diff --git a/framework/logging/DbTarget.php b/framework/logging/DbTarget.php
index aa253ab..56a27bc 100644
--- a/framework/logging/DbTarget.php
+++ b/framework/logging/DbTarget.php
@@ -94,7 +94,5 @@ class DbTarget extends Target
 				':message' => $message[0],
 			))->execute();
 		}
-
-		$this->messages = array();
 	}
 }
diff --git a/framework/logging/EmailTarget.php b/framework/logging/EmailTarget.php
index f7b1fb2..0b3cc2d 100644
--- a/framework/logging/EmailTarget.php
+++ b/framework/logging/EmailTarget.php
@@ -53,8 +53,6 @@ class EmailTarget extends Target
 		foreach ($this->emails as $email) {
 			$this->sendEmail($subject, $body, $email, $this->sentFrom, $this->headers);
 		}
-
-		$this->messages = array();
 	}
 
 	/**
diff --git a/framework/logging/FileTarget.php b/framework/logging/FileTarget.php
index 3601010..276043f 100644
--- a/framework/logging/FileTarget.php
+++ b/framework/logging/FileTarget.php
@@ -79,8 +79,6 @@ class FileTarget extends Target
 			$messages[] = $this->formatMessage($message);
 		}
 		@file_put_contents($logFile, implode('', $messages), FILE_APPEND | LOCK_EX);
-
-		$this->messages = array();
 	}
 
 	/**
diff --git a/framework/logging/Logger.php b/framework/logging/Logger.php
index 187a9c8..2f0cf89 100644
--- a/framework/logging/Logger.php
+++ b/framework/logging/Logger.php
@@ -37,24 +37,16 @@ class Logger extends \yii\base\Component
 	 * Defaults to 1000, meaning the [[flush]] method will be invoked once every 1000 messages logged.
 	 * Set this property to be 0 if you don't want to flush messages until the application terminates.
 	 * This property mainly affects how much memory will be taken by the logged messages.
-	 * A smaller value means less memory, but will increase the execution time due to the overhead of [[flush]].
+	 * A smaller value means less memory, but will increase the execution time due to the overhead of [[flush()]].
 	 */
 	public $flushInterval = 1000;
 	/**
-	 * @var boolean this property will be passed as the parameter to [[flush]] when it is
-	 * called due to the [[flushInterval]] is reached. Defaults to true, meaning the flushed
-	 * messages will be exported to the actual storage medium (e.g. DB, email) defined by each
-	 * log target. If false, the flushed messages will be kept in the memory of each log target.
-	 * @see flushInterval
-	 */
-	public $autoExport = true;
-	/**
-	 * @var array logged messages. This property is mainly managed by [[log]] and [[flush]].
+	 * @var array logged messages. This property is mainly managed by [[log()]] and [[flush()]].
 	 * Each log message is of the following structure:
 	 *
 	 * ~~~
 	 * array(
-	 *   [0] => message (string)
+	 *   [0] => message (mixed)
 	 *   [1] => level (string)
 	 *   [2] => category (string)
 	 *   [3] => timestamp (float, obtained by microtime(true))
@@ -67,7 +59,7 @@ class Logger extends \yii\base\Component
 	 * Logs an error message.
 	 * An error message is typically logged when an unrecoverable error occurs
 	 * during the execution of an application.
-	 * @param string $message the message to be logged.
+	 * @param mixed $message the message to be logged.
 	 * @param string $category the category of the message.
 	 */
 	public function error($message, $category = 'application')
@@ -79,7 +71,7 @@ class Logger extends \yii\base\Component
 	 * Logs a trace message.
 	 * Trace messages are logged mainly for development purpose to see
 	 * the execution work flow of some code.
-	 * @param string $message the message to be logged.
+	 * @param mixed $message the message to be logged.
 	 * @param string $category the category of the message.
 	 */
 	public function trace($message, $category = 'application')
@@ -91,24 +83,24 @@ class Logger extends \yii\base\Component
 	 * Logs a warning message.
 	 * A warning message is typically logged when an error occurs while the execution
 	 * can still continue.
-	 * @param string $message the message to be logged.
+	 * @param mixed $message the message to be logged.
 	 * @param string $category the category of the message.
 	 */
 	public function warning($message, $category = 'application')
 	{
-		$this->log($message, self::LEVEL_TRACE, $category);
+		$this->log($message, self::LEVEL_WARNING, $category);
 	}
 
 	/**
 	 * Logs an informative message.
 	 * An informative message is typically logged by an application to keep record of
 	 * something important (e.g. an administrator logs in).
-	 * @param string $message the message to be logged.
+	 * @param mixed $message the message to be logged.
 	 * @param string $category the category of the message.
