fix: 尝试更改eml保存到本地方式解决下载出现失败问题

jeecg-boot-base-core/src/main/java/org/jeecg/common/email/EmailServiceManager.java

@@ -556,7 +556,24 @@ public class EmailServiceManager {
             final String rootPath = spectrumPathProperties.getRootPath();
             final String emlPath = spectrumPathProperties.getEmlPath();
             emlFile = new File(rootPath+emlPath+File.separator+fileName);
-            message.writeTo(new FileOutputStream(emlFile));
+//            message.writeTo(new FileOutputStream(emlFile));
+
+            int bufferSize = 1024 * 1024; // 1M
+            InputStream inputStream = message.getInputStream();
+            BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream, bufferSize);
+            // 或者使用 BufferedOutputStream
+            OutputStream outputStream = new FileOutputStream(emlFile);
+            BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(outputStream, bufferSize);
+            // 从邮件的输入流读取内容，并写入到本地文件
+            byte[] buffer = new byte[bufferSize];
+            int bytesRead;
+            while ((bytesRead = bufferedInputStream.read(buffer)) != -1) {
+                bufferedOutputStream.write(buffer, 0, bytesRead);
+            }
+
+            // 关闭流
+            bufferedInputStream.close();
+            bufferedOutputStream.close();
         } catch (MessagingException | IOException e) {
             // 下载邮件失败 抛出自定义邮件下载异常
             status = EmailLogManager.STATUS_ERROR;