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

How can I send an email by Java application using GMail, Yahoo, or Hotmail?

提问by Bill the Lizard

Is it possible to send an email from my Java application using a GMail account? I have configured my company mail server with Java app to send email, but that's not going to cut it when I distribute the application. Answers with any of using Hotmail, Yahoo or GMail are acceptable.

是否可以使用 GMail 帐户从我的 Java 应用程序发送电子邮件？我已经用 Java 应用程序配置了我的公司邮件服务器来发送电子邮件，但是当我分发应用程序时不会削减它。任何使用 Hotmail、Yahoo 或 GMail 的答案都是可以接受的。

采纳答案by Bill the Lizard

First download the JavaMail APIand make sure the relevant jar files are in your classpath.

首先下载JavaMail API并确保相关的 jar 文件在您的类路径中。

Here's a full working example using GMail.

这是一个使用 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();
        }
    }
}

Naturally, you'll want to do more in the catchblocks than print the stack trace as I did in the example code above. (Remove the catchblocks to see which method calls from the JavaMail API throw exceptions so you can better see how to properly handle them.)

自然，您会希望在catch块中做更多的事情，而不是像我在上面的示例代码中那样打印堆栈跟踪。（删除这些catch块以查看来自 JavaMail API 的哪些方法调用抛出异常，以便您可以更好地了解如何正确处理它们。）

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---

Thanks to @jodonneland everyone else who answered. I'm giving him a bounty because his answer led me about 95% of the way to a complete answer.

感谢@jodonnel和其他所有回答的人。我给了他一个赏金，因为他的回答引导我完成了大约 95% 的回答。

回答by Ryan Farley

An easy route would be to have the gmail account configured/enabled for POP3 access. This would allow you to send out via normal SMTP through the gmail servers.

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

Then you'd just send through smtp.gmail.com (on port 587)

然后您只需通过 smtp.gmail.com（在端口 587 上）发送

回答by jodonnell

Something like this (sounds like you just need to change your SMTP server):

像这样（听起来您只需要更改您的 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();

回答by user109771

Even though this question is closed, I'd like to post a counter solution, but now using Simple Java Mail(Open Source JavaMail smtp wrapper):

即使此问题已关闭，我还是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);

回答by Ifnu

This is what I do when i want to send email with attachment, work fine. :)

当我想发送带有附件的电子邮件时，这就是我所做的，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);
        }
    }

}

回答by Jason Thrasher

Other people have good answers above, but I wanted to add a note on my experience here. I've found that when using Gmail as an outbound SMTP server for my webapp, Gmail only lets me send ~10 or so messages before responding with an anti-spam response that I have to manually step through to re-enable SMTP access. The emails I was sending were not spam, but were website "welcome" emails when users registered with my system. So, YMMV, and I wouldn't rely on Gmail for a production webapp. If you're sending email on a user's behalf, like an installed desktop app (where the user enters their own Gmail credentials), you may be okay.

其他人在上面有很好的答案，但我想在这里添加一个关于我的经验的注释。我发现当使用 Gmail 作为我的 web 应用程序的出站 SMTP 服务器时，Gmail 只允许我发送大约 10 封邮件，然后我必须手动通过反垃圾邮件响应来重新启用 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中注册时收到的网站“欢迎”电子邮件。所以，YMMV，我不会依赖 Gmail 来生产 web 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（用户在其中输入自己的 Gmail 凭据），则可能没问题。

Also, if you're using Spring, here's a working config to use Gmail for outbound SMTP:

此外，如果您使用的是 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>

回答by vishnu

//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;
        }
    }

}

回答by Ripon Al Wasim

My complete code as below is working well:

我的完整代码如下所示运行良好：

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();
   }
}
}

回答by Bryan

The posted code solutions may cause problems when you need to set up multiple SMTP sessions anywhere within the same JVM.

当您需要在同一个 JVM 中的任何位置设置多个 SMTP 会话时，发布的代码解决方案可能会导致问题。

The JavaMail FAQ recommends using

JavaMail FAQ 推荐使用

Session.getInstance(properties);

instead of

代替

Session.getDefaultInstance(properties);

because the getDefault will only use the properties given the first time it is invoked. All later uses of the default instance will ignore property changes.

因为 getDefault 将只使用第一次调用时给出的属性。默认实例的所有后续使用都将忽略属性更改。

See http://www.oracle.com/technetwork/java/faq-135477.html#getdefaultinstance

请参阅http://www.oracle.com/technetwork/java/faq-135477.html#getdefaultinstance

回答by Pyare

Hi try this code....

嗨试试这个代码....

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();
        }
    }
}