自定义MVC

程序员文章站 2022-05-30 22:43:15

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什么是MVC
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

核心思想：各司其职
MVC结构

V
jsp/ios/android
C
servlet/action
M
实体域模型(名词)
过程域模型(动词)
```
注1：不能跨层调用
注2：只能出现由上而下的调用
```
自定义MVC工作原理图

自定义MVC
4.工具类
4.1 实体类:

package com.wupeng.entity;

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

}

4.2 ActionModel:

package com.wupeng.framework;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

/**
 * 用来描述action标签
 * @author Administrator
 *
 */
public class ActionModel implements Serializable{

	private static final long serialVersionUID = 6145949994701469663L;
	
	private Map<String, ForwardModel> forwardModels = new HashMap<String, ForwardModel>();
	
	private String path;
	
	private String type;
	
	public String getPath() {
		return path;
	}

	public void setPath(String path) {
		this.path = path;
	}

	public String getType() {
		return type;
	}

	public void setType(String type) {
		this.type = type;
	}

	public void put(ForwardModel forwardModel){
		forwardModels.put(forwardModel.getName(), forwardModel);
	}
	
	public ForwardModel get(String name){
		return forwardModels.get(name);
	}
	
}

4.3 ConfigModel：

package com.wupeng.framework;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

/**
 * 用来描述config标签
 * @author Administrator
 *
 */
public class ConfigModel implements Serializable{

	private static final long serialVersionUID = -2334963138078250952L;
	
	private Map<String, ActionModel> actionModels = new HashMap<String, ActionModel>();
	
	public void put(ActionModel actionModel){
		actionModels.put(actionModel.getPath(), actionModel);
	}
	
	public ActionModel get(String name){
		return actionModels.get(name);
	}
	
}

4.4 ConfigModelFactory：

package com.wupeng.framework;

import java.io.InputStream;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

public class ConfigModelFactory {
	private ConfigModelFactory() {

	}

	private static ConfigModel configModel = null;

	public static ConfigModel newInstance() throws Exception {
		return newInstance("mvc.xml");
	}

	/**
	 * 工厂模式创建config建模对象
	 * 
	 * @param path
	 * @return
	 * @throws Exception
	 */
	public static ConfigModel newInstance(String path) throws Exception {
		if (null != configModel) {
			return configModel;
		}

		ConfigModel configModel = new ConfigModel();
		InputStream is = ConfigModelFactory.class.getResourceAsStream(path);
		SAXReader saxReader = new SAXReader();
		Document doc = saxReader.read(is);
		List<Element> actionEleList = doc.selectNodes("/config/action");
		ActionModel actionModel = null;
		ForwardModel forwardModel = null;
		for (Element actionEle : actionEleList) {
			 actionModel = new ActionModel();
			actionModel.setPath(actionEle.attributeValue("path"));
			actionModel.setType(actionEle.attributeValue("type"));
			List<Element> forwordEleList = actionEle.selectNodes("forward");
			for (Element forwordEle : forwordEleList) {
				forwardModel = new ForwardModel();
				forwardModel.setName(forwordEle.attributeValue("name"));
				forwardModel.setPath(forwordEle.attributeValue("path"));
				forwardModel.setRedirect(forwordEle.attributeValue("redirect"));
				actionModel.put(forwardModel);
			}

			configModel.put(actionModel);
		}

		return configModel;
	}
	
	public static void main(String[] args) {
		try {
			ConfigModel configModel = ConfigModelFactory.newInstance();
			ActionModel actionModel = configModel.get("/loginAction");
			ForwardModel forwardModel = actionModel.get("failed");
			System.out.println(actionModel.getType());
			System.out.println(forwardModel.getPath());
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

4.5 ForwardModel：

package com.wupeng.framework;

import java.io.Serializable;

/**
 * 用来描述forward标签
 * @author Administrator
 *
 */
public class ForwardModel implements Serializable {

	private static final long serialVersionUID = -8587690587750366756L;

	private String name;
	private String path;
	private String redirect;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getPath() {
		return path;
	}

	public void setPath(String path) {
		this.path = path;
	}

	public String getRedirect() {
		return redirect;
	}

	public void setRedirect(String redirect) {
		this.redirect = redirect;
	}

}

4.6 mvc.xml:

