将邮件发送到Gmail帐户

我正在从我的Java应用程序向Gmail帐户发送邮件。 我使用过Java Mail API并且运行正常。 但是可以在不使用java中的邮件API的情况下发送电子邮件吗？

我的意思是只使用套接字：

public class Main { public static void main(String[] args) throws Exception { String host = "smtp.gmail.com"; int port = 465; String from = "[e-mail]"; String toAddr = "[e-mail]"; Socket servSocket = new Socket(host, port); DataOutputStream os = new DataOutputStream(servSocket.getOutputStream()); DataInputStream is = new DataInputStream(servSocket.getInputStream()); if (servSocket != null && os != null && is != null) { os.writeBytes("HELO\r\n"); os.writeBytes("MAIL From:" + from + " \r\n"); os.writeBytes("RCPT To:" + toAddr + "\r\n"); os.writeBytes("DATA\r\n"); os.writeBytes("X-Mailer: Java\r\n"); os.writeBytes("DATE: " + DateFormat.getDateInstance(DateFormat.FULL, Locale.US).format(new Date()) + "\r\n"); os.writeBytes("From:" + from + "\r\n"); os.writeBytes("To:" + toAddr + "\r\n"); } os.writeBytes("Subject:\r\n"); os.writeBytes("body\r\n"); os.writeBytes("\r\n.\r\n"); os.writeBytes("QUIT\r\n"); String responseline; while ((responseline = is.readUTF()) != null) { if (responseline.indexOf("Ok") != -1) break; } } } 

但它不起作用，它不发送邮件。 谁能告诉我可能是什么问题？

Answer 1

这是一个很好的例子：

 public class SMTPDemo { public static void main(String args[]) throws IOException, UnknownHostException { String msgFile = "file.txt"; String from = "[e-mail]"; String to = "[e-mail]"; String mailHost = "yourHost"; SMTP mail = new SMTP(mailHost); if (mail != null) { if (mail.send(new FileReader(msgFile), from, to)) { System.out.println("Mail sent."); } else { System.out.println("Connect to SMTP server failed!"); } } System.out.println("Done."); } static class SMTP { private final static int SMTP_PORT = 25; InetAddress mailHost; InetAddress localhost; BufferedReader in; PrintWriter out; public SMTP(String host) throws UnknownHostException { mailHost = InetAddress.getByName(host); localhost = InetAddress.getLocalHost(); System.out.println("mailhost = " + mailHost); System.out.println("localhost= " + localhost); System.out.println("SMTP constructor done\n"); } public boolean send(FileReader msgFileReader, String from, String to) throws IOException { Socket smtpPipe; InputStream inn; OutputStream outt; BufferedReader msg; msg = new BufferedReader(msgFileReader); smtpPipe = new Socket(mailHost, SMTP_PORT); if (smtpPipe == null) { return false; } inn = smtpPipe.getInputStream(); outt = smtpPipe.getOutputStream(); in = new BufferedReader(new InputStreamReader(inn)); out = new PrintWriter(new OutputStreamWriter(outt), true); if (inn == null || outt == null) { System.out.println("Failed to open streams to socket."); return false; } String initialID = in.readLine(); System.out.println(initialID); System.out.println("HELO " + localhost.getHostName()); out.println("HELO " + localhost.getHostName()); String welcome = in.readLine(); System.out.println(welcome); System.out.println("MAIL From:<" + from + ">"); out.println("MAIL From:<" + from + ">"); String senderOK = in.readLine(); System.out.println(senderOK); System.out.println("RCPT TO:<" + to + ">"); out.println("RCPT TO:<" + to + ">"); String recipientOK = in.readLine(); System.out.println(recipientOK); System.out.println("DATA"); out.println("DATA"); String line; while ((line = msg.readLine()) != null) { out.println(line); } System.out.println("."); out.println("."); String acceptedOK = in.readLine(); System.out.println(acceptedOK); System.out.println("QUIT"); out.println("QUIT"); return true; } } } 

– > http://www.java2s.com/Code/Java/Network-Protocol/SendingMailUsingSockets.htm

Answer 2

如果您有动态IP，则可能无法向Googlemail发送邮件。

Answer 3

GMail不允许非安全邮件传输。 您需要在实现中建立SSL / TLS连接。

Answer 4

默认情况下，Google仅允许加密连接。 在我看来，这实际上是一件好事。

但是，如果您必须以纯文本forms发送邮件，则可以在设置下的帐户页面上启用它。

Answer 5

要使用安全连接，请使用SSLSocket而不是Socket，如下所示：

 SSLSocket socket = (SSLSocket) ((SSLSocketFactory) SSLSocketFactory.getDefault()).createSocket(InetAddress.getByName("smtp.gmail.com"), 465);