diff --git a/library/src/androidTest/java/com/qiniu/android/EtagTest.java b/library/src/androidTest/java/com/qiniu/android/EtagTest.java
index 84b819dce..0dc4fa8d2 100644
--- a/library/src/androidTest/java/com/qiniu/android/EtagTest.java
+++ b/library/src/androidTest/java/com/qiniu/android/EtagTest.java
@@ -3,6 +3,7 @@
 import android.test.AndroidTestCase;
 
 import com.qiniu.android.common.Constants;
+import com.qiniu.android.storage.Configuration;
 import com.qiniu.android.utils.Etag;
 
 import junit.framework.Assert;
@@ -40,6 +41,13 @@ public void testFile() throws IOException {
         f = TempFile.createFile(9 * 1024);
         Assert.assertEquals("ljgVjMtyMsOgIySv79U8Qz4TrUO4", Etag.file(f));
         TempFile.remove(f);
+    }
 
+    public void testLongToInt() {
+        long len = 2323435710l;
+        int b = (int) ((len + Configuration.BLOCK_SIZE - 1) / Configuration.BLOCK_SIZE);
+        Assert.assertEquals("不应该溢出", 554, b);
+        int a = (int) (len + Configuration.BLOCK_SIZE - 1) / Configuration.BLOCK_SIZE;
+        Assert.assertNotSame("预计会溢出", 554, a);
     }
 }
diff --git a/library/src/main/java/com/qiniu/android/utils/Etag.java b/library/src/main/java/com/qiniu/android/utils/Etag.java
index d796fee76..dfe9eb26a 100644
--- a/library/src/main/java/com/qiniu/android/utils/Etag.java
+++ b/library/src/main/java/com/qiniu/android/utils/Etag.java
@@ -81,7 +81,7 @@ public static String stream(InputStream in, long len) throws IOException {
             return "Fto5o-5ea0sNMlW_75VgGJCv2AcJ";
         }
         byte[] buffer = new byte[64 * 1024];
-        byte[][] blocks = new byte[(int) (len + Configuration.BLOCK_SIZE - 1) / Configuration.BLOCK_SIZE][];
+        byte[][] blocks = new byte[(int) ((len + Configuration.BLOCK_SIZE - 1) / Configuration.BLOCK_SIZE)][];
         for (int i = 0; i < blocks.length; i++) {
             long left = len - (long) Configuration.BLOCK_SIZE * i;
             long read = left > Configuration.BLOCK_SIZE ? Configuration.BLOCK_SIZE : left;