[开发测试]自定义MVC

思维导图

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?中央控制器

package com.lx.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 org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.beanutils.PropertyUtils;

import com.lx.web.BookAction;
import com.lx.web.GoodsAction;

/**
 * 目标：
 * 	根据自定义mvc框架的原理图	完成	框架的研发
 * @author lx
 * 中央控制器
 * 	寻找子控制器
 *
 */
@WebServlet("*.action")
public class DispatchServlet extends HttpServlet {
		//存放子控制器的容器
		//private Map<String, ActionSupport> actions = new HashMap<String, ActionSupport>();
		private ConfigModel configModel = null;
		//	初始化子控制器容器（集合），经过初始化，actions容器内部就有了子控制器
		//	init,service,destroy
		/*
		 * 需求：
		 * 	在增加一个商品类的增删查改
		 * 步骤：
		 * 	改动init中代码
		 * 思考：
		 * 	能不能不改动代码完成这个需求
		 * 	参考DBAccess的数据源配置文件config.properties
		 * 	1.减少代码改动风险性
		 * 	2.减少代码的编译次数（对于已经部署到服务器后）
		 * 	解决方案：
		 * 	改成子控制器可配置
		 * 	解决步骤：
		 * 	1.必须有配置文件config.xml
		 * 	2.配置文件config.xml中要包含处理业务的子控制器
		 *	3.读取到配置文件config.xml中的对应的处理浏览器请求的子控制器
		 * 	编码
		 * 		...
		 */
	@Override
	public void init() throws ServletException {
		try {
			configModel = ConfigModelFactory.build();
		} catch (Exception e) {
			e.printStackTrace();
		}
		
		//actions.put("/book", new BookAction());
		//actions.put("/goods", new GoodsAction());
		//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.从浏览器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);
		ActionModel actionModel = configModel.pop(uri);
		String type = actionModel.getType();
		ActionSupport action;
		try {
			action = (ActionSupport) Class.forName(type).newInstance();
				//ActionSupport action = new BookAction()
			if(action instanceof ModelDriver) {
				ModelDriver m = (ModelDriver) action;
				Object obj = m.getModel();
			//有对象
			//接受所有的前端JSP传递到后台的参数
				Map<String, String[]> parameterMap = req.getParameterMap();
			//对 对象 赋值
			//PropertyUtils.getProperty(obj, "")
				BeanUtils.populate(obj, parameterMap);
			}
			//execute->delete
			String res = action.execute(req, resp);
			/*
			 * 思路
			 * 1.方法执行完毕必须有一个返回值
			 * 2.通过返回值决定是否重定向，还是转发
			 * 3.通过返回值决定跳转哪一个页面
			 */
			ForwardModel forwardModel = actionModel.pop(res);
			if(forwardModel.isRedirect()) {
				resp.sendRedirect(req.getContextPath()+forwardModel.getPath());
			}else {
				req.getRequestDispatcher(forwardModel.getPath()).forward(req, resp);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

?子控制器

package com.lx.web;

import java.io.IOException;
import java.lang.reflect.Field;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.lx.entity.Book;
import com.lx.framework.ActionSupport;
import com.lx.framework.ModelDriver;

public class BookAction extends ActionSupport implements ModelDriver<Book>{
	private Book book = new Book();
	
	private String delete(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("BookAction调用bookDao.delete()...");
		/*
		 * 需求：删除数据后跳转到书籍展示页面
		 * 缺陷：1.出现大量重复代码	2.不好管理（增删改重新跳转到查询界面）
		 * 解决方案：在一个地方统一管理重定向还是转发，并且是定位跳转到哪一个页面
		 * 预测结果
		 * 	BookAction调用bookDao.delete()...
		 * 	BookAction调用bookDao.list()...
		 * 
		 */
			//try {
			//req.getRequestDispatcher("/bookList.jsp").forward(req, resp);
			//resp.sendRedirect("/bookList.jsp");
			//this.list(req, resp);
			//} catch (Exception e) {
			//e.printStackTrace();
			//		}
			return "toList";
		}
	
	private void add(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("BookAction调用bookDao.add()...");
	}
	
	private String list(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("BookAction调用bookDao.list()...");
//		try {
//			req.getRequestDispatcher("/bookList.jsp").forward(req, resp);
//		} catch (Exception e) {
//			e.printStackTrace();
//		}
		return "list";
	}
	
	private void ref(HttpServletRequest req, HttpServletResponse resp) {
			//解决参数实体类封装的问题
			/*
			 * 缺陷：对于前端传参，实体类属性值封装req.getParammeter("")代码 是重复的
			 * 需求：做一个book的新增功能
			 * 思考：将JSP参数塞进实体类的属性中，问题是每个实体类的属性是不一样的，没办法做到代码的完全重复
			 * 思路：
			 * 	不知道是哪一个实体类->泛型T
			 * 	不知道这个实体类有哪些属性，但是又要给这些属性赋值->反射动态设置属性值
			 * 解决：泛型+反射
			 * 编码：
			 * 	模型驱动接口：ModelDriver
			 */
//		Book book = new Book();
//		book.setBid(req.getParameter("bid"));
//		book.setBname(req.getParameter("bname"));
//		book.setPrice(req.getParameter("price"));
//		book.setAuthor(req.getParameter("author"));
//		book.setPublish(req.getParameter("publish"));
		System.out.println(book);
		System.out.println("BookAction调用bookDao.ref(book)...");
	}

	@Override
	public Book getModel() {
		return book;
	}
}

?配置文件

<?xml version="1.0" encoding="UTF-8"?>
<config>
	<action path="/book" type="com.lx.web.BookAction">
		<forward name="list" path="/bookList.jsp" redirect="false" />
<!-- 		增删改操作之后要再一次查询数据库的新的数据做展示 -->
		<forward name="toList" path="/book.action?methodName=list" redirect="true" />
	</action>
</config>

?页面展示

<%@ 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> 
<hr>
演示原有的初始化子控制器的缺陷
<a href="${pageContext.request.contextPath }/goods.action?methodName=add">增加</a>
<a href="${pageContext.request.contextPath }/goods.action?methodName=delete">删除</a>
<a href="${pageContext.request.contextPath }/goods.action?methodName=edit">修改</a>
<a href="${pageContext.request.contextPath }/goods.action?methodName=list">查询</a>
<hr>
解决参数实体类封装的问题
<form action="${pageContext.request.contextPath }/book.action?methodName=ref" method="post">
	<input type="text" name="bid" value="22">
	<input type="text" name="bname" value="yj">
	<input type="text" name="price" value="228">
	<input type="text" name="author" value="zy">
	<input type="text" name="publish" value="zking">
	<input type="text" name="remark" value="beizhu">
	<input type="submit">
	<hr>
</form>
</body>
</html>