?代码展示
package com.zking.framework;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.zking.web.BookAction;
/**
* 目标：
* 根据自定义mvc框架的原理图完成 框架的研发
* @author zjjt
*中央控制器
*寻找子控制器
*/
@WebServlet("*.action")
public class DispatchServlet extends HttpServlet{
//放子控制器的容器
private Map<String, ActionSupport> actions=new HashMap<String, ActionSupport>();
//初始化子控制器容器（集合）,经过初始化，actions容器内存就有了子控制器
//init,service,destroy
@Override
public void init() throws ServletException {
actions.put("/book", new BookAction());
/*actions.put("/order", new BookAction());
actions.put("/OrderItem", new BookAction());*/
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//完成寻找子控制的过程
//浏览器：http://localhost:8080/t266_mvc/book.action?methodName=add
//目标：BookAction.add()..
/**
* 思路：
* 1.从游览器URL中获取到“/book”字符串
* 2.在子控制器容器中拿到BookAction
* 3.BookAction.add()
*/
String uri = req.getRequestURI();
uri = uri.substring(uri.lastIndexOf("/"),uri.lastIndexOf("."));
//action=BookAction
ActionSupport action = actions.get(uri);
//ActionSupport action=new BookAction()
action.execute(req, resp);
}
}
package com.zking.web;
import java.io.IOException;
import java.lang.reflect.Method;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* 目标：自定义mvc的工作原理
* 1.什么是自定义mvc框架
* 自定义mvc 框架
* 2.它的运行原理
* 2.1代码演绎过程
* 2.2总结代码运行原理
* 思考：
* 什么是mvc
* Model模型，View视图，controller控制层
* mvc的出现原因：各司其职
* 一个餐馆：点餐，收银，炒菜，上菜，收盘子，洗盘子
* 发展壮大：点菜员，收银员，厨师，传菜员，洗碗阿姨
*
* 不足：
* Model模型：
* Dao层：（增删改 查）
* 1.建立数据库连接
* 2.预定义对象Preparestatement
* 3.执行查询
* 4.处理结果集
*
* 通用分页解决了上面问题
* View视图：
* 1.重复的HTML分页条代码
* 2.重复的JS代码
* 自定义page标签
* controller控制层：
* 1.重写了doGet,doPost,并且doGet没有用
* 2.参数的封装代码long余
* req.getParammeter("xxx");
* 3.对于跳转页面的代码是重复的
* 重定向和转发
* 解决方法：
* 自定义mvc就出现了
* 框架：反射+设计模式 案列：通用分页+自定义page标签+自定义mvc的组合
* @author zjjt
*
*/
/*@WebServlet("/book.action")*/
public class BookServlet extends HttpServlet{
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
/**
* 增删改查缺陷
* 当需求发生改变，或者新增需求的时候，需要改动下面代码 load
*
* 解决方案
* 前台传剃methodName到后台，实际就是想要调用当前类对象的methodName方法
*
*/
String methodName = req.getParameter("methodName");
try {
Method m = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
m.setAccessible(true);//访问权限
m.invoke(this, req,resp);
} catch (Exception e) {
e.printStackTrace();
}
/*if("add".equals(methodName)) {
add(req,resp);
}
else if("delete".equals(methodName)) {
delete(req,resp);
}
else if("edit".equals(methodName)) {
edit(req,resp);
}
else if("list".equals(methodName)) {
list(req,resp);
}*/
}
private void add(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("bookDao.add()...");
}
private void delete(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("bookDao.delete()...");
}
private void edit(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("bookDao.edit()...");
}
private void list(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("bookDao.list()...");
}
private void load(HttpServletRequest req, HttpServletResponse resp) {
//修改页面数据回显
System.out.println("bookDao.load()...");
}
private void ref(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("bookDao.ref()...");
}
}
package com.zking.framework;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* 1.运行/处理前台的浏览器请求
* 2.运行JSP传剃刀后台的方法字符串所代表的方法
* @author zjjt
*
*/
public interface Action {
public void execute(HttpServletRequest req, HttpServletResponse resp);