 	 */
 	public function info($message, $category = 'application')
 	{
-		$this->log($message, self::LEVEL_TRACE, $category);
+		$this->log($message, self::LEVEL_INFO, $category);
 	}
 
 	/**
@@ -119,7 +111,7 @@ class Logger extends \yii\base\Component
 	 * @param string $category the category of this log message
 	 * @see endProfile
 	 */
-	public function beginProfile($token, $category)
+	public function beginProfile($token, $category = 'application')
 	{
 		$this->log($token, self::LEVEL_PROFILE_BEGIN, $category);
 	}
@@ -131,7 +123,7 @@ class Logger extends \yii\base\Component
 	 * @param string $category the category of this log message
 	 * @see beginProfile
 	 */
-	public function endProfile($token, $category)
+	public function endProfile($token, $category = 'application')
 	{
 		$this->log($token, self::LEVEL_PROFILE_END, $category);
 	}
@@ -145,9 +137,10 @@ class Logger extends \yii\base\Component
 	 * 'trace', 'info', 'warning', 'error', 'profile'.
 	 * @param string $category the category of the message.
 	 */
-	public function log($message, $level, $category)
+	public function log($message, $level, $category = 'application')
 	{
-		if (YII_DEBUG && YII_TRACE_LEVEL > 0 && $level <= self::LEVEL_TRACE) {
+		$time = microtime(true);
+		if (YII_DEBUG && YII_TRACE_LEVEL > 0) {
 			$traces = debug_backtrace();
 			$count = 0;
 			foreach ($traces as $trace) {
@@ -159,25 +152,19 @@ class Logger extends \yii\base\Component
 				}
 			}
 		}
-
-		$this->messages[] = array($message, $level, $category, microtime(true));
+		$this->messages[] = array($message, $level, $category, $time);
 		if (count($this->messages) >= $this->flushInterval && $this->flushInterval > 0) {
-			$this->flush($this->autoExport);
+			$this->flush();
 		}
 	}
 
 	/**
 	 * Removes all recorded messages from the memory.
 	 * This method will raise a `flush` event.
-	 * The attached event handlers can process the log messages before they are removed.
-	 * @param boolean $export whether to notify log targets to export the filtered messages they have received.
 	 */
-	public function flush($export = false)
+	public function flush()
 	{
-		$this->trigger('flush', new \yii\base\Event($this, array(
-			'export' => $export,
-			'flush' => true,
-		)));
+		$this->trigger('flush');
 		$this->messages = array();
 	}
 
diff --git a/framework/logging/Router.php b/framework/logging/Router.php
index 1a84520..162402d 100644
--- a/framework/logging/Router.php
+++ b/framework/logging/Router.php
@@ -57,17 +57,10 @@ namespace yii\logging;
 class Router extends \yii\base\ApplicationComponent
 {
 	/**
-	 * @var \yii\base\Dictionary
+	 * @var Target[] list of log target objects or configurations. If the latter, target objects will
+	 * be created in [[init()]] by calling [[\Yii::createObject()]] with the corresponding object configuration.
 	 */
-	private $_targets;
-
-	/**
-	 * Constructor.
-	 */
-	public function __construct()
-	{
-		$this->_targets = new \yii\base\Dictionary;
-	}
+	public $targets = array();
 
 	/**
 	 * Initializes this application component.
@@ -78,42 +71,17 @@ class Router extends \yii\base\ApplicationComponent
 	public function init()
 	{
 		parent::init();
-		\Yii::getLogger()->on('flush', array($this, 'processMessages'));
-		if (($app = \Yii::$application) !== null) {
-			$app->on('afterRequest', array($this, 'processMessages'));
-		}
-	}
 
-	/**
-	 * Returns the log targets managed by this log router.
-	 * The keys of the dictionary are the names of the log targets.
-	 * You can use the name to access a specific log target. For example,
-	 *
-	 * ~~~
-	 * $target = $router->targets['file'];
-	 * ~~~
-	 * @return \yii\base\Dictionary the targets managed by this log router.
-	 */
-	public function getTargets()
-	{
-		return $this->_targets;
-	}
-
-	/**
-	 * Sets the log targets.
-	 * @param array $config list of log target configurations. Each array element
-	 * represents the configuration for creating a single log target. It will be
-	 * passed to [[\Yii::createObject()]] to create the target instance.
