javax.mail.MessagingException:无法连接到SMTP主机:localhost,port:25

Question

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snipet.

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

电子邮件发送程序正在tomcat 5上运行.有时它工作正常,有时它会导致异常.一旦它产生上述异常,它就会在每次访问时产生相同的结果.但是一旦我重新启动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,有时会导致异常.

任何人都可以帮我解决这个问题.

Answer 1

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);}
  }

}

Answer 2

从您的异常中可以清楚地看出，它正在尝试连接localhost而不是连接10.101.3.229

异常片段：Could not connect to SMTP host: localhost, port: 25;

1.) 请检查是否有任何 null 检查将 localhost 设置为默认值

2.) 重新启动后，如果工作正常，则意味着仅在第一次运行时，才会从“属性”中获取正确的值，并且从下一次运行开始，该值将设置为默认值。因此，将属性对象保留为单例对象，并在整个项目中使用它