MVC框架与增强

一.什么是MVC

MVC全名是Model View Controller，是模型(model)－视图(view)－控制器(controller)的缩写，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，将业务逻辑聚集到一个部件里面，在改进和个性化定制界面及用户交互的同时，不需要重新编写业务逻辑。

二.编程模式

Model（模型）表示应用程序核心（比如数据库记录列表）

是应用程序中用于处理应用程序数据逻辑的部分，通常模型对象负责在数据库中cun存取数据。

View（视图）显示数据（数据库记录）

是应用程序中处理数据显示的部分，通常视图是依据模型数据创建的。

Controller（控制器）处理输入（写入数据库记录）

是应用程序中处理用户交互的部分，通常控制器负责从视图读取数据，控制用户输入，并向模型发送数据。

三.MVC结构

jsp
ios
android

servlet
action

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

四.自定义MVC工作原理图

五.自定义MVC原理实现（加减乘除）

子控制器接口Action

用来直接处理浏览器发送过来的请求

 package com.mvc.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 Administrator

  *

  */

 public interface Action {

     String  exxecute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException;

 }

实体类Cal

 package com.mvc.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) {

         super();

         this.num1 = num1;

         this.num2 = num2;

     }

     public Cal() {

         super();

     }

 }

子控制器AddCalAction（加）

 package com.mvc.web;

 import java.io.IOException;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import com.mvc.entity.Cal;

 import com.mvc.framework.Action;

 public class AddCalAction implements Action{

     @Override

     public String exxecute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

         String num1=req.getParameter("num1");

         String num2=req.getParameter("num2");

 //        System.out.println(num1);

 //        System.out.println(num2);

         Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

         req.setAttribute("req", cal.getNum1()+cal.getNum2());

         req.getRequestDispatcher("res.jsp").forward(req, resp);

         return null;

     }

 }

在这里减乘除只要更改

子控制器req.setAttribute("req", cal.getNum1()+cal.getNum2());
中的+为- * /则可实现减乘除，提供减法类DelCalAction 乘法类MulCalAction 除法类DivCalAction

中央控制器DispatchrServlet

接收请求,通过请求寻找对应的子控制器

package com.mvc.framework;

import java.io.IOException;

import java.util.HashMap;

import java.util.Map;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.mvc.web.AddCalAction;

import com.mvc.web.DelCalAction;

import com.mvc.web.DivCalAction;

import com.mvc.web.MulCalAction;

/**

 * 中央控制器

 * 作用：接收请求,通过请求寻找对应的子控制器

 * @author Administrator

 *

 */

public class DispatchrServlet extends HttpServlet{

    private Map<String, Action> ActionMap=new HashMap<>();

 public void init() {

  //加

  ActionMap.put("/addCal", new AddCalAction());

  //减

  ActionMap.put("/delCal", new DelCalAction());

  //乘

  ActionMap.put("/mulCal", new MulCalAction());

  //除

   ActionMap.put("/divCal", new DivCalAction());

 }

@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 {

      // TODO Auto-generated method stub

      init();

     String url=req.getRequestURI();

      url=url.substring(url.lastIndexOf("/"),url.lastIndexOf("."));

            Action action = actionMap.get(url);

            action.execute(req, resp);

     }

}

xml配置

 <?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>JavaMVC</display-name>

   <servlet>

   <servlet-name>DispatchrServlet</servlet-name>

   <servlet-class>com.mvc.framework.DispatchrServlet</servlet-class>

   </servlet>

   <servlet-mapping>

   <servlet-name>DispatchrServlet</servlet-name>

   <url-pattern>*.action</url-pattern>

   </servlet-mapping>

 </web-app>

jsp页面代码

 <%@ 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 }/addCal.action"

         }else if (num==2) {

             calForm.action="${pageContext.request.contextPath }/delCal.action"

         }else if (num==3) {

              calForm.action="${pageContext.request.contextPath }/mulCal.action"

         }else if (num==4) {

              calForm.action="${pageContext.request.contextPath }/divCal.action"

         }

           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>

运行结果

六.通过XML对自定义MVC框架进行增强

将子控制器信息动态配置到mvc.xml中
针对MVC框架的结果码进行处理
将一组操作放到一个子控制器中
利用模型驱动接口对mvc框架进行增强
解决框架配置文件的冲突问题

将建模导入到com.mvc.framework中

导入jar包

将子控制器信息动态配置到mvc.xml中

6.1 中央控制器DispatchrServlet

将所有子控制器都汇聚到ConfigModel
配置
反射实例化

 package com.mvc.framework;

 import java.io.IOException;

 import java.util.HashMap;

 import java.util.Map;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import com.mvc.web.AddCalAction;

 import com.mvc.web.DelCalAction;

 import com.mvc.web.DivCalAction;

 import com.mvc.web.MulCalAction;

 /**

  * 中央控制器

  * 作用：接收请求,通过请求寻找对应的子控制器

  * @author Administrator

  *

  */

 public class DispatchrServlet extends HttpServlet{

     //private Map<String, Action> ActionMap=new HashMap<>();

     //第一次改进

     //将所有子控制器都汇聚到ConfigModel

     //在ConfigModel对象中包含了所有子控制器

     private ConfigModel configModel;

     public void init() {

         try {

             configModel=ConfigModelFactory.newInstance();

         } catch (Exception e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

 //        ActionMap.put("/addCal", new AddCalAction());

