自定义mvc框架（中）

客官°小女子只卖身不卖艺 2024-03-17 13:46 17阅读 0赞

![d9291045e7ea4b14b46c0a628d9b8625.jpeg][]

## 一.前节回顾 ##

> **在前一节中，我们了解了：**
> 
> **1.什么是mvc框架？**
> 
> **2.mvc框架在企业中的大量使用**
> 
> **3.mvc框架和 三层架构区别？**
> 
> **4.分析mvc框架代码和缺陷**
> 
> **5.利用自定义mvc框架去优化三层架构 ！**
> 
> **所以你学废了吗？**

## 二.继续优化mvc框架 ##

### 1..将中央控制器中的Action容器，变成可控制! ###

> 缺点**：中央控制器 加载不可以灵活配置**

#### 1.1老版方法 ####

> 首先我们的第一个问题就是**子控制器的初始化配置问题**，我在上篇中的最后一个版本“反射增强版”演示到如果需要对项目中的其他表进行操作，就必须编**写子控制器并进行配置**。通过这样操作就可以将action中的容器便活，可以适应各种使用
> 
> ![5257209c4fb740c48b5c4e90df2562ad.png][]

#### 1.2新版方法 ####

> 在**新版本**我们通过**XML建模的方法**来实现将原来写死的，将其变活！
> 
> ![5e2a955ddcd945c78cc347fad2d85b5b.png][]
> 
> 然后那个build方法（通过此方法来调用我们的xml文件）展示为
> 
> ![8fe19fd3558c4e4b80ec32528e773786.png][]
> 
> xml文件 ![23df5665b9ed4c92a6ac6c0a0337b10d.png][]
> 
> 在typr位置进行修改**，路径**是**你实现servelt的方法**

#### 1.3相对应的一些文件 ####

##### 1.3.1中央控制器 #####

package com.lz.fraamework;
    
    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 org.apache.commons.beanutils.BeanUtils;
    
    import com.lz.fraamework.model.ActionModel;
    import com.lz.fraamework.model.ConfigModel;
    import com.lz.fraamework.model.ConfigModelFactory;
    import com.lz.fraamework.model.ForwardModel;
    import com.lz.servelt.OederAction;
    import com.lz.servelt.bookAction;
    
    /**
     * 对应图中的 ActionServelt:中央控制器 调用反射代码块
     * 
     * @author lzzxq
     *
     */
    @WebServlet("*.action")
    public class DispathServelt extends HttpServlet {
    	private static final long serialVersionUID = 1L;
    	private ConfigModel configModel;
    	@Override
    	// 服务器启动就启用
    	public void init() throws ServletException {
    		try {
    			configModel = ConfigModelFactory.build();
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    
    	protected void doGet(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
    		doPost(request, response);
    	}
    
    	protected void doPost(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
    		@SuppressWarnings("unused")
    		// jsp传递的参数
    		String methodName = request.getParameter("methodName");
    		// 获取浏览器路径的book
    		String uri = request.getRequestURI();
    		uri = uri.substring(uri.lastIndexOf("/"), uri.lastIndexOf("."));
    		// Action action = actionMap.get(uri);
    
    		// 通过 uri= 在configModel寻找
    		ActionModel actionmodel = configModel.pop(uri);
    		if (actionmodel == null) {
    			throw new RuntimeException("action not config");
    		}
    		String type = actionmodel.getType();
    		// bookAction bk=new bookAction();
    		Action action;
    		try {
    			action = (Action) Class.forName(type).newInstance();
    			if(action instanceof ModelDriver) {
    				ModelDriver md = (ModelDriver) action;
    				Object bean = md.getModel();
    				BeanUtils.populate(bean, request.getParameterMap());
    			}
    			// 具体业务代码返回值 增加，删除，修改，查看 tolist list
    			String res = action.ececute(request, response);
    			// 通过此方法 获取返回值
    			ForwardModel forwardModel = actionmodel.pop(res);
    			if (forwardModel != null) {
    				boolean redirect = forwardModel.isRedirect();
    				String path = forwardModel.getPath();
    				if (redirect) {
    					response.sendRedirect(request.getContextPath() + "/" + path);
    				} else {
    					request.getRequestDispatcher(path).forward(request, response);
    				}
    			}
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    
    	}
    
    }

##### 1.3.2需要配置的xml文件 #####

<?xml version="1.0" encoding="UTF-8"?>
 
 <config>
 	<action path="/order" type="com.lz.servelt.OederAction">
 		<forward name="failed" path="/reg.jsp" redirect="false" />
 		<forward name="success" path="/login.jsp" redirect="true" />
 	</action>
 
 	<action path="/book" type="com.lz.servelt.bookAction">
 		<forward name="list" path="/res.jsp" redirect="false" />
 		<forward name="toList" path="/res.jsp" redirect="true" />
 	</action>
 </config>

##### 1.3.3实现servelt的方法 #####

package com.lz.servelt;
    
    import java.io.IOException;
    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.lz.fraamework.Action;
    
    public class OederAction extends  Action{
    	/**
    	 * 在此实现Orderservelt的方法
    	 * @param request
    	 * @param response
    	 */
    	private void Ck(HttpServletRequest request, HttpServletResponse response) {
    		System.out.println("ck....订单方法....刘兵小狗狗");
    		
    	}
    
    	private void upd(HttpServletRequest request, HttpServletResponse response) {
    		System.out.println("upd....订单方法");
    		
    	}
    
    	private void del(HttpServletRequest request, HttpServletResponse response) {
    		System.out.println("del....订单方法");
    		
    	}
    
    	private void add(HttpServletRequest request, HttpServletResponse response) {
    		System.out.println("add....订单方法");
    		
