diff --git a/README.md b/README.md
index 505c39a..50da901 100644
--- a/README.md
+++ b/README.md
@@ -24,8 +24,9 @@
   - 使用其它 Webserver，可以自行查询如何将 .htaccess 规则转换为你所使用的网站配置并写进你的网站配置当中
 - PHP 版本 8.0 以上
   （旧版可能可以使用，但未经完全测试）
-  - PHP 模块 `xml` (旧版可能叫做 `dom`)
+  - PHP 模块 `xml` (也可能叫做 `dom`)
   - PHP 模块 `mbstring`
+  - PHP 模块 `fileinfo`
   - composer 工具以安装项目依赖
   - 在 php.ini 中设置 `display_errors` 以及 `display_startup_errors` 为 `Off` (或者关闭 `E_WARNING` 及以下 log) <small>(这是由于最开始写代码极不上心导致很多地方都会有可能报出 warn，输出在屏幕上会导致很糟糕的使用体验)</small>
 
diff --git a/composer.json b/composer.json
index 0aa877d..9645576 100644
--- a/composer.json
+++ b/composer.json
@@ -11,10 +11,17 @@
 			"email": "email@example.com"
 		}
 	],
+	"autoload": {
+		"psr-4": {
+			"SukWs\\Bookshelf\\": "src"
+		}
+	},
 	"require": {
 		"php": ">=8.0",
 		"ext-xml": "*",
+		"ext-dom": "*",
 		"ext-mbstring": "*",
+		"ext-fileinfo": "*",
 		"league/commonmark": ">=2.3.8"
 	}
 }
\ No newline at end of file
diff --git a/constant.php b/constant.php
index b8983f8..d4f6824 100644
--- a/constant.php
+++ b/constant.php
@@ -2,6 +2,6 @@
 
 const APP_NAME = "ph-Bookshelf";
 
-const VERSION = "0.3.0.15";
+const VERSION = "0.3.1";
 const CHANNEL = "suk-ws";
 const BRANCH = "master";
diff --git a/index.php b/index.php
index c24b53f..c036fe4 100644
--- a/index.php
+++ b/index.php
@@ -1,13 +1,12 @@
 <?php
 
-require_once "./vendor/autoload.php";
-
-require_once "./src/Data/SiteMeta.php";
-require_once "./src/Data/PageMeta.php";
-require_once "./src/Utils/PageParse.php";
-require_once "./src/Utils/RequestNotExistException.php";
-
+require "./constant.php";
+require "./vendor/autoload.php";
 
+use SukWs\Bookshelf\Data\PageMeta;
+use SukWs\Bookshelf\Data\SiteMeta;
+use SukWs\Bookshelf\Utils\PageParse;
+use SukWs\Bookshelf\Utils\RequestNotExistException;
 
 try {
 	
@@ -40,12 +39,12 @@ try {
 				if ($tmp == null) throw new RequestNotExistException("Page required \"$uri[1]\" not found on book \"$uri[0]\"!");
 				PageMeta::$page = $tmp;
 			} else {
-				PageMeta::$page = PageMeta::$book->getChilds()->getChilds()[0];
+				PageMeta::$page = PageMeta::$book->getChilds()->getChildren()[0];
 			}
 		} else {
 			// 主页面
 			PageMeta::$book = SiteMeta::getBookshelf()->getRootBook();
-			PageMeta::$page = PageMeta::$book->getChilds()->getChilds()[0];
+			PageMeta::$page = PageMeta::$book->getChilds()->getChildren()[0];
 			PageMeta::$isMainPage = true;
 		}
 		
diff --git a/src/Data/PageMeta.php b/src/Data/PageMeta.php
index 70fdf4c..c1bf95f 100644
--- a/src/Data/PageMeta.php
+++ b/src/Data/PageMeta.php
@@ -1,8 +1,9 @@
 <?php
 
-require_once "./src/Data/SiteMeta.php";
-require_once "./src/Element/BookContent/BookContented.php";
-require_once "./src/Element/BookContent/Page.php";
+namespace SukWs\Bookshelf\Data;
+
+use SukWs\Bookshelf\Element\BookContent\BookContented;
+use SukWs\Bookshelf\Element\BookContent\Page;
 
 class PageMeta {
 	
diff --git a/src/Data/SiteMeta.php b/src/Data/SiteMeta.php
index 478f71d..a5425fd 100644
--- a/src/Data/SiteMeta.php
+++ b/src/Data/SiteMeta.php
@@ -1,8 +1,9 @@
 <?php
 