<?xml version="1.0" encoding="UTF-8"?>
	<!--
		config标签:可以包含0~N个action标签
	-->
<config>
	<action path="/addCal" type="com.wupeng.web.AddCalAction">
		<forward name="res" path="/res.jsp" redirect="false" />
	</action>
	<action path="/delCal" type="com.wupeng.web.DelCalAction">
		<forward name="res" path="/res.jsp"  />
	</action>
	<action path="/multiplyCal" type="com.wupeng.web.MultiplyCalAction">
		<forward name="res" path="/res.jsp" redirect="false" />
	</action>
	<action path="/divisionCal" type="com.wupeng.web.DivisionCalAction">
		<forward name="res" path="/res.jsp" redirect="false" />
	</action>
</config>

5 . 通过XML对自定义mvc框架进行增强

*控制器：

package com.wupeng.framework;

import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

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

import org.apache.commons.beanutils.BeanUtils;

import com.wupeng.entity.Cal;
import com.wupeng.web.AddCalAction;
import com.wupeng.web.DelCalAction;
import com.wupeng.web.DivisionCalAction;
import com.wupeng.web.ModelDrivern;
import com.wupeng.web.MultiplyCalAction;
/**
 * *控制器
 * 作用:接受请求,通过请求寻找处理请求的对应自控器
 * @author wupeng
 *
 */
public class DispatcherServlet extends HttpServlet {
	private static final long serialVersionUID = 523027225232320832L;
//	private Map<String, Action> ActionMap=new HashMap<>();
//	在configModel对象中包含了所有的子控制器信息
	private ConfigModel configModel;
	public  void init() {
//		ActionMap.put("/addCal", new AddCalAction());
//		ActionMap.put("/delCal", new DelCalAction());
//		ActionMap.put("/multiplyCal", new MultiplyCalAction());
//		ActionMap.put("/divisionCal", new DivisionCalAction());
//		5.1 将Action的信息配置到xml(反射实例化)
//		解决了在框架代码中去改动，以便于完成客户需求，这个是不合理的
		try {
			String xmlPath=this.getInitParameter("xmlPath");
			if(xmlPath==null||xmlPath.equals("") ) {
				configModel=ConfigModelFactory.newInstance();
			}else {
				configModel=ConfigModelFactory.newInstance(xmlPath);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	@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();
	String url=req.getRequestURI();
//	mvc/addCal.action
	url=url.substring(url.lastIndexOf("/"),url.lastIndexOf("."));
//	Action action = ActionMap.get(url);
	ActionModel actionModel = configModel.get(url);
	try {
		Action action=(Action) Class.forName(actionModel.getType()).newInstance();
		if(action instanceof ModelDrivern) {
			ModelDrivern modelDrivern=(ModelDrivern) action;
//			此时的model的所有属性全是空的
			Object model = modelDrivern.getModel();
			BeanUtils.populate(model, req.getParameterMap());
//			我们可以将req.getParameterMap()的值通过反射的方式将其塞进model实例中
//			Map<String, String[]> parameterMap = req.getParameterMap();
//			Set<Entry<String, String[]>> entrySet = parameterMap.entrySet();
//			Class<? extends Object> clz = model.getClass();
//			for (Entry<String, String[]> entry : entrySet) {
//				Field field = clz.getField(entry.getKey());
//				field.set(model, entry.getValue());
//			}
			
		}
		
		String code=action.execute(req, resp);
		ForwardModel forwardModel = actionModel.get(code);
		if(forwardModel!=null) {
			String jspPath = forwardModel.getPath();
			if("false".equals(forwardModel.getRedirect())) {
//				做转发的处理
				req.getRequestDispatcher(jspPath).forward(req, resp);
			}else {
				resp.sendRedirect(req.getContextPath()+jspPath);
			}
		}
		
	} catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	} catch (InvocationTargetException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	
	}
	
}

模型驱动接口:

package com.wupeng.web;
/**
 * 模型驱动接口
 * 作用是将jsp所有传递过来的参数都自动封装到浏览器所要操作的实体类中
 * @author wupeng
 *
 */
public interface ModelDrivern<T> {
	 T getModel();
}

子控制器：

package com.wupeng.framework;

import java.io.IOException;

