How To Transportation Electronic Mail From Coffee Programme Amongst Example

Sending Email from Java plan is a mutual requirement. It doesn't affair whether y'all are working on center Java application, spider web application or enterprise Java EE application, y'all may demand to ship electronic mail to warning back upwards personal alongside errors, or simply ship electronic mail to users on registration, password reset or quest them to confirm their electronic mail afterwards registration. There are many such scenarios, where y'all demand mightiness to ship emails from Java program. In mature applications, y'all already convey a module or library dealing alongside all manful someone monarch of electronic mail functionality together with issues e.g. mightiness to ship attachments, images, including signatures together with other rich text formatting on emails, but if y'all convey to code something from scratch thence Java's Mail API is perfect place.

In this article, nosotros volition larn how to ship emails from Java application using postal service API ( javax.mail ) . Before writing code, y'all must know roughly electronic mail basics e.g. y'all demand a SMTP (Simple Mail Transfer Protocol) server.

If y'all are running your Java application inwards Linux, thence y'all should know that SMTP daemon past times default nous on port 25. You tin job whatever postal service server to ship emails from Java, including world electronic mail servers similar GMail, Yahoo or whatever other provider, all y'all demand is their SMTP server details e.g. hostname, port, connecter parameters etc.

You tin too job SSL, TLS to securely connect together with ship emails, but inwards this representative nosotros convey kept it uncomplicated together with simply focusing on minimum logic to ship postal service from Java application.

In farther articles, nosotros volition larn how to ship postal service using attachments, how to ship HTML formatted email, how to attach images inwards emails, how to job SSL authentication to connect GMail Server together with ship emails etc. For now, let's empathise this uncomplicated representative of Java Mail API.

Java Code Example to Send Email

In gild to ship electronic mail from Java plan y'all demand Java Mail API together with Java Activation Framework (JAF), exactly y'all demand mail-1.4.5.jar, smtp-1.4.4.jar, together with activation-1.1.jar. You demand to download these JAR files together with include them inwards your Classpath to run this program. Alternatively y'all tin job Maven for managing dependencies together with tin include all dependencies there. Once y'all convey these JAR files covered, simply follow below steps to exercise together with ship text electronic mail from Java.

1. Create Session object past times calling Session.getDefaultInstance(properties), where properties contains all of import properties e.g. hostname of SMTP server. 
2. Create MimeMessage object past times passing Session obtained inwards previous steps. nosotros convey to laid dissimilar properties inwards this object such equally recipient electronic mail address, subject, electronic mail body, attachments etc.
3. Use javax.mail.Transport to ship the electronic mail message past times calling static method send(email), where electronic mail tin live MimeMessage.

Number of properties y'all transcend to exercise session differs based on the type of SMTP server, for representative if SMTP server doesn't require whatever authentication y'all tin exercise the Session object alongside simply i holding e.g. smtp.mail.host, no demand to furnish port fifty-fifty because it nous on default port 25. On the other mitt if y'all are connecting to a SMTP server which requires TLS or SSL authentication, e.g. GMail's SMTP Host thence y'all volition demand to furnish few to a greater extent than properties e.g. mail.smtp.port=547 for TLS together with mail.smtp.port=457 for SSL. Here is a consummate Java plan which connect to default SMTP Server without authentication together with ship a text electronic mail using Java's postal service API.

import java.util.Properties; import javax.mail.Message; import javax.mail.MessagingException; import javax.mail.Session; import javax.mail.Transport; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeMessage;  /** * Java Program to ship text postal service using default SMTP server together with without authentication. * You demand mail.jar, smtp.jar together with activation.jar to run this program. * * @author Javin Paul */ public class EmailSender{      public static void main(String args[]) {         String to = "receive@abc.om";            // sender email         String from = "sender@abc.com";       // receiver email         String host = "127.0.0.1";                   // postal service server host         Properties properties = System.getProperties();         properties.setProperty("mail.smtp.host", host);          Session session = Session.getDefaultInstance(properties); // default session          try {             MimeMessage message = new MimeMessage(session);        // electronic mail message             message.setFrom(new InternetAddress(from));                    // setting header fields             message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));             message.setSubject("Test Mail from Java Program"); // discipline line              // actual postal service body             message.setText("You tin ship postal service from Java plan past times using postal service API, but y'all need"                     + "couple of to a greater extent than JAR files e.g. smtp.jar together with activation.jar");              // Send message             Transport.send(message);             System.out.println("Email Sent successfully....");         } catch (MessagingException mex) {             mex.printStackTrace();         }     }  }  Output : 
You tin Compile and run this plan to ship a uncomplicated e-mail from Java program:  $ javac EmailSender.java $ coffee EmailSender Sent electronic mail successfully.... 
 

