添加方法first

@@ -63,11 +63,27 @@ class Messages
      * 判断是否有错误信息
      * @return bool
      */
-    public function has()
+    public function has($key = null)
     {
+        if ($key == null) {
+            return count($this->messages) > 0;
+        }
         return isset($this->messages[$key]);
     }
 
+    /**
+     * 第一个错误
+     * @param $key
+     * @return array
+     */
+    public function first($key)
+    {
+        if (isset($this->messages[$key])) {
+            return $this->messages[$key][0];
+        }
+        return '';
+    }
+
     public function getMessages($key, $type = null)
     {
         if (isset($this->customMessages[$key])) {