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

/**
 * 子控制器
 * 作用:用来直接处理浏览器发送过来的请求
 * @author wupeng
 *
 */
public interface Action {
String execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException;
}

增强版子控制器:

package com.wupeng.framework;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * 增强版的子控制器
 * 原来的子控制器只能处理一个请求
 * 有时候,用户请求是多个,但是都是操作同一个实体类或同一个张表,那么原有的子控制器代码编写繁琐
 * 增强版的作用就是
 * 将一组相关的操作放到一个Action中
 * @author wupeng
 *
 */
public class ActionSupport implements Action {

	
	@Override
	public final String execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		String  methodName=req.getParameter("methodName");
		String code =null;
		
		//		this在这里指的是CalAction它的一个类实例
		try {
			Method m = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
			code= (String) m.invoke(this,req,resp);
			m.setAccessible(true);
		} catch (NoSuchMethodException | SecurityException | IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return code;
	}

}

CalAction:

package com.wupeng.web;

import java.io.IOException;

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

import com.wupeng.entity.Cal;
import com.wupeng.framework.ActionSupport;

public class CalAction extends ActionSupport implements ModelDrivern<Cal> {
	private Cal cal=new Cal();
	public String add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//		String num1=req.getParameter("num1");
//		String num2=req.getParameter("num2");
//		Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));
		req.setAttribute("res",cal.getNum1()+cal.getNum2());
//		req.getRequestDispatcher("res.jsp").forward(req, resp);
		return "res";
	}
	public String del(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//		String num1=req.getParameter("num1");
//		String num2=req.getParameter("num2");
//		Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));
		req.setAttribute("res",cal.getNum1()-cal.getNum2());
//		req.getRequestDispatcher("res.jsp").forward(req, resp);
		return "res";
	}
	public String division(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//		String num1=req.getParameter("num1");
//		String num2=req.getParameter("num2");
//		Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));
		req.setAttribute("res",cal.getNum1()/cal.getNum2());
//		req.getRequestDispatcher("res.jsp").forward(req, resp);
		return "res";
	}
	public String multiply(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//		String num1=req.getParameter("num1");
//		String num2=req.getParameter("num2");
//		Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));
		req.setAttribute("res",cal.getNum1()*cal.getNum2());
//		req.getRequestDispatcher("res.jsp").forward(req, resp);
		return "res";
	}
	@Override
	public Cal getModel() {
		return cal;
	}
}

mvc.xml:

<?xml version="1.0" encoding="UTF-8"?>
	<!--
		config标签:可以包含0~N个action标签
	-->
<config>
	<action path="/cal" type="com.wupeng.web.CalAction">
		<forward name="res" path="/res.jsp" redirect="false" />
	</action>
</config>

cal.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>
<script type="text/javascript">
	function doSub(num) {
		if(num==1){
			calForm.action="${pageContext.request.contextPath}/cal.action?methodName=add"
		}else if(num==2){
			calForm.action="${pageContext.request.contextPath}/cal.action?methodName=del"
		}else if(num==3){
			calForm.action="${pageContext.request.contextPath}/cal.action?methodName=multiply"
		}else if(num==4){
			calForm.action="${pageContext.request.contextPath}/cal.action?methodName=division"
		}
	}
</script>
</head>
<body>
<form name="calForm"  action="" method="post">
	num1:<input type="text" name="num1"><br>
	num2:<input type="text" name="num2"><br>
	<button onclick="doSub(1)">+</button>
	<button onclick="doSub(2)">-</button>
	<button onclick="doSub(3)">*</button>
	<button onclick="doSub(4)">/</button>
</form>
</body>
</html>

res.jsp（结果）：

<%@ 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>
结果:${res}
</body>
</html>

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>mvc</display-name>
<servlet>
	<servlet-name>dispatcherServlet</servlet-name>
	<servlet-class>com.wupeng.framework.DispatcherServlet</servlet-class>
	<init-param>
		<param-name>xmlPath</param-name>
		<param-value>/mvc.xml</param-value>
		
	</init-param>
</servlet>
<servlet-mapping>
	<servlet-name>dispatcherServlet</servlet-name>
	<url-pattern>*.action</url-pattern>
</servlet-mapping>
</web-app>

结果:
自定义MVC
加 +

减 -

乘 *

除 /

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