自定义mvc

1. 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

2. MVC结构

M
实体域模型(名词)
过程域模型(动词)

V
jsp/ios/android

C
servlet/action

注1：不能跨层调用
注2：只能出现由上而下的调用

3. 自定义MVC工作原理图

	*.action           调度           截取*（请求路径名） 处理具体业务逻辑
   JSP -----------> Servlet(中央控制器）--------------------->Action（子控制器）--->Model(Dao、DB)

4. 工具类

4.1 实体类

package com.leiyuanlin.entity;

/**
 * 计算器的实体类
 * @author 2018101801
 *
 */
public class Cal {
//	数字1
	private int num1;
//	数字2
	private int num2;
	
	public Cal() {
	}
	
	public Cal(int num1, int num2) {
		this.num1 = num1;
		this.num2 = 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;
	}
	
}

4.2 mvc.xml

<?xml version="1.0" encoding="UTF-8"?>
	<!--
		config标签:可以包含0~N个action标签
	-->
<config>
	<!--
		action标签:可以饱含0~N个forward标签
		path:以/开头的字符串,并且值必须唯一 非空
		type:字符串,非空
	-->
	<action path="/regAction" type="test.RegAction">
		<!--
			forward标签:没有子标签; 
			name:字符串,同一action标签下的forward标签name值不能相同 ;
			path:以/开头的字符串
			redirect:只能是false|true,允许空,默认值为false
		-->
		<forward name="failed" path="/reg.jsp" redirect="false" />
		<forward name="success" path="/login.jsp" redirect="true" />
	</action>

	<action path="/loginAction" type="test.LoginAction">
		<forward name="failed" path="/login.jsp" redirect="false" />
		<forward name="success" path="/main.jsp" redirect="true" />
	</action>
	
	<action path="/calAction" type="com.zking.web.CalAction">
		<forward name="rs" path="/rs.jsp" redirect="false" />
	</action>
</config>

4.3 ConfigModel

package com.leiyuanlin.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 ActionModel

package com.leiyuanlin.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);
	}
	
}

4.5 ForwardModel

package com.leiyuanlin.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 ConfigModelFactory

package com.leiyuanlin.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();
		}
	}
}

5. 通过XML对自定义mvc框架进行增强

主控制器：

package com.leiyuanlin.framework;

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


/**
 * 中央控制器
 * 	作用：接受请求，通过请求寻找处理请求对应的子控制器
 * @author 2018101801
 *
 */
public class DispatcherServlet extends HttpServlet {
	private static final long serialVersionUID = -560410324520863823L;
//	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());
		try {
			String xmlPath = this.getInitParameter("xmlPath");
			if(xmlPath == null || "".equals(xmlPath)) {
				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();
//		/web_mvc/addCal.action ---> /addCal
		url = url.substring(url.lastIndexOf("/"), url.lastIndexOf("."));
//		Action action = actionMap.get(url);
		ActionModel actionModel = configModel.get(url);
		if(actionModel == null) {
			throw new RuntimeException("你没有配置action标签，找不到对应的子控制器来处理浏览器发送的请求");
		}
		
		try {
//			Action action = new AddCalAction();
			Action action = (Action) Class.forName(actionModel.getType()).newInstance();

//			action=com.leiyuanlin.web.CalAction
			if(action instanceof ModelDrivern) {
				ModelDrivern modelDrivern = (ModelDrivern) action;
//				此时的model的所有属性值是null的
				Object model = modelDrivern.getModel();
				BeanUtils.populate(model, req.getParameterMap());
				
//				拿值的原理(底层源码)
//				我们可以将req.getParameterMap()的值通过所反射的方式将其塞进model的实例中
				/*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) {
					try {
						Field field = clz.getField(entry.getKey());
						field.setAccessible(true);
						field.set(model, value);
					} catch (NoSuchFieldException | SecurityException e) {
						e.printStackTrace();
					}
				}*/
			}
			
			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) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			e.printStackTrace();
		}
		
	}
}

模型驱动接口:

package com.leiyuanlin.framework;
/**
 * 模型驱动接口
 * 	作用：将jsp所有传递过来的参数以及参数值都自动封装到浏览器所要操作的实体类中
 * @author 2018101801
 *
 */
public interface ModelDrivern<T> {
	T getModel();
}

子控制器：

package com.leiyuanlin.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 2018101801
 *
 */
public interface Action {
	String execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException;
}

增强版子控制器:

package com.leiyuanlin.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;

/**
 * 增强版子控制器
 * 	原来的子控制器只能处理一个用户请求
 * 	有时候，用户请求是多个，但是都是操作同一张表，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 2018101801
 *
 */
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 method = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
			method.setAccessible(true);
			code = (String) method.invoke(this, req,resp);
		} catch (NoSuchMethodException | SecurityException | IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
			e.printStackTrace();
		}
		return code;
	}

}

CalAction:

package com.leiyuanlin.web;

import java.io.IOException;

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

import com.leiyuanlin.entity.Cal;
import com.leiyuanlin.framework.ActionSupport;
import com.leiyuanlin.framework.ModelDrivern;

public class CalAction extends ActionSupport implements ModelDrivern<Cal>{
	private Cal cal = new Cal();
//	加法
	public String add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		req.setAttribute("res", cal.getNum1()+cal.getNum2());
		return "res";
	}
	
//	减法
	public String del(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		req.setAttribute("res", cal.getNum1()-cal.getNum2());
		return "res";
	}
	
//	mult	乘法
	public String mult(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		req.setAttribute("res", cal.getNum1()*cal.getNum2());
		return "res";
	}
	
//	divi	除法
	public String divi(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());
		return "res";
	}

	@Override
	public Cal getModel() {
		return cal;
	}
	
}

mvc.xml:

<?xml version="1.0" encoding="UTF-8"?>

<config>
	<action path="/cal" type="com.leiyuanlin.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="${pageContext.request.contextPath }/cal.action?methodName=mult";
		}else if(num==4){
			calForm.action="${pageContext.request.contextPath }/cal.action?methodName=divi";
		}
		calForm.submit();
	}
</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(结果页面):

web.xml:

测试效果：

结果：

感谢观看！