public class BookServlet extends HttpServlet {
	
	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}
    //建立BookService物件
	private BookService bookService = new BookService();
	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		/*利用java反射機制實現自動呼叫類的方法 :
		 * 聲明後利用反射，當JSP等介面給出連結 bookServlet?method=''時呼叫bookServlet相應的方法
		        比如：books.JSP介面的 <a href="bookServlet?method=getBooks">呼叫相應的getBooks（）方法*/	
		
		//1.request呼叫宣告methodName獲取方法名
		String methodName = request.getParameter("method");
		try {
			 //2.獲取該類所需求的方法（非公共許可權）
			Method method = getClass().getDeclaredMethod(methodName, HttpServletRequest.class, HttpServletResponse.class);
			//3.設定非公共許可權方法可呼叫
			method.setAccessible(true);
			//4.invoke呼叫反射方法的實現
			method.invoke(this, request, response);
		} catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException(e);
		}
	}
	//獲取圖書資訊
		protected void getBooks(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
			String pageNoStr = request.getParameter("pageNo");
			String minPriceStr = request.getParameter("minPrice");
			String maxPriceStr = request.getParameter("maxPrice");
			
			int pageNo = 1;
			int minPrice= 0;
			int maxPrice = Integer.MAX_VALUE;
			//request.getParameter返回值是String，需要進行強制型別轉換為int型別
			try {
				pageNo = Integer.parseInt(pageNoStr);
			} catch (NumberFormatException e) {}
			
			try {
				minPrice = Integer.parseInt(minPriceStr);
			} catch (NumberFormatException e) {}
			
			try {
				maxPrice = Integer.parseInt(maxPriceStr);
			} catch (NumberFormatException e) {}
			//初始化構造器傳參建立封裝條件的CriteriaBook物件
			CriteriaBook criteriaBook = new CriteriaBook(minPrice, maxPrice, pageNo);
			//傳參CriteriaBook物件    ，呼叫上面建立的bookService物件獲取page物件的方法例項化page物件
			Page<Book> page = bookService.getPage(criteriaBook);
			//設定page物件進行賦值
			request.setAttribute("bookpage", page);
			//轉發資料到books介面
			request.getRequestDispatcher("/WEB-INF/pages/books.jsp").forward(request, response);
		}
}