fix(customer): NPE of article detail

Author: HackyleShawe

blog-customer/src/main/java/com/hackyle/blog/customer/module/article/service/impl/ArticleServiceImpl.java

@@ -137,7 +137,8 @@ public ArticleVo get(String articleCode) {
 
         ArticleVo articleVo = BeanCopyUtils.copy(articleEntity, ArticleVo.class);
         articleVo.setUrl(articlePathPrefix + articleEntity.getPath());
-        articleVo.setUpdateTime(articleEntity.getUpdateTime().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
+        LocalDateTime updateTime = articleEntity.getUpdateTime() == null ? articleEntity.getCreateTime() : articleEntity.getUpdateTime();
+        articleVo.setUpdateTime(updateTime.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
 
         List<CategoryDto> categoryDtos = categoryService.getByArticleIds(Collections.singletonList(articleEntity.getId()));
         if(CollectionUtil.isNotEmpty(categoryDtos)) {