java里如何判断Email是否发送成功

package com.liuns.mail.test;

import java.util.Date;
import java.util.Properties;
import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.Authenticator;
import javax.mail.BodyPart;
import javax.mail.Message.RecipientType;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import javax.mail.internet.MimeUtility;

public class MailTest {
//发送的邮箱 内部代码只适用qq邮箱
private static final String USER = "xxx@qq.com";

//授权密码 通过QQ邮箱设置->账户->POP3/IMAP/SMTP/Exchange/CardDAV/CalDAV服务->开启POP3/SMTP服务获取
private static final String PWD = "xxx";
private String[] to;
private String[] cc;//抄送
private String[] bcc;//密送
private String[] fileList;//附件
private String subject;//主题
private String content;//内容，可以用html语言写
public void sendMessage() throws Exception {
// 配置发送邮件的环境属性
final Properties props = new Properties();
//下面两段代码是设置ssl和端口，不设置发送不出去。
props.setProperty("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
//props.setProperty("mail.smtp.port", "465");
props.setProperty("mail.smtp.socketFactory.port", "465");
// 表示SMTP发送邮件，需要进行身份验证
props.setProperty("mail.transport.protocol", "smtp");// 设置传输协议
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.host", "smtp.qq.com");//QQ邮箱的服务器 如果是企业邮箱或者其他邮箱得更换该服务器地址
// 发件人的账号
props.put("mail.user", USER);
// 访问SMTP服务时需要提供的密码
props.put("mail.password", PWD);

// 构建授权信息，用于进行SMTP进行身份验证
Authenticator authenticator = new Authenticator() {
@Override
protected PasswordAuthentication getPasswordAuthentication() {
// 用户名、密码
String userName = props.getProperty("mail.user");
String password = props.getProperty("mail.password");
return new PasswordAuthentication(userName, password);
}
};
// 使用环境属性和授权信息，创建邮件会话
Session mailSession = Session.getInstance(props, authenticator);
// 创建邮件消息
MimeMessage message = new MimeMessage(mailSession);
BodyPart messageBodyPart = new MimeBodyPart();
Multipart multipart = new MimeMultipart();
// 设置发件人
InternetAddress form = new InternetAddress(
props.getProperty("mail.user"));
message.setFrom(form);
//发送
if (to != null) {
String toList = getMailList(to);
InternetAddress[] iaToList = new InternetAddress().parse(toList);
message.setRecipients(RecipientType.TO, iaToList); // 收件人
}
//抄送
if (cc != null) {
String toListcc = getMailList(cc);
InternetAddress[] iaToListcc = new InternetAddress().parse(toListcc);
message.setRecipients(RecipientType.CC, iaToListcc); // 抄送人
}
//密送
if (bcc != null) {
String toListbcc = getMailList(bcc);
InternetAddress[] iaToListbcc = new InternetAddress().parse(toListbcc);
message.setRecipients(RecipientType.BCC, iaToListbcc); // 密送人
}
message.setSentDate(new Date()); // 发送日期 该日期可以随意写,你可以写上昨天的日期（效果很特别,亲测,有兴趣可以试试）,或者抽象出来形成一个参数。
message.setSubject(subject); // 主题
message.setText(content); // 内容
//显示以html格式的文本内容
messageBodyPart.setContent(content,"text/html;charset=utf-8");
multipart.addBodyPart(messageBodyPart);
//保存多个附件
if(fileList!=null){
addTach(fileList, multipart);
}
message.setContent(multipart);
// 发送邮件
Transport.send(message);
}

public void setTo(String[] to) {
this.to = to;
}

public void setCc(String[] cc) {
this.cc = cc;
}

public void setBcc(String[] bcc) {
this.bcc = bcc;
}

public void setSubject(String subject) {
this.subject = subject;
}

public void setContent(String content) {
this.content = content;
}

public void setFileList(String[] fileList) {
this.fileList = fileList;
}

private String getMailList(String[] mailArray) {
StringBuffer toList = new StringBuffer();
int length = mailArray.length;
if (mailArray != null && length < 2) {
toList.append(mailArray[0]);
} else {
for (int i = 0; i < length; i++) {
toList.append(mailArray[i]);
if (i != (length - 1)) {
toList.append(",");
}
}
}
return toList.toString();
}

//添加多个附件
public void addTach(String fileList[], Multipart multipart) throws Exception {
for (int index = 0; index < fileList.length; index++) {
MimeBodyPart mailArchieve = new MimeBodyPart();
FileDataSource fds = new FileDataSource(fileList[index]);
mailArchieve.setDataHandler(new DataHandler(fds));
mailArchieve.setFileName(MimeUtility.encodeText(fds.getName(),"UTF-8","B"));
multipart.addBodyPart(mailArchieve);
}
}

//以下是演示demo
public static void main(String args[]) {
MailTest mail = new MailTest();
mail.setSubject("java邮件");
mail.setContent("你好 这是第一个java 程序发送邮件");
//收件人 可以发给其他邮箱(163等) 下同
mail.setTo(new String[] {"xxx@qq.com"});
//抄送
// mail.setCc(new String[] {"xxx@qq.com","xxx@qq.com"});
//密送
//mail.setBcc(new String[] {"xxx@qq.com","xxx@qq.com"});
//发送附件列表 可以写绝对路径 也可以写相对路径(起点是项目根目录)
// mail.setFileList(new String[] {"D:\\aa.txt"});
//发送邮件
try {
mail.sendMessage();
System.out.println("发送邮件成功！");
} catch (Exception e) {
System.out.println("发送邮件失败！");
e.printStackTrace();
}
}
}