    	}
    
    
    }

package com.lz.servelt;
 
 import java.io.IOException;
 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.lz.entity.Book;
 import com.lz.fraamework.Action;
 import com.lz.fraamework.ModelDriver;
 
 public class bookAction extends Action implements ModelDriver<Book>{
 	private Book book = new Book();
 	/**
 	 * 在此实现servelt的方法
 	 * @param request
 	 * @param response
 	 * @throws Exception 
 	 * @throws ServletException 
 	 */
 	private String add(HttpServletRequest request, HttpServletResponse response) throws Exception {
 		Map<String, String[]> parameterMap = request.getParameterMap();
 		/* 1.要有表对应的类属性对象 Book book
 		 * 2.获取到所有的参数 及参数 
 		 * 3.将参数值封装到表对应的对象中
 		 * 4.要做到所有子控制器通用
 		 */
 //		String bid = request.getParameter("bid");
 //		String bname = request.getParameter("bname");
 //		String price = request.getParameter("price");
 //		Book book = new Book();
 //		book.setBid(Integer.valueOf(bid));
 //		book.setBname(bname);
 //		book.setPrice(Float.valueOf(price));
 		System.out.println("add....方法");
 		//request.getRequestDispatcher("res.jsp").forward(request, response);
 		request.setAttribute("content", "送快递盒饭");
 		return "toList";
 		
 	}
 	
 	
 	private String Ck(HttpServletRequest request, HttpServletResponse response) throws ServletException, Exception {
 		System.out.println("ck....方法....刘兵小狗狗");
 	//	response.sendRedirect("res.jsp");
 		request.setAttribute("content", "送快递盒饭");
 		return "List";
 		
 		
 	}
 
 	private String upd(HttpServletRequest request, HttpServletResponse response) throws Exception {
 		System.out.println("upd....方法");
 //		request.getRequestDispatcher("res.jsp").forward(request, response);
 		request.setAttribute("content", "送快递盒饭");
 		return "toList";
 		
 	}
 
 	private String del(HttpServletRequest request, HttpServletResponse response) throws Exception {
 		System.out.println("del....方法");
 	//	request.getRequestDispatcher("res.jsp").forward(request, response);	
 		request.setAttribute("content", "送快递盒饭");
 		return "toList";
 	}
 
 
 	@Override
 	public Book getModel() {
 		// TODO Auto-generated method stub
 		return book;
 	}
 
 
 
 
 }

--------------------

### 2.针对于反射调用业务代码，最终页面跳转 ###

#### 1.老版的页面跳转 ####

> request.getRequestDispatcher("res.jsp").forward(request, response);
> 
> response.sendRedirect("res.jsp");
> 
> 无非是通过这两个方法进行封面跳转，**但是使用这种页面跳转在每一个页面都要写东，属于重复代码**

#### 2.新版本 ####

> ![b1a65e48d89d4bf499b5c9aeefaef1e3.png][]
> 
> 实现思路：定义一个res,用此来接受我们的m.invoke方法并且将我们的方法从void变成String
> 
> 在一个return 返回res
> 
> 其次：
> 
> ![9fa16e76bf4248b8aa485581a92a3e06.png][]
> 
> 将我们的servelt方法void变成String 在一个return 返回“List”or"toList" （查询）为后面的配置xml做准备
> 
> ![31ab6b510fd04a8581530eecf9bca12e.png][]
> 
> 将name属性变成 list or ltoist 然后把path路径变成我们要跳转的页面！

> 接着进行一个if判断是转发，还是重定向？
> 
> ![7519c9d35c4240fdae3b87c4e991766d.png][]

--------------------

### 3.jsp页面参数传递后台的代码优化字段太多有影响！ ###

#### 3.1老版本的封装实体，获取参数 ####

> ![f75eb3dd796d41e59a10a30558293581.png][]
> 
> 弊端：使用于字段名比较少，如果字段名太多就会增加代码数量，并且在编码的时候很容易出现错误 ，耗费时间

#### 3.2新版本 ####

> 模型驱动接口 替换 Book book = new Book();
> 
> ![383e19cec8074a588e532f67d4e8e3c6.png][]
> 
> 定义一个集合保存存储的数据
> 
> Map<String, String\[\]> parameterMap = request.getParameterMap();
> 
> 在 DispathServelt判断是否实现接口
> 
> ![a4551c61efc941d78fc88e1286f5595b.png][]

## 三.对于这些方法总结 ##

> 版本5
> 
> 常识：查询必然转发，增删改使用重定向
> 
> 弊端：中央控制器中的action容器加载不可以灵活配置
> 
> <hr>
> 
> <a href="book.action?methodName=add">增加</a>
> 
> <a href="book.action?methodName=del">删除</a>
> 
> <a href="book.action?methodName=upd">修改</a>
> 
> <a href="book.action?methodName=list">查询</a>
> 
> 版本6
> 
> 弊端：jsp传递到后台，封装到实体类的代码过多
> 
> <hr>
> 
> <a href="book.action?methodName=add&bid=1&bname=nb&price=9.9">增加</a>
> 
> <a href="book.action?methodName=del">删除</a>
> 
> <a href="book.action?methodName=upd">修改</a>
> 
> <a href="book.action?methodName=list">查询</a>
> 
> 版本7
> 
> <hr>
> 
> <a href="book.action?methodName=add&bid=1&bname=nb&price=9.9">增加</a>
> 
> <a href="book.action?methodName=del">删除</a>
> 
> <a href="book.action?methodName=upd">修改</a>
> 
> <a href="book.action?methodName=list">查询</a>
> 
> </body>
> 
> </html>

**所以你学废了吗？**

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