Java 传输。发送（消息）在以下代码中不起作用。。netbeans在运行部分卡住了。它没有'；4.别再往前走了。。它永远挂在那里

我试着用Java编写一个发送电子邮件的代码。但是这个代码不起作用。当代码被执行时，它会在transport.send（message）处卡住。它永远卡在那里。另外，我不确定代码的其余部分是否正确

  //first from, to, subject, & text values are set
    public class SendMail {
    private String from;
    private String to;
    private String subject;
    private String text;


    public SendMail(String from, String to, String subject, String text){
        this.from = from;
        this.to = to;
        this.subject = subject;
        this.text = text;
    }

    //send method is called in the end 
    public void send(){

        Properties props = new Properties();
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.port", "465");

        Session mailSession = Session.getDefaultInstance(props);
        Message simpleMessage = new MimeMessage(mailSession);

        InternetAddress fromAddress = null;
        InternetAddress toAddress = null;
        try {
            fromAddress = new InternetAddress(from);
            toAddress = new InternetAddress(to);
        } catch (AddressException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        try {
            simpleMessage.setFrom(fromAddress);
            simpleMessage.setRecipient(RecipientType.TO, toAddress);
            simpleMessage.setSubject(subject);
                    simpleMessage.setText(text);
            Transport.send(simpleMessage);  // this is where code hangs     
        } catch (MessagingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }       
    }
}

请试试这个

    public class SMTPDemo {

  public static void main(String args[]) throws IOException,
      UnknownHostException {
    String msgFile = "file.txt";
    String from = "java2s@java2s.com";
    String to = "yourEmail@yourServer.com";
    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;
    }
  }
}

公共类SMTPDemo{
公共静态void main（字符串args[]）引发IOException，
未知后异常{
字符串msgFile=“file.txt”；
字符串from=”java2s@java2s.com";
字符串to=”yourEmail@yourServer.com";
字符串mailHost=“yourHost”；
SMTP邮件=新SMTP（邮件主机）；
如果（邮件！=null）{
if（mail.send（新文件读取器（msgFile）、from、to））{
System.out.println（“邮件已发送”）；
}否则{
System.out.println（“连接到SMTP服务器失败！”）；
}
}
System.out.println（“完成”）；
}
静态类SMTP{
专用最终静态int SMTP_端口=25；
邮件主机地址；
本地主机地址；
缓冲读取器；
打印输出；
公共SMTP（字符串主机）引发UnknownHostException{
mailHost=InetAddress.getByName（主机）；
localhost=InetAddress.getLocalHost（）；
System.out.println（“mailhost=“+mailhost”）；
System.out.println（“localhost=“+localhost”）；
System.out.println（“SMTP构造函数完成\n”）；
}
公共布尔发送（FileReader msgFileReader、字符串从、字符串到）
抛出IOException{
承插短管；
InputStream酒店；
输出流输出；
缓冲阅读味精；
msg=新的BufferedReader（msgFileReader）；
smtpPipe=新套接字（邮件主机、SMTP_端口）；
如果（smtpPipe==null）{
返回false；
}
inn=smtpPipe.getInputStream（）；
outt=smtpPipe.getOutputStream（）；
in=新的BufferedReader（新的InputStreamReader（inn））；
out=新的PrintWriter（新的OutputStreamWriter（outt）），true；
如果（inn==null | | outt==null）{
System.out.println（“未能将流打开到套接字”）；
返回false；
}
字符串initialID=in.readLine（）；
System.out.println（initialID）；
System.out.println（“HELO”+localhost.getHostName（））；
out.println（“HELO”+localhost.getHostName（））；
字符串welcome=in.readLine（）；
System.out.println（欢迎）；
System.out.println（“邮件发件人：”）；
out.println（“邮件发件人：”）；
字符串senderOK=in.readLine（）；
系统输出打印LN（senderOK）；
System.out.println（“RCPT TO:”）；
out.println（“RCPT TO:”）；
字符串recipientOK=in.readLine（）；
System.out.println（recipientOK）；
系统输出打印项次（“数据”）；
out.println（“数据”）；
弦线；
而（（line=msg.readLine（））！=null）{
out.println（行）；
}
系统输出打印项次（“.”）；
out.println（“.”）；
字符串acceptedOK=in.readLine（）；
System.out.println（acceptedOK）；
System.out.println（“退出”）；
out.println（“退出”）；
返回true；
}
}
}

用Session.getInstance替换Session.getDefaultInstance

---

如果这不能解决问题，请阅读JavaMail常见问题解答，其中有调试提示。

我遇到了完全相同的问题，其他人报告了间歇性故障。原因是Transport.send with SMTP有两个无限超时，这可能会导致进程挂起

来自SUN文档：

mail.smtp.connectiontimeout int套接字连接超时值（毫秒）默认值为无限超时。

mail.smtp.timeout int套接字I/O超时值（毫秒）默认值为无限超时。

若要永远不“挂起”，可以显式设置：

来自SUN：属性始终设置为字符串；类型列描述如何解释字符串。例如，使用

    props.put("mail.smtp.port", "888");

请注意，如果您使用“smtps”协议通过SSL访问SMTP，则所有属性都将命名为“mail.smtps.*”

因此，如果您设置了两个超时，您应该得到一个“MessaginException”，您可以通过try/catch处理它，而不是让进程挂起

假设您正在使用smtp，请添加以下内容，其中t1和t2是您的超时值，单位为毫秒：

    props.put("mail.smtp.connectiontimeout", "t1");
    props.put("mail.smtp.timeout", "t2");

