如何修复“java.net.ConnectException：连接被拒绝：连接”

Question

我正在尝试通过我的网站（JSF 网站）发送电子邮件，该网站部署在 apache 服务器上，但我不断收到“连接被拒绝：连接”消息，但是如果我直接从 NetBeans 运行 Java 应用程序中的代码，则代码可以完美运行。抱歉，如果我在帖子中犯了一些错误，你可以说这是我第一次发帖。:)

    public void sendReplicationCheckResult() {

    String to = "[e-mail]";

    // Sender's email ID needs to be mentioned

    String from = "[e-mail]";

    // Assuming you are sending email from localhost

    String host = "192.168.52.95";

    // Get system properties

    Properties properties = System.getProperties();

    // Setup mail server

    properties.setProperty("mail.smtp.host", host);

    properties.put("mail.smtp.auth", "false");

    properties.setProperty("mail.smtp.port", "25");

    // 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("Replication Check Results");

        // Create the message part 

        BodyPart messageBodyPart = new MimeBodyPart();

        messageBodyPart.setContent(message, "text/html");

        // Create a multipart message

        Multipart multipart = new MimeMultipart();

        // Set text message part

    multipart.addBodyPart(messageBodyPart);

        // Part two is attachment

        messageBodyPart = new MimeBodyPart();

        String filename = "C:\\Temp\\ReplicationCheck.pdf";

        DataSource source = new FileDataSource(filename);

        messageBodyPart.setDataHandler(new DataHandler(source));

        messageBodyPart.setFileName(filename);

        multipart.addBodyPart(messageBodyPart);

Answer 1

192.168.52.95是LAN地址。虽然在您的开发环境中可能有一个邮件服务器在等待，但在您的服务器环境中没有任何东西192.168.52.95。您可能想从属性文件中读取主机，这样您就可以在不同的环境中使用不同的主机。

Answer 2

我能够使用以下代码解决该问题。我的朋友告诉我，java部署在apache上后需要有效的用户名和密码才能连接到smtp服务器，所以我添加了它们，但在我使用sslsocket连接非正常套接字后我的问题解决了。(t.connect(new Socket(host, 25));) //旧方式 //新代码使用 (t.connect(new SSLSocket(SMTP_SERVER, 25))。private static final String SMTP_SERVER = "smtp server";private static final String USERNAME = "username";private static final String PASSWORD = "password";private static final String EMAIL_FROM = "email from";private static final String EMAIL_TO = "email to";private static final String EMAIL_TO_CC = "cc";private static final String EMAIL_SUBJECT = "Subject";public void sendReplicationCheckResult() {    // Get system properties    Properties properties = System.getProperties();    // Setup mail server    properties.setProperty("mail.transport.protocol", "smtp");    properties.setProperty("mail.smtp.host", SMTP_SERVER);    properties.setProperty("mail.smtp.port", "25");    properties.put("mail.smtp.starttls.enable", "true");    properties.put("mail.smtp.auth", "false");    // 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(EMAIL_FROM));        // Set To: header field of the header.        message.addRecipient(Message.RecipientType.TO, new InternetAddress(EMAIL_TO));        // Set Subject: header field        message.setSubject(EMAIL_SUBJECT);        // Create the message part         BodyPart messageBodyPart = new MimeBodyPart();        // Fill the message//            messageBodyPart.setText("This is message body");        // Create a multipart message        Multipart multipart = new MimeMultipart();        // Set text message part //multipart.addBodyPart(messageBodyPart);        // Part two is attachment        messageBodyPart = new MimeBodyPart();        String filename = "File Path";        DataSource source = new FileDataSource(filename);        messageBodyPart.setDataHandler(new DataHandler(source));        messageBodyPart.setFileName("File Name");        multipart.addBodyPart(messageBodyPart);        // Send the complete message parts        message.setContent(multipart);        // Send message        SMTPTransport t = (SMTPTransport) session.getTransport("smtp");        // connect        t.connect(new SSLSocket(SMTP_SERVER, 25) {            @Override            public String[] getSupportedCipherSuites() {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public String[] getEnabledCipherSuites() {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public void setEnabledCipherSuites(String[] strings) {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public String[] getSupportedProtocols() {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public String[] getEnabledProtocols() {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public void setEnabledProtocols(String[] strings) {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public SSLSession getSession() {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public void addHandshakeCompletedListener(HandshakeCompletedListener hl) {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public void removeHandshakeCompletedListener(HandshakeCompletedListener hl) {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public void startHandshake() throws IOException {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public void setUseClientMode(boolean bln) {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public boolean getUseClientMode() {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public void setNeedClientAuth(boolean bln) {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public boolean getNeedClientAuth() {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public void setWantClientAuth(boolean bln) {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public boolean getWantClientAuth() {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public void setEnableSessionCreation(boolean bln) {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }            @Override            public boolean getEnableSessionCreation() {                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.            }        });        // send        t.sendMessage(message, message.getAllRecipients());        System.out.println("Response: " + t.toString());        t.close();        FacesContext.getCurrentInstance().addMessage(null, new FacesMessage(null, "Email was sent Successfully"));    } catch (IOException ex) {        Logger.getLogger(SendEmail.class.getName()).log(Level.SEVERE, null, ex);        FacesContext.getCurrentInstance().addMessage(null, new FacesMessage(null, ex.getLocalizedMessage()));    } catch (MessagingException ex) {        FacesContext.getCurrentInstance().addMessage(null, new FacesMessage(null, ex.getLocalizedMessage()));        Logger.getLogger(SendEmail.class.getName()).log(Level.SEVERE, null, ex);    }}