Shulou(Shulou.com)06/02 Report--

This article is to share with you about how to develop Java Mail API. The editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

1. Introduction:

The development of Java Mail API is a good example of SUN's ongoing efforts to provide a common API framework for Java developers. Advocating a common framework and opposing vendor-constrained solutions fully heralds the establishment of an increasingly open development environment.

The structure of Java Mail API itself proves that one of the basic goals of its developers-the amount of software development work should depend on the complexity of the application itself and the degree of control required by the developer. In other words, Java Mail API is kept as simple as possible. At first glance, the total number of classes JavaMail API has and the relationships between them may be misunderstood as taking a long time to learn. In fact, once you start using it, you will find that API is a simple tool to add robust mail / communication support to your application.

two。 Installation:

Before installation, make sure that your machine has standard JDK and Web servers installed and configured. For installation methods, please refer to other articles (available all over the Internet).

(1)。 Install JavaMail API. Now the most commonly used version of JavaMail API is 1. 3.

To use JavaMail 1.3 API, download the JavaMail 1.3 implementation, unpack the Javamail-1_3.zip file, and add the mail.jar file to CLASSPATH. In addition to the core classes, SMTP, IMAP4, and POP3 vendors are included with the version 1.3 implementation.

(2) installation of JavaBeans Activation Framework (version 1.0.2)

All versions of JavaMail API require JavaBeans Activation Framework to support the input and processing of arbitrary blocks of data. There doesn't seem to be much functionality, but this basic MIME-type support can be found in many browsers and mail tools. After downloading the framework, unpack the jaf1_0_2.zip file and add the activation.jar file to the CLASSPATH.

Note: if the JDK you are using is J2EE, there is nothing specific that needs to be done with basic JavaMail API; the class of J2EE can handle it because it itself contains JavaMail API and JAF, and you just need to make sure that the j2ee.jar file is added to your CLASSPATH and all set up.

Introduction to common classes of 3.JavaMail

State in advance:

People who have not used JavaMail may not understand these introductions, but never mind, the following article has specific examples, and then you can look back at the usage of these classes.

(1) javax.mail.Properties class

JavaMail requires Properties to create a session object. It will look for the string "mail.smtp.host", and the attribute value is the host from which the message is sent.

Usage:

Properties props = new Properties ()

Props.put ("mail.smtp.host", "smtp.163.com"); / / you can change your smtp host name.

(2) javax.mail.Session class

This Session class represents a mail session in JavaMail. Every JavaMail-based application has at least one session but can have as many session as you want. In this example, the Session object needs to know the SMTP server used to process the mail.

Usage:

Session sendMailSession

SendMailSession = Session.getInstance (props, null)

(3) javax.mail.Transport class

E-mail can be sent or received. JavaMail uses two different classes to accomplish these two functions: Transport and Store. Transport is used to send messages, while Store is used to receive mail. For this tutorial, we only need to use the Transport object.

Usage:

Transport transport

Transport = sendMailSession.getTransport ("smtp")

Initialize the Transport with the getTransport method of the JavaMail Session object. The passed string declares the protocol to be used by the object, such as "smtp". This will save us a lot of time. Because JavaMail has built a lot of protocol implementation methods in China.

Note: JavaMail does not absolutely support every protocol, and currently supports IMAP, SMTP and POP3.

(4) javax.mail.MimeMessage class

The Message object will store the e-mail information we actually sent, and the Message object is created as a MimeMessage object and we need to know which JavaMail session should be selected.

Usage:

Message newMessage = new MimeMessage (sendMailSession)

(5) javax.mail.InternetAddress class

Once you have created Session and Message and filled the contents into the message, you can use Address to determine the address of the letter. Like Message, Address is an abstract class. You are using the Javax.mail.internet.InternetAddress class.

Usage:

InternetAddress from=new InternetAddress ("xxf@cafe.com")

(6) javax.mail.Store class

The Store class implements operations such as reading, writing, monitoring, lookup, and so on, on specific mail protocols. The Javax.mail.Folder class can be accessed through the Javax.mail.Store class.

Usage:

Store store=s.getSorte ("pop3"); / / s is a mail session

Store.connect (popserver,username,password); / / Log in to your email with the pop address, user name and password you provided

(7) javax.mail.Folder class

The Folder class is used to organize messages hierarchically and provides the ability to access email in Javax.mail.Message format.

