javamail的几个实用知识点.

最新推荐文章于 2025-11-22 21:35:13 发布

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本文介绍了使用JavaMail发送和处理邮件的几个实用技巧，包括将邮件保存为文件以便客户端打开、对邮件体使用Base64编码、启动调试模式以及如何连接验证SMTP服务器。

javamail的几个实用知识点.
1.把邮件保存为一个文件，这个文件可以直接用Outlook,Foxmail等邮件客户端工具打开。

private void savemail(MimeMessage msg, String path) {
try {
File f = new File(path);
f.getParentFile().mkdirs();
FileOutputStream fo = new FileOutputStream(f);
//CRLFOutputStream 可以把一些换行符不满足MIME规范的邮件进行修正。
CRLFOutputStream CRLFO = new CRLFOutputStream(fo);
msg.writeTo(CRLFO);
CRLFO.close();
fo.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}

调用：

savemail(msg,"c:/lizongbo/testmail.eml");

2.对邮件体使用base64编码。

默认情况下使用的是quoted-printable编码：
示例如下：

MimeMessage msg = new MimeMessage((Session)null);
msg.setFrom(new InternetAddress("lizongbo@gmail.com"));
msg.setRecipient(Message.RecipientType.TO,
new InternetAddress("lizongbo@msn.com"));
msg.setText("测试一下，邮件来自 http://www.donews.net/lizongbo !!!");
msg.setSubject("测试标题！！！", "GB2312");
MimeMultipart multipart = new MimeMultipart();
MimeBodyPart txtbodyPart = new MimeBodyPart();
txtbodyPart.setText("这是一封html邮件，请用html方式察看！！！");
multipart.addBodyPart(txtbodyPart);
MimeBodyPart htmlodyPart = new MimeBodyPart();
String content="html邮件内容！来自 http://www.donews.net/lizongbo ";
content = "<html><body>" + content + "</body><html>";
htmlodyPart.setContent(content, "text/html;charset=GBK");
multipart.addBodyPart(htmlodyPart);
msg.setContent(multipart);
msg.saveChanges();
得到的邮件内容为：
--------------------------------------------------------------
Message-ID: <32591083.1110043294640.JavaMail.lizongbo@localhost>

From: lizongbo@gmail.com

To: lizongbo@msn.com

Subject: =?GB2312?B?suLK1LHqzOKjoaOho6E=?=

Mime-Version: 1.0

Content-Type: multipart/mixed; boundary="----=_Part_0_8568863.1110043294484"

------=_Part_0_8568863.1110043294484

Content-Type: text/plain; charset=GBK

Content-Transfer-Encoding: base64

1eLKx9K7t+JodG1s08q8/qOsx+vTw2h0bWy3vcq9suy/tKOho6GjoQ==

------=_Part_0_8568863.1110043294484

Content-Type: text/html;charset=GBK

Content-Transfer-Encoding: quoted-printable

<html><body>html=D3=CA=BC=FE=A3=A1 http://www.donews.net/lizongbo </body><h=

tml>

------=_Part_0_8568863.1110043294484--

--------------------------------------------------------------

使用base64编码的代码：
--------------------------------------------------------------
MimeMessage msg = new MimeMessage( (Session)null);
msg.setFrom(new InternetAddress("lizongbo@gmail.com"));
msg.setRecipient(Message.RecipientType.TO,
new InternetAddress("lizongbo@msn.com"));
msg.setText("测试一下，邮件来自 http://www.donews.net/lizongbo !!!");
msg.setSubject("测试标题！！！", "GB2312");
MimeMultipart multipart = new MimeMultipart();
MimeBodyPart txtbodyPart = new MimeBodyPart();
txtbodyPart.setText("这是一封html邮件，请用html方式察看！！！");
multipart.addBodyPart(txtbodyPart);
MimeBodyPart htmlodyPart = new MimeBodyPart();
String content = "html邮件！ http://www.donews.net/lizongbo ";
content = "<html><body>" + content + "</body><html>";
htmlodyPart.setContent(content, "text/html;charset=GBK");
//最最关键的就这么一行
htmlodyPart.setHeader("Content-Transfer-Encoding", "base64");
multipart.addBodyPart(htmlodyPart);
msg.setContent(multipart);
msg.saveChanges();

得到邮件内容如下：

--------------------------------------------------------------
Message-ID: <33109165.1110043370875.JavaMail.lizongbo@localhost>

From: lizongbo@gmail.com

To: lizongbo@msn.com

Subject: =?GB2312?B?suLK1LHqzOKjoaOho6E=?=

Mime-Version: 1.0

Content-Type: multipart/mixed; boundary="----=_Part_0_8568863.1110043370687"

------=_Part_0_8568863.1110043370687

Content-Type: text/plain; charset=GBK

Content-Transfer-Encoding: base64

1eLKx9K7t+JodG1s08q8/qOsx+vTw2h0bWy3vcq9suy/tKOho6GjoQ==

------=_Part_0_8568863.1110043370687

Content-Type: text/html;charset=GBK

Content-Transfer-Encoding: base64

PGh0bWw+PGJvZHk+aHRtbNPKvP6joSBodHRwOi8vd3d3LmRvbmV3cy5uZXQvbGl6b25nYm8gPC9i

b2R5PjxodG1sPg==

------=_Part_0_8568863.1110043370687--

3.启动javamail的调试模式,可以在发送和接收邮件的时候方便查看详细的调试信息，只需要：

//Session session = Session.getInstance(System.getProperties());
session.getProperties().setProperty("mail.debug","true");
session.setDebug(true);
//默认的是输出调试信息到控制台

4.显式连接到需要验证的smtp服务器进行邮件发送。
一般的资料都说是自己继承javax.mail.Authenticator.
代码如下：

package com.lizongbo.javamail;

import javax.mail.*;

public class MailAuthenticator extends Authenticator {
public MailAuthenticator() {
}

private String mUser;
private String mPass;

public MailAuthenticator(String userName, String passWord) {
super();
mUser = userName;
mPass = passWord;
}

public PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(mUser, mPass);
}

}

调用的示例：
Session session = Session.getInstance(System.getProperties(),new MailAuthenticator ("lizongbo","password") );
MimeMessage msg = new MimeMessage(session);
Transport.send(msg);

其实也可以不继承这个class,而是直接使用用户名和密码连接到邮件服务器进行邮件发送操作。
MimeMessage msg = new MimeMessage( (Session)null);
msg.setFrom(new InternetAddress("lizongbo@gmail.com"));
msg.setRecipient(Message.RecipientType.TO,
new InternetAddress("lizongbo@msn.com"));
//中间代码略去
msg.saveChanges();
Transport smtpTransport = session.getTransport("smtp");
smtpTransport.connect("smtp.163.com", 25, "lizongbo", "password");
//切忌不可以使用 smtpTransport.send(msg)和smtpTransport.send(msg,msg.getAllRecipients());
//因为这两个是静态方法,无法获取与smtpTransport这个实例有关的参数.
smtpTransport.sendMessage(msg, msg.getAllRecipients());

具体可以通过阅读javamail1.3.2的源代码来发现一些细节差异。

转自
http://blog.donews.com/lizongbo/archive/2005/03/06/295806.aspx