email邮件(带附件，模拟文件上传，跨服务器)发送核心代码 Couldn't connect to host, port: smtp.163.com, 25; timeout -1;

邮件(带附件，模拟文件上传，跨服务器)发送核心代码
1.测试邮件发送附件接口

/**
     * 测试邮件发送附件
     * @param multipartFile
     * @return
     */
    @RequestMapping("/upload")
    public String uploadFile(@RequestParam("uploadFile") MultipartFile multipartFile){
       try {
           //邮件发送
           File file = MultipartFileToFile(multipartFile);
           //调用邮件统一接口 发送邮件
           //方案1：将file转base64来传输，同时记录文件名称
           /**
           * FileEntity fe = new FileEntity();
            *fe.setFileName(file.getName());
            *fe.setFileBase64String(FileUtil.fileToBase64(file));
           **/
           //方案2: 将文件上传到临时存放点，比如：阿里云的OSS服务器，直接通过接口来传输file对象不可以跨服务器，在本机服务器是可以的。

           //@Async邮件发送采用异步的方式来发送
           //将邮件的内容等json串做md5,可以作为唯一key，避免重复邮件的重复发送
           //数据先落库，等异步处理之后，更新唯一key的成功或失败的状态
           //邮件公用接口，记录发送的来源方，项目名称，业务线记录等。

           return "邮件发送成功";
       }catch (Exception e) {
           e.printStackTrace();
           return "邮件发送失败";
       }
    }

2.文件工具类

/**
    *MultipartFile 转file工具类
    **/
    public static File MultipartFileToFile(MultipartFile multipartFile) {

        File file = null;
        //判断是否为null
        if (multipartFile.equals("") || multipartFile.getSize() <= 0) {
            return file;
        }
        //MultipartFile转换为File
        InputStream ins = null;
        OutputStream os = null;
        try {
            ins = multipartFile.getInputStream();
            file = new File(multipartFile.getOriginalFilename());
            os = new FileOutputStream(file);
            int bytesRead = 0;
            byte[] buffer = new byte[8192];
            while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if(os != null){
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(ins != null){
                try {
                    ins.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return file;
    }

import java.io.*;
import java.util.Base64;

/**
 * 文件工具类
 */
public class FileUtil {
    /**
     * 将文件转base64字符串
     * @param path
     * @return
     */
    public static  String fileToBase64(String path) {
        String base64 = null;
        InputStream in = null;
        try {
            File file = new File(path);
            in = new FileInputStream(file);
            byte[] bytes=new byte[(int)file.length()];
            in.read(bytes);
            base64 = Base64.getEncoder().encodeToString(bytes);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return base64;
    }

    /**
     * 将文件转base64字符串
     * @param file
     * @return
     */
    public static  String fileToBase64(File file) {
        if(file == null){
            return null;
        }
        String base64 = null;
        InputStream in = null;
        try {
//            File file = new File(path);
            in = new FileInputStream(file);
            byte[] bytes=new byte[(int)file.length()];
            in.read(bytes);
            base64 = Base64.getEncoder().encodeToString(bytes);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return base64;
    }

    /**
     * BASE64解码成File文件
     * @param destPath
     * @param base64
     * @param fileName
     */
    public static File base64ToFile(String destPath,String base64, String fileName) {
        File file = null;
        //创建文件目录
        String filePath=destPath;
        File  dir=new File(filePath);
        if (!dir.exists() && !dir.isDirectory()) {
            dir.mkdirs();
        }
        BufferedOutputStream bos = null;
        java.io.FileOutputStream fos = null;
        try {
            byte[] bytes = Base64.getDecoder().decode(base64);
            file=new File(filePath+"/"+fileName);
            fos = new java.io.FileOutputStream(file);
            bos = new BufferedOutputStream(fos);
            bos.write(bytes);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (bos != null) {
                try {
                    bos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return file;
    }

}

3.实体类

//FileEntity对象
public class FileEntity {
    private String fileBase64String;
    private String fileName;

    public String getFileBase64String() {
        return fileBase64String;
    }

    public void setFileBase64String(String fileBase64String) {
        this.fileBase64String = fileBase64String;
    }

    public String getFileName() {
        return fileName;
    }

    public void setFileName(String fileName) {
        this.fileName = fileName;
    }
}

4.邮件发送service类

import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

//邮件发送带附件的工具类
@Service
public class EmailMultiService {
    private static Logger logger = LoggerFactory.getLogger(EmailMultiService.class);

    public static MailAuthenticator authenticator;
    private MimeMessage message;
    private Session session;
    private Transport transport;
    private Properties properties = new Properties();

    //apollo配置
    @Value("${apollo.server.host}")
    private String mailHost = null;
    @Value("${apollo.from.addr}")
    private String sender_username = null;
    @Value("${apollo.email.password}")
    private String sender_password = null;

    /**
     * 构造方法
     */
    public EmailMultiService() {
        super();
    }

    /**
     * 主方法
     */
    public String  sendEmail(String[] receivers,String[] receiversCC,String title, String content,List<FileEntity> fileList,String md5) {
        try {
            // 初始化smtp发送邮件所需参数
            initSmtpParams();
            // 发送邮件
            doSendHtmlEmail(receivers, receiversCC, title, content, fileList,md5);
        } catch (Exception e) {
            logger.error("sendEmail multi异常:",e);
            return "";
        }
        return "success";
    }