/*private void delete(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("bookDao.delete()...");
}
private void edit(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("bookDao.edit()...");
}
private void list(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("bookDao.list()...");
}
private void load(HttpServletRequest req, HttpServletResponse resp) {
//修改页面数据回显
System.out.println("bookDao.load()...");
}
private void ref(HttpServletRequest req, HttpServletResponse resp) {
//修改页面数据回显
System.out.println("bookDao.ref()...");
}*/
}
package com.zking.framework;
import java.lang.reflect.Method;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ActionSupport implements Action{
@Override
public void execute(HttpServletRequest req, HttpServletResponse resp) {
String methodName = req.getParameter("methodName");
try {
Method m = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
m.setAccessible(true);//访问权限
m.invoke(this, req,resp);
} catch (Exception e) {
e.printStackTrace();
}
}
}
package com.zking.web;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.zking.framework.ActionSupport;
public class BookAction extends ActionSupport{
//execute
private void delete(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("BookAction调用bookDao.delete()...");
}
private void list(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("BookAction调用bookDao.list()...");
}
private void ref(HttpServletRequest req, HttpServletResponse resp) {
System.out.println("BookAction调用bookDao.ref()...");
req.getRequestDispatcher("index.jsp");
}
}
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
目前多数人增删改查的代码
<a href="${pageContext.request.contextPath }/book/add">增加</a>
<a href="${pageContext.request.contextPath }/book/delete">删除</a>
<a href="${pageContext.request.contextPath }/book/edit">修改</a>
<a href="${pageContext.request.contextPath }/book/list">查询</a>
<hr>
增删改查的代码V2.0
<a href="${pageContext.request.contextPath }/book.action?methodName=add">增加</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=delete">删除</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=edit">修改</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=list">查询</a>
<hr>
增删改查的代码V3.0
<a href="${pageContext.request.contextPath }/book.action?methodName=load">回显</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=ref">关联</a>
</body>
</html>运行代码结果展示
?目标：自定义mvc的工作原理
?* 1.什么是自定义mvc框架
?* ?? ??? ?自定义mvc?? ??? ?框架
?* 2.它的运行原理
?* ?? ??? ?2.1代码演绎过程
?* ?? ??? ?2.2总结代码运行原理
?* 思考：
?* ?? ??? ?什么是mvc
?* Model模型，View视图，controller控制层
?* mvc的出现原因：各司其职
?* 一个餐馆：点餐，收银，炒菜，上菜，收盘子，洗盘子
?* 发展壮大：点菜员，收银员，厨师，传菜员，洗碗阿姨
?*?
?* 不足：
?* Model模型：
?* ?? ??? ?Dao层：（增删改 ?查）
?* ?? ??? ??? ?1.建立数据库连接
?* ?? ??? ??? ?2.预定义对象Preparestatement
?* ?? ??? ??? ?3.执行查询
?* ?? ??? ??? ?4.处理结果集
?* ?? ??? ?
?* ?? ??? ?通用分页解决了上面问题
?* View视图：
?* ?? ??? ??? ?1.重复的HTML分页条代码
?* ?? ??? ??? ?2.重复的JS代码
?* ?? ??? ??? ?自定义page标签
?* controller控制层：
?* ?? ??? ??? ?1.重写了doGet,doPost,并且doGet没有用
?* ?? ??? ??? ?2.参数的封装代码long余
?* ?? ??? ??? ?req.getParammeter("xxx");
?* ?? ??? ??? ?3.对于跳转页面的代码是重复的
?* ?? ??? ??? ??? ?重定向和转发
?* 解决方法：
?* ?? ??? ?自定义mvc就出现了
?* ?? ??? ?框架：反射+设计模式 ? ?案列：通用分页+自定义page标签+自定义mvc的组合
?? ??? ? 增删改查缺陷
?? ??? ? 当需求发生改变，或者新增需求的时候，需要改动下面代码??
?? ??? ? ?
?? ??? ? ?解决方案
?? ??? ? ? ?前台传剃methodName到后台，实际就是想要调用当前类对象的methodName方法
? ? ? ? ?
? ? ? ? ?