-require_once "./src/Data/PageMeta.php";
-require_once "./src/Element/Bookshelf.php";
-require_once "./constant.php";
+namespace SukWs\Bookshelf\Data;
+
+use Exception;
+use SukWs\Bookshelf\Element\Bookshelf;
 
 class SiteMeta {
 	
@@ -19,7 +20,7 @@ class SiteMeta {
 	/**
 	 * @throws Exception
 	 */
-	public static function load () {
+	public static function load (): void {
 		self::$BOOKSHELF = Bookshelf::parseString(file_get_contents("./data/bookshelf.xml"));
 	}
 	
diff --git a/src/Element/Book.php b/src/Element/Book.php
index da50a7a..f4d9847 100644
--- a/src/Element/Book.php
+++ b/src/Element/Book.php
@@ -1,8 +1,11 @@
 <?php
 
-require_once "./src/Data/PageMeta.php";
-require_once "./src/Element/BookCollection.php";
-require_once "./src/Element/BookContent/BookContented.php";
+namespace SukWs\Bookshelf\Element;
+
+use SukWs\Bookshelf\Data\PageMeta;
+use DOMNode;
+use SukWs\Bookshelf\Element\BookContent\BookContented;
+use Exception;
 
 class Book {
 	
@@ -50,7 +53,7 @@ class Book {
 	/**
 	 * @return BookCollection|null
 	 */
-	public function getParent (): BookCollection {
+	public function getParent (): ?BookCollection {
 		return $this->parent;
 	}
 	
diff --git a/src/Element/BookCollection.php b/src/Element/BookCollection.php
index 788082e..0da485f 100644
--- a/src/Element/BookCollection.php
+++ b/src/Element/BookCollection.php
@@ -1,7 +1,10 @@
 <?php
 
-require_once "./src/Data/PageMeta.php";
-require_once "./src/Element/Book.php";
+namespace SukWs\Bookshelf\Element;
+
+use SukWs\Bookshelf\Data\PageMeta;
+use DOMNode;
+use Exception;
 
 class BookCollection {
 	
@@ -39,15 +42,16 @@ class BookCollection {
 		for ($child = $root->firstChild; $child != null; $child = $child->nextSibling) {
 			switch ($child->nodeName) {
 				case "Book":
-					array_push($node->array, Book::parse($child, $node));
+					$node->array[] = Book::parse($child, $node);
 					break;
 				case "Collection":
-					array_push($node->array, BookCollection::parse($child, $node));
+					$node->array[] = BookCollection::parse($child, $node);
 					break;
 				case "#comment":
 					break;
 				case "#text":
 					if (empty(trim($child->nodeValue))) break;
+					throw new Exception("Unsupported element type \"$child->nodeName\" in BookCollection named \"$name\"");
 				default:
 					throw new Exception("Unsupported element type \"$child->nodeName\" in BookCollection named \"$name\"");
 			}
@@ -69,7 +73,7 @@ class BookCollection {
 	/**
 	 * @return BookCollection|null
 	 */
-	public function getParent (): BookCollection {
+	public function getParent (): ?BookCollection {
 		return $this->parent;
 	}
 	
diff --git a/src/Element/BookContent/BookContented.php b/src/Element/BookContent/BookContented.php
index 412cbab..91da22b 100644
--- a/src/Element/BookContent/BookContented.php
+++ b/src/Element/BookContent/BookContented.php
@@ -1,8 +1,11 @@
 <?php
 
-require_once "./src/Element/Book.php";
-require_once "./src/Element/Bookshelf.php";
-require_once "./src/Element/BookContent/Chapter.php";
+namespace SukWs\Bookshelf\Element\BookContent;
+
+use DOMDocument;
+use DOMNode;
+use SukWs\Bookshelf\Element\Bookshelf;
+use Exception;
 
 class BookContented {
 	
diff --git a/src/Element/BookContent/Chapter.php b/src/Element/BookContent/Chapter.php
index 43036b7..10171cd 100644
--- a/src/Element/BookContent/Chapter.php
+++ b/src/Element/BookContent/Chapter.php
@@ -1,19 +1,23 @@
 <?php
 
-require_once "./src/Element/BookContent/Page.php";
+namespace SukWs\Bookshelf\Element\BookContent;
+
+use SukWs\Bookshelf\Data\PageMeta;
+use DOMNode;
+use Exception;
 
 class Chapter {
 	
 	private string $name;
 	
 	/** @var Chapter[]|Page[] */
-	private array $childs;
+	private array $children;
 	
 	private ?Chapter $parent;
 	
 	private function __construct (string $name, array $array, ?Chapter $parent) {
 		$this->name = $name;
-		$this->childs = $array;
+		$this->children = $array;
 		$this->parent = $parent;
 	}
 	
