Custom MVC framework [A]

MVC framework of thought

1. What is MVC?
MVC full name is the Model View Controller, is a model (model) - view (view) - abbreviation controller (controller), and
it is a software design model, in a business logic, data, interface show a method of separating an organization code.

MVC core idea : their duties, that is, each doing.

2, MVC structure

M: Entity domain model (noun), the process domain model (verb)
V: JSP / iOS / Android
C: the servlet / Action

do distribute web browser requests a
service call processing dao project operations
dao database operations

Note 1: You can not cross-layer calls
Note 2: You can only call top-down appearance

In the MVC framework to understand the premise of thinking first to know about its working schematics [core]

central control dynamic invocation sub-controller calls to accomplish specific business logic

Summary:
The central controller: if there's a sub-controller to handle user requests, to process requests if you call the sub-controller; not on the error, it can not process the request.
The sub-controller: is treated with a user request.

case study

Using a main controller and sub-controller of the basic functions of a computer
entity class 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(String num1, String num2) {
		super();
		this.num1 = num1;
		this.num2 = num2;
	}
	public Cal() {
		super();
	}
}

main controller

/**
 * 主控制器
 * @author zhouyanpeng
 *
 */
public class DispatcherServlet extends HttpServlet {

	private static final long serialVersionUID = -7094025920085803724L;
	private Map<String, Action> actionMap=new HashMap<>();
	
	//初始化方法
	public void init() {
		//添加子控制器
		actionMap.put("/addCal", new AddCalAction());
		actionMap.put("/delCal", new DelCalAction());
		actionMap.put("/chenCal", new ChenCalAction());
		actionMap.put("/chuCal", new ChuCalAction());
	}	
	@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 {
		init();//初始化
		String url = req.getRequestURI();//MVC/xxx.action
		url = url.substring(url.lastIndexOf("/"), url.lastIndexOf("."));
//		相当于向上转型
		Action action = actionMap.get(url);//根据url获取子控制器  
		action.execute(req, resp);
	}
}

Sub-controller interface

/**
 * 子控制器
 *    专门用来处理业务逻辑
 * @author zhouyanpeng
 *
 */
public interface Action {
	void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException ;
}

Write Math class

addition

public class AddCalAction implements Action {
	@Override
	public void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		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);
	}
}

Subtraction

public class DelCalAction implements Action {
	@Override
	public void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		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);
	}
}

multiplication

public class ChenCalAction implements Action {
	@Override
	public void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		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);
	}
}

division

public class ChuCalAction implements Action {
	@Override
	public void execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		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);
	}
}

Configure the web

 <servlet>
 	<servlet-name>dispatcherServlet</servlet-name>
 	<servlet-class>com.zyp.framework.DispatcherServlet</servlet-class>
 </servlet>
 
 <servlet-mapping>
 	<servlet-name>dispatcherServlet</servlet-name>
 	<url-pattern>*.action</url-pattern>
 </servlet-mapping>

test

<script type="text/javascript">
	function doSub(value){
		if(value==1){
			calForm.action="${pageContext.request.contextPath}/addCal.action";
		}
		else if(value==2){
			calForm.action="${pageContext.request.contextPath}/delCal.action";
		}
		else if(value==3){
			calForm.action="${pageContext.request.contextPath}/chenCal.action";
		}
		else{
			calForm.action="${pageContext.request.contextPath}/chuCal.action";
		}
		calForm.submit();
	}
	
</script>

</head>
<body>
	<form id="claForm" name="calForm" action="">
		num1:<input type="text" name="num1" /><br/>
		num2:<input type="text" name="num2" /><br/>
		<input type="button" onclick="doSub(1)" value="+" />
		<input type="button" onclick="doSub(2)" value="-" />
		<input type="button" onclick="doSub(3)" value="x" />
		<input type="button" onclick="doSub(4)" value="/" />
	</form>

Enter billing numbers

Output