自定义MVC

最新推荐文章于 2024-02-21 13:33:49 发布

白画月亮

最新推荐文章于 2024-02-21 13:33:49 发布

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本文链接：https://blog.youkuaiyun.com/qq_40078424/article/details/90905786

本文介绍了MVC设计模式，包括其核心思想和组件职责。Model代表实体域模型，View负责展示，Controller处理用户交互。文章详细阐述了自定义MVC的工作原理，强调主控制器动态调用子控制器来完成业务逻辑，并提供了相关请求路径的获取方法。通过实例展示了如何创建实体类、子控制器和主控制器，以及在JSP界面中实现交互。总结来说，主控制器负责查找并调用合适的子控制器处理用户请求，而子控制器则专注于执行具体的业务操作。

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1. 什么是MVC

1.MVC全名是Model View Controller，是模型(model)－视图(view)－控制器(controller)的缩写，它是一种软件设计典范，用一种业务逻辑、数据、界面显示分离的方法组织代码
Model1 jsp+jdbc
Model2 ->MVC
ps:核心思想：各司其职

2、MVC结构
M: 实体域模型（名词）过程域模型（动词）
V :servlet/action
C: jsp/ios/android

web ：做浏览器请求分发
service: 调用dao处理项目业务的
dao ：操作数据库
注：不能跨层调用，只能出现由上而下的调用
3. 自定义MVC工作原理图主控制动态调用子控制器调用完成具体的业务逻辑（火车、控制台、车轨）请求、主控制器、子控制器
req.getServletPath() 单纯的一个请求
req.getContextPath() 项目名
req.getRequestURI() 项目名+请求
req.getRequestURL() 请求的全路径
以下图为参考：

在这里插入图片描述
实体类的创建(cal)：

public class Cal {
	private String num1;
	private String num2;
	public String getNum1() {
		return num1;
	}
	public void setNum1(String num1) {
		this.num1 = num1;
	}
	public String getNum2() {
		return num2;
	}
	public void setNum2(String num2) {
		this.num2 = num2;
	}

	public Cal() {} 
	
	public Cal(String num1, String num2) {
		this.num1 = num1;
		this.num2 = num2;
	}
	
}

先子控制器：
专门用来处理业务逻辑的

public interface Action {
	 void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException ;
}

再创建主控制器：

public class DispatcherServlet extends HttpServlet{

	private static final long serialVersionUID = -7865425427339716224L;
	
	private Map<String, Action> actionMap = new HashMap<>();

	public void init() {
		actionMap.put("/addCal", new AddCalAction());
		actionMap.put("/delCal", new DelCalAction());
		actionMap.put("/cCal", new cCalAction());
		actionMap.put("/xCal", new xCalAction());
	}
	
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		init();
		String url = req.getRequestURI();
		url = url.substring(url.lastIndexOf("/"), url.lastIndexOf("."));
		Action action = actionMap.get(url);//根据url获取子控制器
		action.execute(req, resp);
	}
}

实现Action类(增加，删除,乘法,除法)：

public class AddCalAction implements Action {
	public void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//增加类
		String num1 = req.getParameter("num1");
		String num2 = req.getParameter("num2");
		req.setAttribute("res", Integer.parseInt(num1)+Integer.parseInt(num2));
		req.getRequestDispatcher("calRes.jsp").forward(req, resp);
	}
}	


public class DelCalAction implements Action {
	public void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//删除类
		String num1 =req.getParameter("num1");
		String num2 =req.getParameter("num1");
		req.setAttribute("res", Integer.valueOf(num1)-Integer.valueOf(num2));
		req.getRequestDispatcher("calRes.jsp").forward(req, resp);
	}
}

public class ChenCalAction implements Action {
	public void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	 	//乘法类
		String num1=req.getParameter("num1");
		String num2=req.getParameter("num2");
		req.setAttribute("res", Integer.valueOf(num1)*Integer.valueOf(num2));
		req.getRequestDispatcher("calRes.jsp").forward(req, resp);
	}
}

public class ChuCalAction implements Action {
	public void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//除法类
		String num1=req.getParameter("num1");
		String num2=req.getParameter("num2");
		req.setAttribute("res", Integer.valueOf(num1)/Integer.valueOf(num2));
		req.getRequestDispatcher("calRes.jsp").forward(req, resp);
	}
}

再在jsp界面实现：

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
	function doSb(val) {
		if(val == 1){
			calForm.action ="${pageContext.request.contextPath }/addCal.action";
		}
		else if(val ==2){
			calForm.action ="${pageContext.request.contextPath }/delCal.action";
		}
		else if(val ==3){
			calForm.action ="${pageContext.request.contextPath }/chenCal.action";
		}
		else if(val ==4){
			calForm.action ="${pageContext.request.contextPath }/chuCal.action";
		}
		calForm.submit();
	}
	
</script>

</head>
<body>
<form id="calForm" name="calForm" action="${pageContext.request.contextPath }/addCal.action">
	num1:<input type="text" name="num1" ><br>
	num2:<input type="text" name="num2" ><br>
	<button onclick="doSb(1)">+</button>
	<button onclick="doSb(2)">-</button>
	<button onclick="doSb(3)">*</button>
	<button onclick="doSb(4)">/</button>
</form>

</body>
</html>

最后结果为：