更新 '_posts/常用的代码块.md'

_posts/常用的代码块.md

@@ -25,4 +25,12 @@ categories: 运维工具
                 .forEachOrdered(e -> result.put(e.getKey(), e.getValue()));
         return result;
     }
-```
+```
+
+### list 对象根据某个字段分组
+
+```java
+
+Map<Object,List<Object>> map = demoList.stream().collect(Collectors.groupingBy(Object::getAttr));
+
+```