介绍
发送邮件是一个很常见的需求，如用户注册，用户密码修改，密码找回等。今天我们看一下使用JavaSE和Spring实现发送邮件的功能。
邮件协议
SMTP协议是基于TCP/IP的一个应用层协议，类似于HTTP，全称为 Simple Mail Transfer Protocol，译作简单邮件传输协议，它定义了邮件客户端软件与SMTP 服务器之间，以及 SMTP 服务器与 SMTP 服务器之间的通信规则。我们通过邮件客户端或程序发送邮件时就用到了该协议。
而 POP3 协议全称为 Post Office Protocol ，译作邮局协议，它定义了邮件客户端与 POP3服务器之间的通信规则。我们通过邮件客户端查看邮件时就用到了该协议。
IMAP（Internet Message Access Protocol）协议是对POP3协议的一种扩展，功能更强，作用类似。
发送前准备
发送前需要获取邮箱的授权码，以网易126邮箱为例
使用JavaSE发送简单邮件
添加maven依赖
<dependency>
<groupId>com.sun.mail</groupId>
<artifactId>javax.mail</artifactId>
<version>1.6.2</version>
</dependency>
发送邮件
public class Client {
public static void main(String[] args) throws Exception {
Properties props = new Properties();
//设置邮件地址
props.put("mail.smtp.host", "smtp.126.com");
//开启认证
props.put("mail.smtp.auth", "true");
Session session = Session.getDefaultInstance(props, null);
Transport transport = session.getTransport();
//用户名
String user = "xxx@126.com";
//授权码
String password = "xxx";
transport.connect(user, password);
//创建邮件消息
MimeMessage msg = new MimeMessage(session);
msg.setSentDate(new Date());
//邮件发送人
InternetAddress fromAddress = new InternetAddress(user, "邮件服务");
msg.setFrom(fromAddress);
//邮件接收人
String to = "xxx@163.com";
InternetAddress[] toAddress = new InternetAddress[]{new InternetAddress(to)};
msg.setRecipients(Message.RecipientType.TO, toAddress);
//邮件主题
msg.setSubject("测试邮件发送", "UTF-8");
//邮件内容和格式
msg.setContent("this is a test mail", "text/html;charset=UTF-8");
msg.saveChanges();
//发送
transport.sendMessage(msg, msg.getAllRecipients());
}
}
发送带附件的邮件
public class Client {
public static void main(String[] args) throws Exception {
Properties props = new Properties();
//设置邮件地址
props.put("mail.smtp.host", "smtp.126.com");
//开启认证
props.put("mail.smtp.auth", "true");
Session session = Session.getDefaultInstance(props, null);
Transport transport = session.getTransport();
//用户名
String user = "xxx@126.com";
//授权码
String password = "xxx";
transport.connect(user, password);
//创建邮件消息
MimeMessage msg = new MimeMessage(session);
msg.setSentDate(new Date());
//邮件发送人
InternetAddress fromAddress = new InternetAddress(user, "邮件服务");
msg.setFrom(fromAddress);
//邮件接收人
String to = "xxx@163.com";
InternetAddress[] toAddress = new InternetAddress[]{new InternetAddress(to)};
msg.setRecipients(Message.RecipientType.TO, toAddress);
//邮件主题
msg.setSubject("测试邮件发送", "UTF-8");
//内容和附件
Multipart multipart = new MimeMultipart();
//内容
BodyPart contentBodyPart = new MimeBodyPart();
contentBodyPart.setContent("this also is a test mail", "text/html;charset=UTF-8");
multipart.addBodyPart(contentBodyPart);
//附件
BodyPart fileBody = new MimeBodyPart();
DataSource source = new FileDataSource("D:/a.png");
fileBody.setDataHandler(new DataHandler(source));
fileBody.setFileName("测试附件.png");
multipart.addBodyPart(fileBody);
//邮件内容
msg.setContent(multipart);
msg.saveChanges();
//发送
transport.sendMessage(msg, msg.getAllRecipients());
}
}
使用Spring发送简单邮件
spring在原有的基础上又封装了一层，简化了开发。
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>5.1.2.RELEASE</version>
</dependency>
<dependency>
<groupId>com.sun.mail</groupId>
<artifactId>javax.mail</artifactId>
<version>1.6.2</version>
</dependency>
public class Client {
public static void main(String[] args) throws Exception {
JavaMailSender mailSender = createJavaMailSender();
//创建邮件消息
MimeMessage mimeMessage = mailSender.createMimeMessage();
MimeMessageHelper messageHelper = new MimeMessageHelper(mimeMessage);
//发送人
messageHelper.setFrom("xxx@126.com", "邮件服务");
//收件人
messageHelper.setTo("xxx@163.com");
//主题
messageHelper.setSubject("测试邮件发送");
//发送时间
messageHelper.setSentDate(new Date());
//发送内容
messageHelper.setText("this is a test mail by spring");
mailSender.send(mimeMessage);
}
private static JavaMailSender createJavaMailSender() {
JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
mailSender.setDefaultEncoding(StandardCharsets.UTF_8.name());
String username = "xxx@126.com";
//设置用户名
mailSender.setUsername(username);
//设置授权码
mailSender.setPassword("xxx");
Properties props = new Properties();
//设置邮件地址
props.put("mail.smtp.host", "smtp.126.com");
//开启认证
props.put("mail.smtp.auth", "true");
mailSender.setJavaMailProperties(props);
return mailSender;
}
}
使用Spring发送带附件的邮件
public class Client {
public static void main(String[] args) throws Exception {
JavaMailSender mailSender = createJavaMailSender();
//创建邮件消息
MimeMessage mimeMessage = mailSender.createMimeMessage();
//multipart为true表示可以带附件
MimeMessageHelper messageHelper = new MimeMessageHelper(mimeMessage, true);
//发送人
messageHelper.setFrom("xxx@126.com", "邮件服务");
//收件人
messageHelper.setTo("xxx@163.com");
//主题
messageHelper.setSubject("测试邮件发送");
//发送时间
messageHelper.setSentDate(new Date());
//发送内容
messageHelper.setText("this is a test mail by spring");
//添加附件
messageHelper.addAttachment("测试附件.png", new FileDataSource("D:/a.png"));
mailSender.send(mimeMessage);
}
private static JavaMailSender createJavaMailSender() {
JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
mailSender.setDefaultEncoding(StandardCharsets.UTF_8.name());
String username = "xxx@126.com";
//设置用户名
mailSender.setUsername(username);
//设置授权码
mailSender.setPassword("xxx");
Properties props = new Properties();
//设置邮件地址
props.put("mail.smtp.host", "smtp.126.com");
//开启认证
props.put("mail.smtp.auth", "true");
mailSender.setJavaMailProperties(props);
return mailSender;
}
}