diff --git a/lib/emulator/logging.rb b/lib/emulator/logging.rb
index 3949071..5b90b3c 100644
--- a/lib/emulator/logging.rb
+++ b/lib/emulator/logging.rb
@@ -16,7 +16,7 @@ module OssEmulator
   #   Log.fatal("something", 'red')
   class Log
 
-    LOG_DEFAULT_DIR = "../log"
+    LOG_DEFAULT_DIR = "log"
     LOG_DEFAULT_FILE = "#{LOG_DEFAULT_DIR}/emulator.log"
     LOG_TEST_FILE = "#{LOG_DEFAULT_DIR}/test.log"
     LOG_ALIYUN_SDK_FILE = "#{LOG_DEFAULT_DIR}/aliyun_sdk.log"
diff --git a/lib/emulator/server.rb b/lib/emulator/server.rb
index a05d8e7..83b38ee 100644
--- a/lib/emulator/server.rb
+++ b/lib/emulator/server.rb
@@ -193,7 +193,7 @@ def initialize(address, port, hostname, ssl_cert_path, ssl_key_path, extra_optio
           )
         rescue
           webrick_config.merge!(
-            :Logger => WEBrick::Log.new(nil),
+            :Logger => WEBrick::Log.new(File.open(File::NULL, 'w')),
             :AccessLog => []
           )
         end
diff --git a/lib/emulator/util.rb b/lib/emulator/util.rb
index 9f8c021..7bcbd9c 100644
--- a/lib/emulator/util.rb
+++ b/lib/emulator/util.rb
@@ -60,24 +60,22 @@ def self.valid_object_name(name)
     def self.get_bucket_list_objects(lbr, req)
       marker = req.query["marker"] ? req.query["marker"].to_s : nil
       marker_found = (marker==nil || marker=="") ? true : false
-      prefix = req.query["prefix"] ? req.query["prefix"].to_s : nil
-      prefix = nil if prefix==""
+      prefix = req.query["prefix"] ? req.query["prefix"].to_s : ""
+
       max_keys = req.query["max-keys"] ? req.query["max-keys"].to_i : 100
       max_keys = max_keys>1000 ? 1000 : max_keys
       delimiter = req.query["delimiter"] ? req.query["delimiter"].to_s : nil
       delimiter = nil if delimiter==""
 
       if delimiter
-        if prefix
-          base_prefix = prefix
-        else
-          base_prefix = ""
-        end
+        base_prefix = prefix
         prefix_offset = base_prefix.length
       end
 
       bucket_path = File.join(Config.store, req.bucket, '/')
-      find_root_folder = bucket_path 
+
+
+      find_root_folder = File.join(Config.store, req.bucket, prefix, '/')
       object_list = []
       common_prefix_list = []
       is_truncated = false