【郑州校区】JavaWeb18-HTML篇笔记（一）

本帖最后由谷粒姐姐于 2018-6-6 11:22 编辑

1.1 上次课内容回顾:

注解:

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   * JDK中的三个注解:[/align]    * 自定义注解:
        * @interface
        * 注解类型:基本类型,String,Class,注解,枚举,以上类型的一维数组.
    * 注解的反射:
Servlet3.0
    * 注解开发:
    * 文件上传:
    * 异步请求:
动态代理：
    * Proxy.newProxyInstance(ClassLoader cl,Class[] interfaces,InvocationHandler handler);
    * 如何增强类中的某个方法:
类加载器:
    * 引导类加载器:
    * 扩展类加载器:
    * 应用类加载器:

1.2 网上商城的实战的案例:1.2.1 需求：

1.2.2 数据库设计:

1.2.3 网上商城用户模块的代码实现:(前台)1.2.3.1 编写一个通用的Servlet:

传统方式的开发一个请求对应一个Servlet:这样的话会导致一个模块的Servlet过多,导致整个项目的Servlet都会很多.能不能做一个处理?让一个模块致用一个Servlet处理请求.

注册:http://localhost:8080/store_2.0/UserServlet?method=regist

登录:http://localhost:8080/store_2.0/UserServlet?method=login

激活:http://localhost:8080/store_2.0/UserServlet?method=active

商品查询所有：http://localhost:8080/store_2.0/ProductServlet?method=findAll

商品查询某个：http://localhost:8080/store_2.0/ProductServlet?method=findById

传统:

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public class UserServlet extends HttpServlet{
    public void service(HttpServletRequest req,HttpServletResponse resp){
        // 接收参数:
        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){
        // 接收参数:
        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”);
          // 获得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){
     
   }
}