我在发送电子邮件时遇到问题。

javax.mail.SendFailedException: Sending failed;
  nested exception is: 
    javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25;
  nested exception is: 
    java.net.ConnectException: Connection refused: connect
    at javax.mail.Transport.send0(Transport.java:219)
    at javax.mail.Transport.send(Transport.java:81)
    at org.apache.jsp.online_005fScheme_005fSend_005fMail_jsp.sendMail(online_005fScheme_005fSend_005fMail_jsp.java:116)
    at org.apache.jsp.online_005fScheme_005fSend_005fMail_jsp._jspService(online_005fScheme_005fSend_005fMail_jsp.java:416)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:308)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:259)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:879)
    at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
    at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
    at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
    at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
    at java.lang.Thread.run(Thread.java:619)

我使用下面的代码片段。

Properties props = new Properties();
     props.put("mail.smtp.host", "10.101.3.229");

电子邮件发送程序在 tomcat 5 上运行。有时它工作正常，有时它会导致上述异常。一旦它开始导致上述异常，它在每次访问时都会产生相同的结果。但是只要我重新启动 tomcat 服务器，它就会再次正常工作。

所以我找不到原因。因为有时同样工作正常，有时结果高于异常。

谁能帮我解决这个问题。

最佳答案

package sn;
import java.util.Date;
import java.util.Properties;
import javax.mail.Authenticator;
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 SendEmail {
  public static void main(String[] args) {
    final String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory";
 // Get a Properties object
    Properties props = System.getProperties();
    props.setProperty("mail.smtp.host", "smtp.gmail.com");
    props.setProperty("mail.smtp.socketFactory.class", SSL_FACTORY);
    props.setProperty("mail.smtp.socketFactory.fallback", "false");
    props.setProperty("mail.smtp.port", "465");
    props.setProperty("mail.smtp.socketFactory.port", "465");
    props.put("mail.smtp.auth", "true");
    props.put("mail.debug", "true");
    props.put("mail.store.protocol", "pop3");
    props.put("mail.transport.protocol", "smtp");
    final String username = "xxxx@gmail.com";//
    final String password = "0000000";
    try{
      Session session = Session.getDefaultInstance(props, 
                          new Authenticator(){
                             protected PasswordAuthentication getPasswordAuthentication() {
                                return new PasswordAuthentication(username, password);
                             }});

   // -- Create a new message --
      Message msg = new MimeMessage(session);

   // -- Set the FROM and TO fields --
      msg.setFrom(new InternetAddress("xxxx@gmail.com"));
      msg.setRecipients(Message.RecipientType.TO, 
                        InternetAddress.parse("user120@example.com",false));
      msg.setSubject("Hello");
      msg.setText("How are you");
      msg.setSentDate(new Date());
      Transport.send(msg);
      System.out.println("Message sent.");
    }catch (MessagingException e){ 
      System.out.println("Erreur d'envoi, cause: " + e);
    }
  }
}

关于javax.mail.MessagingException : Could not connect to SMTP host: localhost, 端口:25，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19493904/