Usage:

Folder folder=store.getFolder ("INBOX")

Folder.open (Folder.READ_ONLY)

(8) javax.mail.Internet.MimeMultpart

Generally speaking, the container for storing e-mail content is the Multipart abstract class, which defines the methods of adding and deleting and obtaining different parts of e-mail content. Since Multipart is an abstract class, we must use a concrete subclass for it. JavaMail API provides the javax.mail.Internet.MimeMultpart class to use the MimeMessage object.

Usage:

MimeMultipart multipart=new MimeMultipart ()

Note: one way we use the MimeMultipart object is addBodyPart (), which adds a BodyPart object to our email content (the BodyPart class is described next). A message can have many parts, and a BodyPart can represent a part.

(9) javax.mail.Internet.MimeBodyPart class

MimeBodyPart is a subclass of BodyPart specifically used for mimeMessage.

The MimeBodyPart object represents part of the content of a MimeMessage object. Each MimeBodyPart is considered to have two parts:

⊙ a MIME type

⊙ matches this type of content

Usage:

MimeBodyPart mdp=new MimeBodyPart ()

String text= "Hello JavaMail!"

Mdp.setContent (text, "text/plain"); / / define the MIME type as text/plain, and set the content of MimeBodyPart.

(10) javax.activation.DataHandler class (included in JAF)

JavaMail API does not restrict information to text, and any form of information may be part of a self-contained MimeMessage. In addition to text messages, it is common to be included in e-mail messages as file attachments. JavaMail API provides an easy way to allow us to include non-text BodyPart objects by using DataHandler objects.

Usage:

DataHandler dh=new DataHandler (text,type)

Mdp.setDatahandler (dh); / / mdp is a MimeBodyPart object

(11) javax.activation.FileDataSource class (included in JAF)

A FileDataSource object can represent local files and resources that can be accessed directly by the server. A local file can be attached to a mimeMessage object by creating a new MimeBodyPart object.

Usage:

MimeMultipart mm=new MimeMultipart ()

MimeBodyPart mdp=new MimeBodyPart ()

FileDataSource fds=new FileDataSource ("c:/exam.txt")

Mdp.setDataHandler (new DataHandler (fds)); / / set the data source

Mm.addBodyPart (mdp); / / add MimeBodyPart to the current message MimeMultipart object

(12) javax.activation.URLDataSource class (included in JAF)

Remote resources, which URL does not point to, are represented by a URLDataSource object. A remote resource can be attached to a mimeMessage object by creating a new mimeBodyPart object (similar to FileDataSource).

Usage:

The only difference from FileDataSource is the settings for the data source:

URLDataSource uds=new URLDataSource (https://cache.yisu.com/upload/information/20200703/145/53442.gif)

4. Try to write the first sending program

We have made some introduction to JavaMail earlier, so we can try to write our own program.

First, let's write an email-composing html program, index.htm, as follows:

-

< html >

< head >

< meta http-equiv="Content-Type" content="text/html; charset=gb2312" >

< title >

Compose an email

< /title >

< /head >

< body >

< form name="form1" method="post" action="testmail.jsp" >

< table width="75" border="0" align="center" cellspacing="1" bgcolor="#006600" class="black" >

< tr bgcolor="#FFFFFF" >

< td width="24%" >

Address of addressee:

< /td >

< td width="76%" >

< input name="to" type="text" id="to" >

< /td >

< /tr >

< tr bgcolor="#FFFFFF" >

< td >

Themes:

< /td >

< td >

< input name="title" type="text" id="title" >

< /td >

< /tr >

< tr >

< td height="107" colspan="2" bgcolor="#FFFFFF" >

< textarea name="content" cols="50" rows="5" id="content" >

< /textarea >

< /td >

< /tr >

< tr align="center" >

< td colspan="2" bgcolor="#FFFFFF" >

< input type="submit" name="Submit" value="发送" >

< input type="reset" name="Submit2" value="重置" >

< /td >

< /tr >

< /table >

< /form >

< /body >

< /html >

Next, we write another handler, testmail.jsp, as follows:

-

< %@ page contentType="text/html;charset=GB2312" % >

< %request.setCharacterEncoding("gb2312");% >

< !--中文处理代码-- >

< !--引入要用到的类库-- >

< %@ page import="java.util.*,javax.mail.*"% >

< %@ page import="javax.mail.internet.*"% >

< html >

< head >

< meta http-equiv="Content-Type" content="text/html; charset=gb2312" >

< title >

Sent successfully

< /title >

< /head >

< body >

< % try{ //从html表单中获取邮件信息 String tto=request.getParameter("to"); String ttitle=request.getParameter("title"); String tcontent=request.getParameter("content"); Properties props=new Properties();//也可用Properties props = System.getProperties(); props.put("mail.smtp.host","smtp.163.net");//存储发送邮件服务器的信息 props.put("mail.smtp.auth","true");//同时通过验证 Session s=Session.getInstance(props);//根据属性新建一个邮件会话 s.setDebug(true); MimeMessage message=new MimeMessage(s);//由邮件会话新建一个消息对象 //设置邮件 InternetAddress from=new InternetAddress("boy@163.net"); message.setFrom(from);//设置发件人 InternetAddress to=new InternetAddress(tto); message.setRecipient(Message.RecipientType.TO,to);//设置收件人,并设置其接收类型为TO message.setSubject(ttitle);//设置主题 message.setText(tcontent);//设置信件内容 message.setSentDate(new Date());//设置发信时间 //发送邮件 message.saveChanges();//存储邮件信息 Transport transport=s.getTransport("smtp"); transport.connect("smtp.163.net","boy","iloveyou");//以smtp方式登录邮箱 transport.sendMessage(message,message.getAllRecipients());//发送邮件,其中第二个参数是所有 //已设好的收件人地址 transport.close(); % >

< div align="center" >

< p >

< font color="#FF6600" >

Sent successfully!

< /font >

< /p >

< p >

< a href="recmail.jsp" >

Check my mailbox.

< /a >

< br >

< br >

< a href="index.htm" >

Send another letter.

< /a >

< /p >

< /div >

< % }catch(MessagingException e){ out.println(e.toString()); } % >

< /body >

< /html >

* * Note * *

There are many books and online articles that write testmail.jsp like this in key sections, as follows:

String tto=request.getParameter ("to")

String ttitle=request.getParameter ("title")

String tcontent=request.getParameter ("content")

Properties props=new Properties ()

Props.put ("mail.smtp.host", "smtp.163.net")

Session s=Session.getInstance (props)

MimeMessage message=new MimeMessage (s)

InternetAddress from=new InternetAddress ("boy@163.net")

Message.setFrom (from)

InternetAddress to=new InternetAddress (tto)

Message.setRecipient (Message.RecipientType.TO,to)

Message.setSubject (ttitle)

Message.setText (tcontent)

Message.setSentDate (new Date ())

Store store=s.getStore ("pop3")

Store.connect ("pop.163.net", "boy", "iloveyou"); / / log in to the mailbox as pop3

Transport transport=s.getTransport ("smtp")

Transport.send (message)

Store.close ()

In fact, this method is not reliable, because the smtp servers of many e-mail offices require us to pass authentication, so when sending mail in this way, it can only be sent to the same kind of mailbox (that is, the same smtp mailbox), and sometimes the same kind of mailbox can not be sent. I have tried the above two methods many times, and it turns out that the first one is the most reliable.

OK, I believe you should be able to write the simplest Email sending program. OK, next time we will talk about how to write and send an email in HTML format.

5. Send a message in HTML format

The so-called HTML format is the hypertext format. Your email can be written in HTML code, and after sending it to the other party, the message will be hypertext, which is much better than plain text. The following is a modified program based on the previous example:

< %@ page contentType="text/html;charset=GB2312" % >

< %request.setCharacterEncoding("gb2312");% >

< %@ page import="java.util.*,javax.mail.*"% >

< %@ page import="javax.mail.internet.*"% >

< html >

< head >

< meta http-equiv="Content-Type" content="text/html; charset=gb2312" >

< title >

Sent successfully

< /title >

< /head >

< body >

< % try{ String tto=request.getParameter("to"); String ttitle=request.getParameter("title"); String tcontent=request.getParameter("content"); Properties props=new Properties(); props.put("mail.smtp.host","127.0.0.1"); props.put("mail.smtp.auth","true"); Session s=Session.getInstance(props); s.setDebug(true); MimeMessage message=new MimeMessage(s); //给消息对象设置发件人/收件人/主题/发信时间 InternetAddress from=new InternetAddress("xxf@cafe.com"); message.setFrom(from); InternetAddress to=new InternetAddress(tto); message.setRecipient(Message.RecipientType.TO,to); message.setSubject(ttitle); message.setSentDate(new Date()); //给消息对象设置内容 BodyPart mdp=new MimeBodyPart();//新建一个存放信件内容的BodyPart对象 mdp.setContent(tcontent,"text/html;charset=gb2312");//给BodyPart对象设置内容和格式/编码方式 Multipart mm=new MimeMultipart();//新建一个MimeMultipart对象用来存放BodyPart对 //象(事实上可以存放多个) mm.addBodyPart(mdp);//将BodyPart加入到MimeMultipart对象中(可以加入多个BodyPart) message.setContent(mm);//把mm作为消息对象的内容 message.saveChanges(); Transport transport=s.getTransport("smtp"); transport.connect("127.0.0.1","xxf","coffee"); transport.sendMessage(message,message.getAllRecipients()); transport.close(); % >

< div align="center" >

< p >

< font color="#FF6600" >

Sent successfully!

< /font >

< /p >

< p >

< a href="recmail.jsp" >

Check my mailbox.

< /a >

< br >

< br >

< a href="index.htm" >

Send another letter.

< /a >

< /p >

< /div >

< % }catch(MessagingException e){ out.println(e.toString()); } % >

< /body >

< /html >

Note: the html file for composing the email is still the same as the previous one (please refer to jsp and Java Mail (3)) and does not need to be modified.

So, is this program very simple? If there is anything else you don't understand, please leave a message below. Next time we will talk about how to send attachments.

seven。 Write a flexible sending program

Nothing new has been added to this section, but it combines all the previous content and gives you the flexibility to send the email you want. After reading this section, you will feel very useful.

The changed writing interface program is as follows:

-

< html >

< head >

< meta http-equiv="Content-Type" content="text/html; charset=gb2312" >

< title >

Compose an email

< /title >

< /head >

< body >

< form action="testall.jsp" method="post" name="form1" >

< table width="75" border="0" align="center" cellspacing="1" bgcolor="#006600" class="black" >

< tr bgcolor="#FFFFFF" >

< td width="24%" >

Address of addressee:

< /td >

< td width="76%" >

< input name="to" type="text" id="to" >

< /td >

< /tr >

< tr bgcolor="#FFFFFF" >

< td >

Themes:

< /td >

< td >

< input name="title" type="text" id="title" >

< /td >

< /tr >

< tr >

< td height="18" colspan="2" bgcolor="#FFFFFF" >

Letter type

< select name="emailtype" id="emailtype" >

< option value="text/plain" selected >

Text

< /option >

< option value="text/html" >

Html

< /option >

< /select >

< /td >

< /tr >

< tr >

< td height="53" colspan="2" bgcolor="#FFFFFF" >

< textarea name="content" cols="50" rows="5" id="content" >

< /textarea >

< /td >

< /tr >

< tr align="center" >

< td colspan="2" bgcolor="#FFFFFF" >

Annex 1 (Custom):

< input name="fj1" type="text" id="fj1" >

(enter text information)

< /td >

< /tr >

< tr align="center" valign="bottom" >

< td colspan="2" bgcolor="#FFFFFF" >

Annex 2 (Local):

< input name="fj2" type="file" id="fj2" size="10" >

< /td >

< /tr >

< tr align="center" >

< td colspan="2" bgcolor="#FFFFFF" >

Annex 3 (remote):

< input name="fj3" type="text" id="fj3" value="http://" >

(enter URL)

< /td >

< /tr >

< tr align="center" >

< td colspan="2" bgcolor="#FFFFFF" >

< input type="submit" name="Submit" value="发送" >

< input type="reset" name="Submit2" value="重置" >

< /td >

< /tr >

< /table >

< /form >

< /body >

< /html >

The JSP program for handling messages is as follows:

