diff --git a/protocol/src/main/java/com/zfoo/protocol/collection/CollectionUtils.java b/protocol/src/main/java/com/zfoo/protocol/collection/CollectionUtils.java
index a51818d01..91cd63e81 100644
--- a/protocol/src/main/java/com/zfoo/protocol/collection/CollectionUtils.java
+++ b/protocol/src/main/java/com/zfoo/protocol/collection/CollectionUtils.java
@@ -115,6 +115,14 @@ public static int comfortableCapacity(int capacity) {
                 : (capacity < 32 ? 64 : Math.min(capacity << 1, IOUtils.BYTES_PER_MB));
     }
 
+    public static int capacity(int expectedSize) {
+        if (expectedSize < 3) {
+            return expectedSize + 1;
+        }
+        return (int) ((float) expectedSize / 0.75F + 1.0F);
+    }
+
+
     // ----------------------------------归并排序----------------------------------
 
     /**