isNumber update

src/main/java/com/alibaba/druid/util/StringUtils.java

@@ -119,18 +119,4 @@ public class StringUtils {
         }
         return h;
     }
-
-    public static boolean isNumeric(final CharSequence cs) {
-        if (isEmpty(cs)) {
-            return false;
-        }
-        final int sz = cs.length();
-        for (int i = 0; i < sz; i++) {
-            if (!Character.isDigit(cs.charAt(i))) {
-                return false;
-            }
-        }
-        return true;
-    }
-
 }