当然，这不会解决超时的根本原因，但它会让您优雅地处理问题

感谢西格弗里德·戈施尔在

---

PS：我遇到的问题的根本原因似乎与我旅行时使用的网络连接有关。显然，该连接导致了SMTP超时，这是我与任何其他连接都没有的

也有同样的问题。您必须关闭挡块中的运输。代码冻结的原因是，除非手动关闭smtp服务器连接，否则客户端的smtp服务器连接永远不会关闭

    try {
        simpleMessage.setFrom(fromAddress);
        simpleMessage.setRecipient(RecipientType.TO, toAddress);
        simpleMessage.setSubject(subject);
                simpleMessage.setText(text);
        Transport.send(simpleMessage);  // this is where code hangs     
    } catch (MessagingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        Transport.close()
    } 

但是确保javamail正确退出的最有效方法是将javamail逻辑捆绑到一个try块中，并在finally块中关闭传输。试试这个。 [编辑]在收到上述代码不起作用的警报后，此处是正确编译的代码

import java.util.Properties;

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

//first from, to, subject, & text values are set

public class SendMail {
    private String from;
    private String to;
    private String subject;
    private String text;

    public SendMail(String from, String to, String subject, String text) {
            this.from = from;
            this.to = to;
        this.subject = subject;
            this.text = text;
    }

    // send method is called in the end
    public void send() throws MessagingException {

        Properties props = new Properties();
    props.put("mail.transport.protocol", "smtp");
    props.put("mail.smtp.host", "localhost");
    props.put("mail.smtp.auth", "false");// set to false for no username
    props.put("mail.debug", "false");
    props.put("mail.smtp.port", "25");

    Session session = Session.getDefaultInstance(props);

    InternetAddress fromAddress = null;
    InternetAddress toAddress = null;
    Transport transport = session.getTransport("smtp");
    transport.connect();
    try {
        Message simpleMessage = new MimeMessage(session);
        fromAddress = new InternetAddress(from);
        toAddress = new InternetAddress(to);
        simpleMessage.setFrom(fromAddress);
        simpleMessage.setRecipient(RecipientType.TO, toAddress);
        simpleMessage.setSubject(subject);
        simpleMessage.setText(text);
        transport.sendMessage(simpleMessage,
                simpleMessage.getAllRecipients());
    } catch (MessagingException e) {
        e.printStackTrace();
    } finally {
        transport.close();
    }
     }
 }

禁用所有防病毒程序

禁用防火墙

然后试一试，如果你成功了，进一步调查以找到罪犯

---

在我的例子中，它是防病毒的，我必须对

SMTP

上的出站邮件设置一个例外才能成功发送邮件。

当您声明

Transport.send（）

时，它将不起作用，请使用此选项而不是

transport.sendMessage（message，message.getAllRecipients（））

并声明一个

javax.mail.Transport=session.getTransport（“smtp”）对象，如代码中所示

       javax.mail.Transport transport = session.getTransport("smtp");
 transport.sendMessage(message,message.getAllRecipients());

然后下面的代码将如下所示谢谢，希望这将完美地工作

package org.java.vamsi;
//import javax.activation.*;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Properties;
//import java.io.*;
//import javax.mail.internet.*;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.mail.Message.RecipientType;
//import com.sun.corba.se.impl.protocol.giopmsgheaders.Message;

//import java.io.*;
//import java.util.*;
//import javax.servlet.*;
//import javax.servlet.http.*;
//import javax.mail.*;
//import javax.mail.internet.*;
//import javax.activation.*;



//import sun.rmi.transport.Transport;

public class SendEmail extends HttpServlet {
    private static final long serialVersionUID = 1L;

        public void doGet(HttpServletRequest request,
                HttpServletResponse response)
        throws ServletException, IOException
{
  // Recipient's email ID needs to be mentioned.
  String to = "mysore.vamsikrishna@gmail.com";

  // Sender's email ID needs to be mentioned
  String from = "mysore.vamsikrishna007@gmail.com";

  // Assuming you are sending email from localhost
  String host = "localhost";

  // Get system properties
  Properties properties = System.getProperties();

  // Setup mail server
  properties.setProperty("mail.smtp.host", host);

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

  // Set response content type
  response.setContentType("text/html");
  PrintWriter out = response.getWriter();

  try{
      javax.mail.Transport transport = session.getTransport("smtp");
     // 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(RecipientType.TO,
                              new InternetAddress(to));//as we are importing the "javax.mail.Message.RecipientType"
     //we have to not set the type as this 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.sendMessage(message,
             message.getAllRecipients());
     String title = "Send Email";
     String res = "Sent message successfully....";
     String docType =
     "<!doctype html public \"-//w3c//dtd html 4.0 " +
     "transitional//en\">\n";
     out.println(docType +
     "<html>\n" +
     "<head><title>" + title + "</title></head>\n" +
     "<body bgcolor=\"#f0f0f0\">\n" +
     "<h1 align=\"center\">" + title + "</h1>\n" +
     "<p align=\"center\">" + res + "</p>\n" +
     "</body></html>");
  }catch (MessagingException mex) {
     mex.printStackTrace();
  }
}           
    }

package org.java.vamsi；
//导入javax.a
     <dependency>
        <groupId>javax.mail</groupId>
        <artifactId>javax.mail-api</artifactId>
        <version>1.6.1</version>
    </dependency>
    <dependency>
        <groupId>com.sun.mail</groupId>
        <artifactId>javax.mail</artifactId>
        <version>1.5.3</version>
    </dependency>

     <dependency>
        <groupId>javax.mail</groupId>
        <artifactId>javax.mail-api</artifactId>
        <version>1.5.3</version>
    </dependency>
    <dependency>
        <groupId>com.sun.mail</groupId>
        <artifactId>javax.mail</artifactId>
        <version>1.5.3</version>
    </dependency>