    /**
     * 初始化smtp发送邮件所需参数
     */
    private boolean initSmtpParams() {
        properties.put("mail.smtp.host", mailHost);// mail.envisioncitrix.com
        properties.put("mail.smtp.auth", "true");
        properties.put("mail.transport.protocol", "smtp");
        //端口 重要，默认是25端口  　Couldn't connect to host, port: smtp.163.com, 25; timeout -1;
        properties.put("mail.smtp.port", "465");
        properties.put("mail.smtp.starttls.enable", "true");
        properties.put("mail.smtp.ssl.checkserveridentity", "false");
        properties.put("mail.smtp.ssl.trust", mailHost);
        //重要
        properties.setProperty("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

        authenticator = new MailAuthenticator(sender_username, sender_password);
        session = Session.getInstance(properties, authenticator);
        session.setDebug(false);// 开启后有调试信息
        message = new MimeMessage(session);

        return true;
    }

    /**
     * 发送邮件
     */
    private boolean doSendHtmlEmail(String[] toEmial,String[] toCcEmial,String title, String htmlContent, List<FileEntity> fileList,String md5) {
        try {
            // 发件人
            InternetAddress from = new InternetAddress(sender_username);
            message.setFrom(from);

            // 收件人(多个) 数组方式，会覆盖掉，最终是发送最后一个邮箱地址
            //for (String sendTo : toEmial) {
             //   message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(sendTo));
            //}

　　　　　　　InternetAddress[] address = new InternetAddress[toEmial.length];
            for (int i = 0; i < toEmial.length; i++) {
                String sendTo = toEmial[i];
                InternetAddress addr = new InternetAddress(sendTo);
                address[i] = addr;
            }

            message.setRecipients(Message.RecipientType.TO, address);

// 设置抄送：抄送地址必须满足标准email地址格式，否则报错
            //可选
            if(toCcEmial != null && toCcEmial.length > 0) {
                //for (String copy : toCcEmial) {
                //    message.setRecipients(Message.RecipientType.CC, InternetAddress.parse(copy));
                //}

　　　　　　　　　　InternetAddress[] addressCC = new InternetAddress[toCcEmial.length];
                for (int i = 0; i < toCcEmial.length; i++) {
                    String sendTo = toCcEmial[i];
                    InternetAddress addr = new InternetAddress(sendTo);
                    addressCC[i] = addr;
                }

　　　　　　　　　　　　message.setRecipients(Message.RecipientType.CC, addressCC);

            }

            // 邮件主题
            message.setSubject(title);

            // 添加邮件的各个部分内容，包括文本内容和附件
            Multipart multipart = new MimeMultipart();

            // 添加邮件正文
            BodyPart contentPart = new MimeBodyPart();
            contentPart.setContent(htmlContent, "text/html;charset=UTF-8");
            multipart.addBodyPart(contentPart);

            // 遍历添加附件
            if (fileList != null && fileList.size() > 0) {
                //转换文件操作
                List<File> files = new ArrayList<>();
                //按上传日期来上传目录 文件路径
                Long today = Long.parseLong(DateFormatUtils.format(new Date(), "yyyyMMdd").trim());
                String destPath  = "/usr/local/email/"+ String.valueOf(today) +"/" + md5 + "/";
                for (FileEntity fileEntity : fileList) {
                    File f = FileUtil.base64ToFile(destPath,fileEntity.getFileBase64String(),fileEntity.getFileName());
                    files.add(f);
                }

                //封装成附件的方式
                for (File file : files) {
                    if(file != null) {
                        BodyPart attachmentBodyPart = new MimeBodyPart();
                        DataSource source = new FileDataSource(file);
                        attachmentBodyPart.setDataHandler(new DataHandler(source));
                        attachmentBodyPart.setFileName(file.getName());
                        multipart.addBodyPart(attachmentBodyPart);
                    }
                }
            }

            // 将多媒体对象放到message中
            message.setContent(multipart);

            // 保存邮件
            message.saveChanges();

            // SMTP验证，就是你用来发邮件的邮箱用户名密码
            transport = session.getTransport("smtp");
            transport.connect(mailHost, sender_username, sender_password);

            // 发送邮件
            transport.sendMessage(message, message.getAllRecipients());

            logger.info(title + " Email send success!");
        } catch (Exception e) {
            logger.error("发送附件邮件异常:",e);
        } finally {
            if (transport != null) {
                try {
                    transport.close();
                } catch (MessagingException e) {
                    logger.error("finally发送附件邮件异常:",e);
                }
            }
        }
        return true;
    }

}

//普通邮件发送，不带附件的方式
public String sendEmail(String[] toEmial, String[] toCcEmial, String subject, String content) {
        try {
            HtmlEmail simpleEmail = new HtmlEmail();
            simpleEmail.setHostName(mailHost);
            simpleEmail.setAuthentication(sender_username, sender_password);
            simpleEmail.setFrom(sender_username, sender_username);
            simpleEmail.addTo(toEmial);
            if (toCcEmial != null) {
                simpleEmail.addCc(toCcEmial);
            }
            simpleEmail.setSubject(subject);
            simpleEmail.setMsg(content);
            //add
            simpleEmail.setSSLOnConnect(true);
            simpleEmail.setCharset(StandardCharsets.UTF_8.name());
            return simpleEmail.send();
        } catch (Exception e) {
            logger.error("发送邮件异常：", e);
        }
        return null;
    }