1、设置系统值

System.setProperty(“mail.mime.splitlongparameters”, “false”);

2、 在创建对象的时候定义编码格式(utf-8)：

MimeMessageHelper helper = new MimeMessageHelper(mes, true, “utf-8”);

3、 其次，在添加附件的时候，附件名是需要定义编码的

helper.addAttachment(MimeUtility.encodeWord(附件名,“utf-8”,“B”), 你的附件对象);
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版权声明：本文为CSDN博主「往事不堪回首…」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/qq3892997/article/details/126013828

//生成的数据通过excel附件的方式，进行发送。public void sendMail(String mailFrom, String mailTo, String title, String content, File file) throws Exception {System.setProperty("mail.mime.splitlongparameters", "false");//1.设置系统值 ---处理文件名乱码MimeMessage mimeMessage = mailSender.createMimeMessage();MimeMessageHelper msg = new MimeMessageHelper(mimeMessage, true, "utf-8");//2.在创建对象的时候定义编码格式(utf-8)msg.addAttachment(MimeUtility.encodeWord(excelName,"utf-8","B"), file); //3.在添加附件的时候，附件名是需要定义编码的 ---以上3条都得有，否则文件名乱码msg.setFrom(mailFrom);msg.setTo(mailTo);msg.setSubject(title);msg.setText(content, true);mailSender.send(mimeMessage);}

工具类

@Component
@Slf4j
/*** 发送邮件工具类* @author ZMH* @date 7/7/2023 2:03 下午*/
public class EmailUtils {@Autowiredprivate JavaMailSender javaMailSender;/*** 发送纯文本邮件* @author ZMH* @date 7/7/2023 10:37 上午* @param subject 邮件主题* @param text 邮件内容* @param targetEmail 目标邮件地址* @param sourceEmail 源邮件地址* @return void*/public void sendTextEmail (String subject,String text,String targetEmail,String sourceEmail ){SimpleMailMessage mailMessage = new SimpleMailMessage();mailMessage.setSubject(subject);//主题mailMessage.setText(text);//内容if (StringUtils.isNotBlank(targetEmail) && targetEmail.split(",").length>1){mailMessage.setTo(targetEmail.split(","));//多个号码发送，该发送会将目标邮件分组发送}else {mailMessage.setTo(targetEmail);}mailMessage.setFrom(sourceEmail);javaMailSender.send(mailMessage);}/*** 发送文本邮件和附件* @author ZMH* @date 7/7/2023 2:01 下午* @param subject 主题* @param text 文本内容* @param targetEmail 目标邮件* @param sourceEmail 源邮件* @param annexList 附件List* @param anneNameList 附件名称List* @return void*/public void sendTextAndAnnexEmail(String subject,String text,String targetEmail,String sourceEmail,String personal, List<File> annexList,List<String> anneNameList ) throws MessagingException {sendSeniorEmail(subject,null,false,text,targetEmail,sourceEmail,personal,annexList,anneNameList);}/*** 发送邮件根据HTML模本文件* @author ZMH* @date 7/7/2023 11:16 上午* @param subject 主题* @param content 内容* @param targetEmail 目标邮件* @param sourceEmail 源邮件* @return void*/public void sendHTMLEmail(String subject,String content,String targetEmail,String sourceEmail,String personal) throws MessagingException {sendSeniorEmail(subject,content,true,"",targetEmail,sourceEmail,personal,null,null);}/*** 发送模版文件并包含附件* @author ZMH* @date 7/7/2023 11:20 上午* @param subject 主题* @param content 内容* @param targetEmail 目标邮件* @param sourceEmail 源邮件* @param annexList 附件* @param annexNameList 附件名称* @return void*/public void sendHTMLAndAnnexEmail(String subject,String content,String targetEmail,String sourceEmail,String personal,List<File> annexList,List<String> annexNameList) throws MessagingException {sendSeniorEmail(subject,content,true,"",targetEmail,sourceEmail,personal,annexList,annexNameList);}/*** 发送高级邮件* @author ZMH* @date 7/7/2023 11:26 上午* @param subject 主题* @param concent content* @param targetEmail 目标邮箱* @param sourceEmail 源邮箱* @param annexList 附件* @param annexNameList 附件名称* @return void*/private void sendSeniorEmail(String subject, String concent, Boolean isHtml, String txet, String targetEmail,String sourceEmail,String personal, List<File> annexList, List<String> annexNameList) throws MessagingException{System.setProperty("mail.mime.splitlongparameters", "false");//1.设置系统值 ---处理文件名乱码MimeMessage message = javaMailSender.createMimeMessage();MimeMessageHelper helper = new MimeMessageHelper(message,true,"utf-8");helper.setSubject(subject);//邮件主题try {helper.setFrom(sourceEmail,personal);} catch (UnsupportedEncodingException e) {e.printStackTrace();}if (StringUtils.isNotBlank(targetEmail) && targetEmail.split(",").length>1){helper.setTo(targetEmail.split(","));//多个号码发送，该发送为分组发送}else {helper.setTo(targetEmail);}if (isHtml) {//String absolutePath = htmlFile.getAbsolutePath();//String htmlModel = FileUtil.getStringByFile(absolutePath);concent = "<!DOCTYPE html>\n" +"<html lang=\"en\">\n" +"<head>\n" +"    <meta charset=\"UTF-8\">\n" +"    <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">\n" +"    <title></title>\n" +"</head>\n" +"<body>\n" +"  <div>" + concent + "</div>\n" +"</body>\n" +"</html>";helper.setText(concent,true);}else {helper.setText(txet,false);}helper.setSentDate(new Date());//邮件发送时间if (!CollectionUtils.isEmpty(annexList)){if (CollectionUtils.isEmpty(annexNameList)){for (File file : annexList) {annexNameList.add(file.getName());}}else {if (annexList.size()!= annexNameList.size()){throw new MessagingException("附件名称和附件条次不一致");}}try {for (int i = 0; i < annexList.size(); i++) {helper.addAttachment(MimeUtility.encodeWord(annexNameList.get(i), "utf-8", "B"), annexList.get(i));}} catch (UnsupportedEncodingException e) {e.printStackTrace();}}javaMailSender.send(message);}}

yml配置文件增加

spring:mail:username: 邮箱号码password: 授权码host: smtp.qq.comport: 465properties:mail:smtp:auth: truesocketFactory:class: javax.net.ssl.SSLSocketFactorystarttls:enable: truessl:enable: true

pom.xml 增加

	  <!-- SpringEmail --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-mail</artifactId></dependency>