feat: user related logic refactor

src/main/java/xin/merlin/myplayerbackend/service/MailService.java

@@ -33,4 +33,19 @@ public class MailService {
             throw new RuntimeException(e);
         }
     }
+
+    public Boolean sendTextMail(String receiver, String text){
+        try {
+            SimpleMailMessage message = new SimpleMailMessage();
+            message.setFrom(mail);
+            message.setTo(receiver);
+            message.setSubject("Welcome to use Merlin`s product");
+            message.setText("欢迎使用Merlin.xin产品！ \n"+text);
+            mailSender.send(message);
+            return true;
+        } catch (MailException e) {
+            log.error("e: ", e);
+            throw new RuntimeException(e);
+        }
+    }
 }