BaseServlet抽取

　　优化Servelet，减少Servlet数量，现在是一个功能一个Servlet，将其优化为一个模块一个Servlet相当于在数据库中一张表对应一个Servlet，现在Servlet中提供不同的方法，完成用户的请求，

　　　　图解：

public class BaseServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        System.out.println("BaseServlet的service的方法被执行了...");
//        完成方法分发
//        获取请求路径
        String uri = req.getRequestURI();
        System.out.println("请求的路径"+uri);
//        获取方法名称
        String name = uri.substring(uri.lastIndexOf("/") + 1);
        System.out.println("方法名称"+name);
//        获取方法对象Method
        System.out.println(this);
        try {
//        忽略访问权限符
            Method method = this.getClass().getDeclaredMethod(name, HttpServletRequest.class, HttpServletResponse.class);
//        暴力反射
//            method.setAccessible(true);
//        执行方法
            method.invoke(this,req,resp);
        } catch (NoSuchMethodException e) {
            throw new RuntimeException(e);
        } catch (InvocationTargetException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        }

    }

}

@WebServlet("/user/*")
public class UserServlet extends BaseServlet{
    public void add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("user的add方法...");
    }
    public void find(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("user的find方法...");
    }
}