@@ -32,15 +36,16 @@ class Chapter {
 		for ($child = $xmlData->firstChild;$child != null ; $child = $child->nextSibling) {
 			switch ($child->nodeName) {
 				case "Page":
-					array_push($node->childs, Page::parse($child, $node));
+					$node->children[] = Page::parse($child, $node);
 					break;
 				case "Chapter":
-					array_push($node->childs, self::parse($child, $node));
+					$node->children[] = self::parse($child, $node);
 					break;
 				case "#comment":
 					break;
 				case "#text":
 					if (empty(trim($child->nodeValue))) break;
+					throw new Exception("Unsupported element type \"$child->nodeName\" in Chapter \"$node->name\"");
 				default:
 					throw new Exception("Unsupported element type \"$child->nodeName\" in Chapter \"$node->name\"");
 			}
@@ -55,14 +60,14 @@ class Chapter {
 	/**
 	 * @return Chapter[]|Page[]
 	 */
-	public function getChilds (): array {
-		return $this->childs;
+	public function getChildren (): array {
+		return $this->children;
 	}
 	
 	/**
 	 * @return Chapter|null
 	 */
-	public function getParent (): Chapter {
+	public function getParent (): ?Chapter {
 		return $this->parent;
 	}
 	
@@ -76,7 +81,7 @@ class Chapter {
 			$this->getPage(PageMeta::$page->getId())==null?"":" active",
 			$this->name
 		);
-		foreach ($this->childs as $node) {
+		foreach ($this->children as $node) {
 			$str .= $node->getSummaryHtml();
 		}
 		if ($this->parent != null) $str .= "</div></div>";
@@ -85,7 +90,7 @@ class Chapter {
 	
 	public function getPage (string $id): ?Page {
 		
-		foreach ($this->childs as $node) {
+		foreach ($this->children as $node) {
 			if ($node instanceof Page && $node->getId() == $id)
 				return $node;
 			else if ($node instanceof Chapter) {
diff --git a/src/Element/BookContent/Page.php b/src/Element/BookContent/Page.php
index e59621a..a900875 100644
--- a/src/Element/BookContent/Page.php
+++ b/src/Element/BookContent/Page.php
@@ -1,8 +1,11 @@
 <?php
 
-require_once "./src/Data/PageMeta.php";
-require_once "./src/Element/Bookshelf.php";
-require_once "./src/Element/BookContent/Chapter.php";
+namespace SukWs\Bookshelf\Element\BookContent;
+
+use SukWs\Bookshelf\Data\PageMeta;
+use DOMNode;
+use SukWs\Bookshelf\Element\Bookshelf;
+use Exception;
 
 class Page {
 	
@@ -39,7 +42,7 @@ class Page {
 			Bookshelf::parseConfigurationAttr($xmlData->attributes, $node->configurations, array("name", "id"));
 		} else
 			throw new Exception("Book xml data missing attributes");
-		for ($child = $xmlData->firstChild;$child != null ; $child = $child->nextSibling) {
+		for ($child = $xmlData->firstChild; $child != null; $child = $child->nextSibling) {
 			switch ($child->nodeName) {
 				case "#text":
 				default:
diff --git a/src/Element/Bookshelf.php b/src/Element/Bookshelf.php
index 5bf3f60..4ce01e3 100644
--- a/src/Element/Bookshelf.php
+++ b/src/Element/Bookshelf.php
@@ -1,8 +1,12 @@
 <?php
 
-require_once "./src/Element/BookCollection.php";
-require_once "./src/Element/LinkCollection.php";
-require_once "./src/Element/BookContent/BookContented.php";
+namespace SukWs\Bookshelf\Element;
+
+use DOMDocument;
+use DOMNamedNodeMap;
+use DOMNode;
+use SukWs\Bookshelf\Element\BookContent\BookContented;
+use Exception;
 
 class Bookshelf {
 	
@@ -51,6 +55,7 @@ class Bookshelf {
 							break;
 						case "#text":
 							if (empty(trim($rc->nodeValue))) break;
+							throw new Exception("Unsupported element type \"$rc->nodeName\" in root child of Bookshelf");
 						default:
 							throw new Exception("Unsupported element type \"$rc->nodeName\" in root child of Bookshelf");
 					}
@@ -64,7 +69,7 @@ class Bookshelf {
 	/**
 	 * @throws Exception
 	 */
-	public static function parseConfiguration(DOMNode $dom, array &$configurations) {
+	public static function parseConfiguration(DOMNode $dom, array &$configurations): void {
 		for ($rc = $dom->firstChild; $rc != null; $rc = $rc->nextSibling) {
 			if ($rc->nodeName == "#text") {
 				if (!empty(trim($rc->nodeValue)))
@@ -87,7 +92,7 @@ class Bookshelf {
 		}
 	}
 	