-

< %@ page contentType="text/html;charset=GB2312" % >

< %request.setCharacterEncoding("gb2312");% >

< %@ page import="java.util.*,javax.mail.*"% >

< %@ page import="javax.mail.internet.*"% >

< %@ page import="javax.activation.*"% >

< !--要发送附件必须引入该库-- >

< %@ page import="java.net.*"% >

< !--要用到URL类-- >

< html >

< head >

< meta http-equiv="Content-Type" content="text/html; charset=gb2312" >

< title >

Sent successfully

< /title >

< /head >

< body >

< % try{ String tto=request.getParameter("to"); String ttitle=request.getParameter("title"); String emailtype=request.getParameter("emailtype");//获取email类型 String tcontent=request.getParameter("content"); String tfj1=request.getParameter("fj1"); String tfj2=request.getParameter("fj2"); String tfj3=request.getParameter("fj3"); Properties props=new Properties(); props.put("mail.smtp.host","127.0.0.1"); props.put("mail.smtp.auth","true"); Session s=Session.getInstance(props); s.setDebug(true); MimeMessage message=new MimeMessage(s); //给消息对象设置发件人/收件人/主题/发信时间 InternetAddress from=new InternetAddress("xxf@cafe.com"); message.setFrom(from); InternetAddress to=new InternetAddress(tto); message.setRecipient(Message.RecipientType.TO,to); message.setSubject(ttitle); message.setSentDate(new Date()); Multipart mm=new MimeMultipart();//新建一个MimeMultipart对象用来存放多个BodyPart对象 //设置信件文本内容 BodyPart mdp=new MimeBodyPart();//新建一个存放信件内容的BodyPart对象 mdp.setContent(tcontent,emailtype+";charset=gb2312");//给BodyPart对象设置内容和格式/编码方式 mm.addBodyPart(mdp);//将含有信件内容的BodyPart加入到MimeMultipart对象中 //设置信件的附件1(自定义附件:直接将所设文本内容加到自定义文件中作为附件发送) mdp=new MimeBodyPart();//新建一个存放附件的BodyPart DataHandler dh=new DataHandler(tfj1,"text/plain;charset=gb2312"); //新建一个DataHandler对象,并设置其内容和格式/编码方式 mdp.setFileName("text.txt");//加上这句将作为附件发送,否则将作为信件的文本内容 mdp.setDataHandler(dh);//给BodyPart对象设置内容为dh mm.addBodyPart(mdp);//将含有附件的BodyPart加入到MimeMultipart对象中 //设置信件的附件2(用本地上的文件作为附件) mdp=new MimeBodyPart(); FileDataSource fds=new FileDataSource(tfj2); dh=new DataHandler(fds); int ddd=tfj2.lastIndexOf(""); String fname=tfj2.substring(ddd);//提取文件名 String ffname=new String(fname.getBytes("gb2312"),"ISO8859-1");//处理文件名是中文的情况 mdp.setFileName(ffname);//可以和原文件名不一致,但最好一样 mdp.setDataHandler(dh); mm.addBodyPart(mdp); //设置信件的附件3(用远程文件作为附件) mdp=new MimeBodyPart(); URL urlfj=new URL(tfj3); URLDataSource ur=new URLDataSource(urlfj); //注:这里用的参数只能为URL对象,不能为URL字串,在前面类介绍时有误(请谅解),这里纠正一下. dh=new DataHandler(ur); int ttt=tfj3.lastIndexOf("/"); String urlname=tfj3.substring(ttt); //String urlfname=new String(urlname.getBytes("gb2312"),"ISO8859-1");//不知怎么回事,这里不能处理中文问题 mdp.setFileName(urlname); mdp.setDataHandler(dh); mm.addBodyPart(mdp); message.setContent(mm);//把mm作为消息对象的内容 message.saveChanges(); Transport transport=s.getTransport("smtp"); transport.connect("127.0.0.1","xxf","coffee"); transport.sendMessage(message,message.getAllRecipients()); transport.close(); % >

< div align="center" >

< p >

< font color="#FF6600" >

Sent successfully!

< /font >

< /p >

< p >

< a href="recmail.jsp" >

Check my mailbox.

< /a >

< br >

< br >

< a href="index.htm" >

Send another letter.

< /a >

< /p >

< /div >

< % }catch(MessagingException e){ out.println(e.toString()); } % >

< /body >

< /html >

So far, we have basically learned to send all kinds of e-mails.

The above is how to develop Java Mail API, and the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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