Javamail 邮件回复
邮件的回复的代码很简单，在迭代邮件的信息的时候调用MimeMessage reply = (MimeMessage) messages[i].reply(Boolean ) TRUE 是邮件回复给发送者，FALSE恢复给所有人。如果要回复到新的收件人请使用SetReply-to。
同时可以使用 reply.setSubject(“***”)设置回复的标题，不设置的话默认是Re: 加上接收到邮件的标题。同理，也可以自己设置正文内容。
这里一定要设置发送邮件的地址，而且必须要和邮件认证的用户名一致，不然会报错。
最后调用Transport.send(reply)将邮件发出去
注意：1、reply.setFrom() 必须要设置而且要和邮件认证的用户名一致，不然会报以下错误：
com.sun.mail.smtp.SMTPSendFailedException: 501 mail from address must be same as authorization user
2、建议使用邮件认证登陆邮件服务器，不然会出现以下错误：
javax.mail.AuthenticationFailedException: failed to connect, no password specified?
3、代码虽然很简单，但是程序难免会出现各种异常。如果大家在调试程序的时候出现错误，请给我留言。
给一个成功例子大家参考：.
import java.io.*; import java.util.*; import javax.mail.*; import javax.mail.internet.*; public class ReplyMail { private static final String HOST_NAME = "pop.qq.com"; private static final String SEND_HOST_NAME = "smtp.qq.com"; private static final String PASSWORD = "*******"; private static final String EMAIL_FROM = "flyingsam@qq.com"; private static final String USER_NAME = "flyingsam@qq.com"; private static final String PROTOCOL = "pop3"; private static final String SEND_PROTOCOL = "smtp"; public static void listMail() throws Exception { Properties props = new Properties(); props.put("mail.smtp.host", SEND_HOST_NAME); props.put("mail.pop.host", HOST_NAME); props.put("mail.transport.protocol","smtp"); props.put("mail.smtp.auth", "true"); Session session = Session.getDefaultInstance(props, new SimpleAuthenticator(USER_NAME, PASSWORD)); Store store = session.getStore(ReplyMail.PROTOCOL); store.connect(HOST_NAME, USER_NAME, PASSWORD); Folder folder = store.getFolder("INBOX"); folder.open(Folder.READ_ONLY); Message[] messages = folder.getMessages(); InternetAddress address; for (int i = messages.length-1; i >= 0; i--) { address = (InternetAddress)messages[i].getFrom()[0]; if(address != null) { System.out.println(address.getPersonal()); } if (null != address && "秋天的童话".equals(address.getPersonal())) { System.out.println("第" + i + "个：" + messages[i].getSubject()); MimeMessage replyMessage = (MimeMessage) messages[i].reply(false); // replyMessage.setFrom(new InternetAddress(EMAIL_FROM)); replyMessage.setRecipients(MimeMessage.RecipientType.TO, address.getAddress()); replyMessage.setText("这是回复邮件，不知道能否成功！"); replyMessage.saveChanges(); Transport transport = session.getTransport("smtp"); transport.connect(SEND_HOST_NAME, USER_NAME, PASSWORD); transport.send(replyMessage); System.out.println("回复成功"); } } folder.close(true); store.close(); } public static void main(String[] args) { try { ReplyMail.listMail(); } catch (Exception e) { e.printStackTrace(); } } }public class SimpleAuthenticator extends Authenticator { private String username; private String password; public SimpleAuthenticator(String username, String password) { this.username = username; this.password = password; } public PasswordAuthentication getPasswordAuthentication() { return new PasswordAuthentication(this.username, this.password); } }