-	public static function parseConfigurationAttr (DOMNamedNodeMap $attributes, array &$configurations, array $ignores = array()) {
+	public static function parseConfigurationAttr (DOMNamedNodeMap $attributes, array &$configurations, array $ignores = array()): void {
 		foreach ($attributes as $attr) {
 			if (in_array($attr->name, $ignores)) continue;
 			$configurations[$attr->name] = $attr->value;
diff --git a/src/Element/Link.php b/src/Element/Link.php
index 46aab9d..11588c5 100644
--- a/src/Element/Link.php
+++ b/src/Element/Link.php
@@ -1,6 +1,9 @@
 <?php
 
-require_once "./src/Element/LinkCollection.php";
+namespace SukWs\Bookshelf\Element;
+
+use DOMNode;
+use Exception;
 
 class Link {
 	
@@ -48,7 +51,7 @@ class Link {
 	/**
 	 * @return LinkCollection|null
 	 */
-	public function getParent (): LinkCollection {
+	public function getParent (): ?LinkCollection {
 		return $this->parent;
 	}
 	
diff --git a/src/Element/LinkCollection.php b/src/Element/LinkCollection.php
index 589e47f..a49ce7d 100644
--- a/src/Element/LinkCollection.php
+++ b/src/Element/LinkCollection.php
@@ -1,6 +1,9 @@
 <?php
 
-require_once "./src/Element/Link.php";
+namespace SukWs\Bookshelf\Element;
+
+use DOMNode;
+use Exception;
 
 class LinkCollection {
 	
@@ -38,15 +41,16 @@ class LinkCollection {
 		for ($child = $root->firstChild; $child != null; $child = $child->nextSibling) {
 			switch ($child->nodeName) {
 				case "Link":
-					array_push($node->array, Link::parse($child, $node));
+					$node->array[] = Link::parse($child, $node);
 					break;
 				case "Collection":
-					array_push($node->array, LinkCollection::parse($child, $node));
+					$node->array[] = LinkCollection::parse($child, $node);
 					break;
 				case "#comment":
 					break;
 				case "#text":
 					if (empty(trim($child->nodeValue))) break;
+					throw new Exception("Unsupported element type \"$child->nodeName\" in LinkCollection named \"$name\"");
 				default:
 					throw new Exception("Unsupported element type \"$child->nodeName\" in LinkCollection named \"$name\"");
 			}
@@ -68,7 +72,7 @@ class LinkCollection {
 	/**
 	 * @return LinkCollection|null
 	 */
-	public function getParent (): LinkCollection {
+	public function getParent (): ?LinkCollection {
 		return $this->parent;
 	}
 	
diff --git a/src/Utils/Markdown/CommonMarkExtensions/ExtensionRef.php b/src/Utils/Markdown/CommonMarkExtensions/ExtensionRef.php
index 7ab72f6..fc1100b 100644
--- a/src/Utils/Markdown/CommonMarkExtensions/ExtensionRef.php
+++ b/src/Utils/Markdown/CommonMarkExtensions/ExtensionRef.php
@@ -1,5 +1,7 @@
 <?php
 
+namespace SukWs\Bookshelf\Utils\Markdown\CommonMarkExtensions;
+
 class ExtensionRef {
 	
 }
\ No newline at end of file
diff --git a/src/Utils/Markdown/Parser.php b/src/Utils/Markdown/Parser.php
index 0d53f79..9e9361a 100644
--- a/src/Utils/Markdown/Parser.php
+++ b/src/Utils/Markdown/Parser.php
@@ -1,5 +1,7 @@
 <?php
 
+namespace SukWs\Bookshelf\Utils\Markdown;
+
 use League\CommonMark\ConverterInterface;
 use League\CommonMark\Environment\Environment;
 use League\CommonMark\Extension\Attributes\AttributesExtension;
diff --git a/src/Utils/PageParse.php b/src/Utils/PageParse.php
index 03dbf3f..cdd0030 100644
--- a/src/Utils/PageParse.php
+++ b/src/Utils/PageParse.php
@@ -1,6 +1,6 @@
 <?php
 
