xxxxxxxxxx";

        System.out.println("Process Started");

        Properties prop = System.getProperties();
        prop.setProperty("mail.smtp.starttls.enable", "true");
        prop.setProperty("mail.smtp.host", SMTP_HOST);
        prop.setProperty("mail.smtp.user", GMAIL_USERNAME);
        prop.setProperty("mail.smtp.password", GMAIL_PASSWORD);
        prop.setProperty("mail.smtp.port", SMTP_PORT);
        prop.setProperty("mail.smtp.auth", "true");
        System.out.println("Props : " + prop);

        Session session = Session.getInstance(prop, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(GMAIL_USERNAME,
                        GMAIL_PASSWORD);
            }
        });

        System.out.println("Got Session : " + session);

        MimeMessage message = new MimeMessage(session);
        try {
            System.out.println("before sending");
            message.setFrom(new InternetAddress(GMAIL_USERNAME));
            message.addRecipients(Message.RecipientType.TO,
                    InternetAddress.parse(GMAIL_USERNAME));
            message.setSubject("My First Email Attempt from Java");
            message.setText("Hi, This mail came from Java Application.");
            message.setRecipients(Message.RecipientType.TO,
                    InternetAddress.parse(GMAIL_USERNAME));
            Transport transport = session.getTransport("smtp");
            System.out.println("Got Transport" + transport);
            transport.connect(SMTP_HOST, GMAIL_USERNAME, GMAIL_PASSWORD);
            transport.sendMessage(message, message.getAllRecipients());
            System.out.println("message Object : " + message);
            System.out.println("Email Sent Successfully");
        } catch (AddressException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (MessagingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Answer 13

这是一个易于使用的类，用于使用 Gmail 发送电子邮件。您需要有 JavaMail 库 添加到您的构建路径 或仅使用 Maven。

import java.util.Properties;

import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

public class GmailSender
{
    private static String protocol = "smtp";

    private String username;
    private String password;

    private Session session;
    private Message message;
    private Multipart multipart;

    public GmailSender()
    {
        this.multipart = new MimeMultipart();
    }

    public void setSender(String username, String password)
    {
        this.username = username;
        this.password = password;

        this.session = getSession();
        this.message = new MimeMessage(session);
    }

    public void addRecipient(String recipient) throws AddressException, MessagingException
    {
        message.addRecipient(Message.RecipientType.TO, new InternetAddress(recipient));
    }

    public void setSubject(String subject) throws MessagingException
    {
        message.setSubject(subject);
    }

    public void setBody(String body) throws MessagingException
    {
        BodyPart messageBodyPart = new MimeBodyPart();
        messageBodyPart.setText(body);
        multipart.addBodyPart(messageBodyPart);

        message.setContent(multipart);
    }

    public void send() throws MessagingException
    {
        Transport transport = session.getTransport(protocol);
        transport.connect(username, password);
        transport.sendMessage(message, message.getAllRecipients());

        transport.close();
    }

    public void addAttachment(String filePath) throws MessagingException
    {
        BodyPart messageBodyPart = getFileBodyPart(filePath);
        multipart.addBodyPart(messageBodyPart);

        message.setContent(multipart);
    }

    private BodyPart getFileBodyPart(String filePath) throws MessagingException
    {
        BodyPart messageBodyPart = new MimeBodyPart();
        DataSource dataSource = new FileDataSource(filePath);
        messageBodyPart.setDataHandler(new DataHandler(dataSource));
        messageBodyPart.setFileName(filePath);

        return messageBodyPart;
    }

    private Session getSession()
    {
        Properties properties = getMailServerProperties();
        Session session = Session.getDefaultInstance(properties);

        return session;
    }

    private Properties getMailServerProperties()
    {
        Properties properties = System.getProperties();
        properties.put("mail.smtp.starttls.enable", "true");
        properties.put("mail.smtp.host", protocol + ".gmail.com");
        properties.put("mail.smtp.user", username);
        properties.put("mail.smtp.password", password);
        properties.put("mail.smtp.port", "587");
        properties.put("mail.smtp.auth", "true");

        return properties;
    }
}

用法示例：

GmailSender sender = new GmailSender();
sender.setSender("[email protected]", "mypassword");
sender.addRecipient("[email protected]");
sender.setSubject("The subject");
sender.setBody("The body");
sender.addAttachment("TestFile.txt");
sender.send();

Answer 14

如果您想将 Outlook 与 Javamail API 一起使用，请用作

smtp-mail.outlook.com

主机以获取更多完整的工作代码查看此答案。