servlet的优化即封装

servlet的封装

比如：用户操作相关servlet管理 

Baseservlet

package cn.hoagn.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;


public class BaseServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //  super.service(req, resp);

        System.out.println("方法被执行了");

        // 获取路径
        String requestURI = req.getRequestURI();
        StringBuffer requestURL = req.getRequestURL();
        System.out.println("requestURI:"+requestURI+"  requestURL:"+requestURL); // requestURI:/user/da  requestURL:http://localhost/user/da
        // 截取
        String methonName = requestURI.substring(requestURI.lastIndexOf("/")+1); //
        System.out.println(methonName); // da

        System.out.println(this);  // cn.itcast.travel.servlet.UserServlet@3599a2d1

        // 分发

        try {
            // 获取方法
            Method declaredMethod = this.getClass().getMethod(methonName, HttpServletRequest.class, HttpServletResponse.class);
            // 忽略访问权限修饰，获取方法
//            Method declaredMethod = this.getClass().getDeclaredMethod(methonName, HttpServletRequest.class, HttpServletResponse.class);
            //暴力反射
//            declaredMethod.setAccessible(true);

            // 执行方法
            declaredMethod.invoke(this,req,resp);

        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }


    }
}

UserServlet

package cn.hogan.servlet;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/user/*")
public class UserServlet extends BaseServlet {
    public void add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("执行了add方法");
    }

    public void get(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("执行了get方法");
    }
}