-require_once "./src/Utils/StringUtils.php";
+namespace SukWs\Bookshelf\Utils;
 
 class PageParse {
 	
diff --git a/src/Utils/ParsedownExtend.php b/src/Utils/ParsedownExtend.php
index b52629e..b27eec1 100644
--- a/src/Utils/ParsedownExtend.php
+++ b/src/Utils/ParsedownExtend.php
@@ -1,5 +1,7 @@
 <?php
 
+namespace SukWs\Bookshelf\Utils;
+
 use Erusev\Parsedown\Parsedown;
 
 class ParsedownExtend extends Parsedown {
diff --git a/src/Utils/RequestNotExistException.php b/src/Utils/RequestNotExistException.php
index 3f16d0d..f05bcac 100644
--- a/src/Utils/RequestNotExistException.php
+++ b/src/Utils/RequestNotExistException.php
@@ -1,5 +1,9 @@
 <?php
 
+namespace SukWs\Bookshelf\Utils;
+
+use Exception;
+use Throwable;
 
 class RequestNotExistException extends Exception {
 	
diff --git a/src/Utils/StringUtils.php b/src/Utils/StringUtils.php
deleted file mode 100644
index e8845fa..0000000
--- a/src/Utils/StringUtils.php
+++ /dev/null
@@ -1,16 +0,0 @@
-<?php
-
-class StringUtils {
-	
-	/**
-	 * 删除所给字符串的换行符
-	 *
-	 * @param string $str 所给字符串
-	 *
-	 * @return string 剔除换行符的版本
-	 */
-	public static function rmEOL(string $str): string {
-		return str_replace(array("\r\n", "\r", "\n"), "", $str);
-	}
-	
-}
diff --git a/template/footer.php b/template/footer.php
index 0c1827a..6384dd4 100644
--- a/template/footer.php
+++ b/template/footer.php
@@ -1,5 +1,5 @@
-<?php require_once "./src/Data/SiteMeta.php" ?>
-<?php require_once "./src/Data/PageMeta.php" ?>
+<?php use SukWs\Bookshelf\Data\SiteMeta; ?>
+<?php use SukWs\Bookshelf\Data\PageMeta; ?>
 		
 		<!-- Assets(js) --><?php
 		foreach (SiteMeta::getJavascriptList() as $item) {
diff --git a/template/header.php b/template/header.php
index d2d64b6..a207388 100644
--- a/template/header.php
+++ b/template/header.php
@@ -1,5 +1,5 @@
-<?php require_once "./src/Data/SiteMeta.php" ?>
-<?php require_once "./src/Data/PageMeta.php" ?>
+<?php use SukWs\Bookshelf\Data\SiteMeta; ?>
+<?php use SukWs\Bookshelf\Data\PageMeta; ?>
 <!DOCTYPE HTML>
 <html lang="<?= "" // TODO Page language ?>">
 	<head>
diff --git a/template/nav.php b/template/nav.php
index 8770322..94464ce 100644
--- a/template/nav.php
+++ b/template/nav.php
@@ -1,5 +1,5 @@
-<?php require_once "./src/Data/SiteMeta.php" ?>
-<?php require_once "./src/Data/PageMeta.php" ?>
+<?php use SukWs\Bookshelf\Data\SiteMeta; ?>
+<?php use SukWs\Bookshelf\Data\PageMeta; ?>
 <div id="nav-container" class="prevent-animation"><nav id="sidebar">
 		<noscript id="noscript-warn">For now, javascript must be enabled to view this site!!</noscript>
 		<a id="site-title" class="no-style" href="/"><?= SiteMeta::getBookshelf()->getSiteName() ?></a>
diff --git a/template/raw-article.php b/template/raw-article.php
index 7f25ac2..0984edc 100644
--- a/template/raw-article.php
+++ b/template/raw-article.php
@@ -1,7 +1,7 @@
 <?php
 
-require_once "./src/Data/PageMeta.php";
-require_once "./src/Utils/Markdown/Parser.php";
+use SukWs\Bookshelf\Data\PageMeta;
+use SukWs\Bookshelf\Utils\Markdown\Parser;
 
 $pageMarkdownContent = PageMeta::$page->getMarkdownContent();
 
diff --git a/template/raw-book-contents.php b/template/raw-book-contents.php
index 817b043..62d633f 100644
--- a/template/raw-book-contents.php
+++ b/template/raw-book-contents.php
@@ -1,5 +1,5 @@
 <?php
 
-require_once "./src/Data/PageMeta.php";
+use SukWs\Bookshelf\Data\PageMeta;
 
 PageMeta::$page->getSummaryHtml();