-	 */
-	public function setTargets($config)
-	{
-		foreach ($config as $name => $target) {
-			if ($target instanceof Target) {
-				$this->_targets[$name] = $target;
-			} else {
-				$this->_targets[$name] = \Yii::createObject($target);
+		foreach ($this->targets as $name => $target) {
+			if (!$target instanceof Target) {
+				$this->targets[$name] = \Yii::createObject($target);
 			}
 		}
+
+		\Yii::getLogger()->on('flush', array($this, 'processMessages'));
+		if (\Yii::$application !== null) {
+			\Yii::$application->on('afterRequest', array($this, 'processMessages'));
+		}
 	}
 
 	/**
@@ -127,11 +95,10 @@ class Router extends \yii\base\ApplicationComponent
 	public function processMessages($event)
 	{
 		$messages = \Yii::getLogger()->messages;
-		$export = !isset($event->data['export']) || $event->data['export'];
-		$final = !isset($event->data['flush']) || !$event->data['flush'];
-		foreach ($this->_targets as $target) {
+		$final = $event->name !== 'flush';
+		foreach ($this->targets as $target) {
 			if ($target->enabled) {
-				$target->processMessages($messages, $export, $final);
+				$target->processMessages($messages, $final);
 			}
 		}
 	}
diff --git a/framework/logging/Target.php b/framework/logging/Target.php
index 75cf5a4..377528b 100644
--- a/framework/logging/Target.php
+++ b/framework/logging/Target.php
@@ -16,11 +16,9 @@ namespace yii\logging;
  * to its [[levels]] and [[categories]] properties. It may also export the filtered
  * messages to specific destination defined by the target, such as emails, files.
  *
- * Level filter and category filter are combinational, i.e., only messages
- * satisfying both filter conditions will they be returned.  Additionally, you
- * may specify [[excludeCategories]]. If a message's category falls within the excluded
- * categories, it will be filtered out, even if it passes the [[levels]] and
- * [[categories]] filters.
+ * Level filter and category filter are combinatorial, i.e., only messages
+ * satisfying both filter conditions will be handled. Additionally, you
+ * may specify [[except]] to exclude messages of certain categories.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
@@ -50,7 +48,7 @@ abstract class Target extends \yii\base\Component implements \yii\base\Initable
 	 * categories starting with 'yii\db\', such as 'yii\db\dao\Connection'.
 	 * @see categories
 	 */
-	public $excludeCategories = array();
+	public $except = array();
 	/**
 	 * @var boolean whether to prefix each log message with the current session ID. Defaults to false.
 	 */
@@ -61,7 +59,7 @@ abstract class Target extends \yii\base\Component implements \yii\base\Initable
 	 */
 	public $prefixUser = false;
 	/**
-	 * @var boolean whether to log a message containing the current user name and ID. Defaults to true.
+	 * @var boolean whether to log a message containing the current user name and ID. Defaults to false.
 	 * @see \yii\web\User
 	 */
 	public $logUser = false;
@@ -72,7 +70,14 @@ abstract class Target extends \yii\base\Component implements \yii\base\Initable
 	 */
 	public $logVars = array('_GET', '_POST', '_FILES', '_COOKIE', '_SESSION', '_SERVER');
 	/**
+	 * @var boolean whether this target should export the collected messages to persistent storage
+	 * (e.g. DB, email) whenever [[processMessages()]] is called. Defaults to true. If false,
+	 * the collected messages will be stored in [[messages]] without any further processing.
+	 */
+	public $autoExport = true;
+	/**
 	 * @var array the messages that are retrieved from the logger so far by this log target.
+	 * @see autoExport
 	 */
 	public $messages = array();
 
@@ -99,17 +104,17 @@ abstract class Target extends \yii\base\Component implements \yii\base\Initable
 	 * And if requested, it will also export the filtering result to specific medium (e.g. email).
 	 * @param array $messages log messages to be processed. See [[Logger::messages]] for the structure
 	 * of each message.
-	 * @param boolean $export whether to export the processing result
 	 * @param boolean $final whether this method is called at the end of the current application
 	 */
-	public function processMessages($messages, $export, $final)
+	public function processMessages($messages, $final)
 	{
 		$messages = $this->filterMessages($messages);
 		$this->messages = array_merge($this->messages, $messages);
 
-		if ($export && !empty($this->messages)) {
+		if (!empty($this->messages) && ($this->autoExport || $final)) {
 			$this->prepareExport($final);
 			$this->exportMessages($final);
+			$this->messages = array();
 		}
 	}
 
@@ -188,7 +193,7 @@ abstract class Target extends \yii\base\Component implements \yii\base\Initable
 			}
 
 			if ($matched) {
-				foreach ($this->excludeCategories as $category) {
+				foreach ($this->except as $category) {
 					$prefix = rtrim($category, '*');
 					foreach ($messages as $i => $message) {
 						if (strpos($message[2], $prefix) === 0 && ($message[2] === $category || $prefix !== $category)) {
@@ -214,6 +219,7 @@ abstract class Target extends \yii\base\Component implements \yii\base\Initable
 	 */
 	public function formatMessage($message)
 	{
-		return @date('Y/m/d H:i:s', $message[3]) . " [{$message[1]}] [{$message[2]}] {$message[0]}\n";
+		$s = is_string($message[0]) ? $message[0] : var_export($message[0], true);
+		return date('Y/m/d H:i:s', $message[3]) . " [{$message[1]}] [{$message[2]}] $s\n";
 	}
 }