As y'all tin come across it's rattling uncomplicated to ship mails from Java program. Once y'all convey created MimeMessage object, y'all demand to add together recipients which tin live TO, CC or BCC. After setting recipients nosotros convey setup discipline together with lastly electronic mail content itself past times message.setText().  If y'all desire to ship an e-mail to multiple electronic mail ids thence next methods would live used to specify those recipients:

void addRecipients(Message.RecipientType type, Address[] addresses) throws MessagingException

You tin add together peoples into TO plain past times using Message.RecipientType.TO, inwards CC past times Message.RecipientType.CC together with into BCC past times Message.RecipientType.BCC.

Error together with Exception

When many Java programmers commencement start to write plan to ship email, they ran into this fault because close of them simply intend that mail.jar together with activation.jar would live plenty to ship postal service cast Java application, which is non truthful particularly if y'all are sending electronic mail via local SMTP server inwards Linux. If y'all run this plan alongside simply mail.jar together with activation.jar inwards your CLASSPATH, y'all volition close probable acquire this error.

Exception 1:

com.sun.mail.util.MailConnectException: Couldn't connect to host, port: localhost, 25; timeout -1;   nested exception is:                java.net.ConnectException: Connection refused: connect                at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1984)                at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:656)                at javax.mail.Service.connect(Service.java:345)                at javax.mail.Service.connect(Service.java:226)                at javax.mail.Service.connect(Service.java:175)                at javax.mail.Transport.send0(Transport.java:253)                at javax.mail.Transport.send(Transport.java:124)                at Testing.main(Testing.java:62) Caused by: java.net.ConnectException: Connection refused: connect                at java.net.DualStackPlainSocketImpl.connect0(Native Method)                at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)                at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)                at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)                at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)                at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)                at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)                at java.net.Socket.connect(Socket.java:579)                at java.net.Socket.connect(Socket.java:528)                at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:301)                at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:229)                at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1950)                ... seven more

Solution : Though solution of this fault is rattling simple, it may straight y'all into dissimilar direction. Since java.net.ConnectException: Connection refused: connect commonly come upwards when either server is downward or the port y'all are connecting is non correct, together with this happened to me equally good inwards past. solution is apart from mail-1.4.5.jar, y'all too demand smtp-1.4.4.jar together with activation-1.1.jar


Exception 2:
This is roughly other error, called NoClassDefFoundError, which is too related to missing JAR file inwards Classpath :

Exception inwards thread "main" java.lang.NoClassDefFoundError: javax/mail/MessagingException         at java.lang.Class.getDeclaredMethods0(Native Method)         at java.lang.Class.privateGetDeclaredMethods(Class.java:2521)         at java.lang.Class.getMethod0(Class.java:2764)         at java.lang.Class.getMethod(Class.java:1653)         at sun.launcher.LauncherHelper.getMainMethod(LauncherHelper.java:494)         at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:486) Caused by: java.lang.ClassNotFoundException: javax.mail.MessagingException         at java.net.URLClassLoader$1.run(URLClassLoader.java:366)         at java.net.URLClassLoader$1.run(URLClassLoader.java:355)         at java.security.AccessController.doPrivileged(Native Method)         at java.net.URLClassLoader.findClass(URLClassLoader.java:354)         at java.lang.ClassLoader.loadClass(ClassLoader.java:424)         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)         at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

Solution : I managed to resolve my problem, it was because of wrong Classpath. Even though I had all 3 required JAR together with Java cast file for plan inwards same directory together with I am running plan from there, Java wasn't able to resolve that. I tried next ascendence together with it worked perfectly for me :

java -cp mail-1.4.5.jar:smtp-1.4.4.jar:activation-1.1.jar:. JavaMailSender Sent electronic mail successfully....

Please notice electrical flow directory denoted past times point (.) at the terminate of Classpath argument. Since I was running my plan on Linux, I convey used colon equally separator (:) instead of Windows semi colon (;)

That's all on how to ship electronic mail from Java plan using postal service API. You tin come across it's rattling simple, apart from 3 JAR file y'all don't demand much. It's much slowly if y'all job Gradle or Maven for dependency management.  In side past times side yoke of tutorials nosotros volition come across advanced representative of Java's postal service API to ship electronic mail alongside attachments, alongside images together with nicely HTML formatted emails to ship reports together with tables.

Further Learning
Java Web Fundamentals By Kevin Jones
Java EE alongside Vaadin, Spring Boot together with Maven
Spring Framework Master Class - Beginner to Expert

Sumber https://javarevisited.blogspot.com/

Share this post