* JDK中的三個註解:[/align]    * 自定義註解:
        * @interface
        * 註解類型:基本類型,String,Class,註解,枚舉,以上類型的一維數組.
    * 註解的反射:
Servlet3.0
    * 註解開發:
    * 文件上傳:
    * 異步請求:
動態代理：
    * Proxy.newProxyInstance(ClassLoader cl,Class[] interfaces,InvocationHandler handler);
    * 如何增強類中的某個方法:
類加載器:
    * 引導類加載器:
    * 擴展類加載器:
    * 應用類加載器:
 

1.2 網上商城的實戰的案例:1.2.1 需求：
1.2.2 數據庫設計:

1.2.3 網上商城用戶模塊的代碼實現:(前臺)1.2.3.1 編寫一個通用的Servlet:
傳統方式的開發一個請求對應一個Servlet:這樣的話會導致一個模塊的Servlet過多,導致整個項目的Servlet都會很多.能不能做一個處理?讓一個模塊致用一個Servlet處理請求.
註冊:http://localhost:8080/store_2.0/UserServlet?method=regist
登錄:http://localhost:8080/store_2.0/UserServlet?method=login
激活:http://localhost:8080/store_2.0/UserServlet?method=active

public class UserServlet extends HttpServlet{
    public void service(HttpServletRequest req,HttpServletResponse resp){
        // 接收參數:
        String methodName = request.getParameter(“method”);
        if(“regist”.equals(methodName)){
            regist(req,resp);
        }else if(“login”.equals(methodName)){
            login(req,resp);
       }
   }
   public void regist(HttpServletRequest req,HttpServletResponse resp){
   }
   public void login(HttpServletRequest req,HttpServletResponse resp){
   }
}
public class ProductServlet extends HttpServlet{
    public void service(HttpServletRequest req,HttpServletResponse resp){
        // 接收參數:
        String methodName = request.getParameter(“method”);
        if(“findAll”.equals(methodName)){
            findAll(req,resp);
        }else if(“findById”.equals(methodName)){
            findById(req,resp);
       }
   }
   public void findAll(HttpServletRequest req,HttpServletResponse resp){
   }
   public void findById(HttpServletRequest req,HttpServletResponse resp){
   }
}
 

反射:

public class BaseServlet extends HttpServlet{
     public void service(HttpServletRequest req,HttpServletResponse resp){
          // http://localhost:8080/store_2.0/UserServlet?method=regist
          // http://localhost:8080/store_2.0/ProductServlet?method=findAll
          String methodName = request.getParameter(“method”);
          // 獲得Class:
          Class clazz = this.getClass();
          Method method = clazz.getMethod(methodName,HttpServletRequest.class,HttpSerlvetResponse.class);
          String path = (String)method.invoke(this,req,resp);
          if(path != null){
              req.getRequestDispatcher(path).forward(req,resp);
          }
     }
}
public class UserServlet extends BaseServlet {
   public String regist(HttpServletRequest req,HttpServletResponse resp){

         return “/login.jsp”;
   }
   public String login(HttpServletRequest req,HttpServletResponse resp){
         return “/index.jsp”;
   }
}
public class ProductServlet extends BaseServlet{
   public String findAll(HttpServletRequest req,HttpServletResponse resp){

   }
   public String findById(HttpServletRequest req,HttpServletResponse resp){

   }
}

JavaWeb18-HTML篇筆記（一）