 //        ActionMap.put("/delCal", new DelCalAction());

 //        ActionMap.put("/mulCal", new MulCalAction());

 //        ActionMap.put("/divCal", new DivCalAction());

     }

     /**

      *

      */

     private static final long serialVersionUID = -7359199881120612454L;

     @Override

     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

     doGet(req, resp);

     }

     @Override

     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

         init();

         String url=req.getRequestURI();

         url=url.substring(url.lastIndexOf("/"), url.lastIndexOf("."));

         //配置

         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");

         }

         //反射实例化

         try {

             Action action =    (Action) Class.forName(actionModel.getType()).newInstance();

             action.exxecute(req, resp);

         } catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

 //        Action action=ActionMap.get(url);

     }

 }

配置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.mvc.web.AddCalAction">

         <forward name="rs" path="/rs.jsp" redirect="false" />

     </action>

     <action path="/delCal" type="com.mvc.web.DelCalAction">

         <forward name="rs" path="/rs.jsp" redirect="false" />

     </action>

     <action path="/mulCal" type="com.mvc.web.MulCalAction">

         <forward name="rs" path="/rs.jsp" redirect="false" />

     </action>

     <action path="/divCal" type="com.mvc.web.DivCalAction">

         <forward name="rs" path="/rs.jsp" redirect="false" />

     </action>

 </config>

工厂模式ConfigModelFactory

 package com.mvc.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();

         }

     }

 }

6.2针对MVC框架的结果码进行处理

中央控制器DispatchrServlet

判断是重定向还是转发
做转发的处理

 package com.mvc.framework;

 import java.io.IOException;

 import java.util.HashMap;

 import java.util.Map;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import com.mvc.web.AddCalAction;

 import com.mvc.web.DelCalAction;

 import com.mvc.web.DivCalAction;

 import com.mvc.web.MulCalAction;

 /**

  * 中央控制器

  * 作用：接收请求,通过请求寻找对应的子控制器

  * @author Administrator

  *

  */

 public class DispatchrServlet extends HttpServlet{

     //private Map<String, Action> ActionMap=new HashMap<>();

     //第一次改进

     //将所有子控制器都汇聚到ConfigModel

     //在ConfigModel对象中包含了所有子控制器

     private ConfigModel configModel;

     public void init() {

         try {

             configModel=ConfigModelFactory.newInstance();

         } catch (Exception e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

 //        ActionMap.put("/addCal", new AddCalAction());

 //        ActionMap.put("/delCal", new DelCalAction());

 //        ActionMap.put("/mulCal", new MulCalAction());

 //        ActionMap.put("/divCal", new DivCalAction());

     }

     /**

      *

      */

     private static final long serialVersionUID = -7359199881120612454L;

     @Override

     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

     doGet(req, resp);

     }

     @Override

     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

         init();

         String url=req.getRequestURI();

         url=url.substring(url.lastIndexOf("/"), url.lastIndexOf("."));

         //配置

         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");

         }

         //反射实例化

         try {

             Action action =    (Action) Class.forName(actionModel.getType()).newInstance();

         String code=action.exxecute(req, resp);

         ForwardModel forwardModel = actionModel.get(code);

         if (forwardModel!=null) {

             String jspPath=forwardModel.getPath();

             //判断是重定向还是转发

             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();

         }

 //        Action action=ActionMap.get(url);

     }

 }

AddCalAction

package com.mvc.web;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.mvc.entity.Cal;

import com.mvc.framework.Action;

public class AddCalAction implements Action{

    @Override

    public String exxecute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        // TODO Auto-generated method stub

        String num1=req.getParameter("num1");

        String num2=req.getParameter("num2");

//        System.out.println(num1);

//        System.out.println(num2);

        Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

        req.setAttribute("req", cal.getNum1()+cal.getNum2());

        //req.getRequestDispatcher("res.jsp").forward(req, resp);

        return "res";

    }

}

DelCalAction

 package com.mvc.web;

 import java.io.IOException;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import com.mvc.entity.Cal;

 import com.mvc.framework.Action;

 public class DelCalAction implements Action{

     @Override

     public String exxecute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

         String num1=req.getParameter("num1");

         String num2=req.getParameter("num2");

 //        System.out.println(num1);

 //        System.out.println(num2);

         Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

         req.setAttribute("req", cal.getNum1()-cal.getNum2());

     //    req.getRequestDispatcher("res.jsp").forward(req, resp);

         return "res";

     }

 }

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.mvc.web.AddCalAction">

        <forward name="res" path="/res.jsp" redirect="false" />

    </action>

    <action path="/delCal" type="com.mvc.web.DelCalAction">

        <forward name="res" path="/res.jsp" redirect="false" />

    </action>

    <action path="/mulCal" type="com.mvc.web.MulCalAction">

        <forward name="res" path="/res.jsp" redirect="false" />

    </action>

    <action path="/divCal" type="com.mvc.web.DivCalAction">

        <forward name="res" path="/res.jsp" redirect="false" />

    </action>

</config>

ForwardModel

 package com.mvc.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;

     }

 }

6.3将一组操作放到一个子控制器中

对子控制器进行增强

ActionSupport增强版子控制器

 package com.mvc.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一用户请求

  * 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 Administrator

  *

  */

 public class ActionSupport implements Action {

     @Override

     public final String exxecute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

         String methodName=req.getParameter("methodName");

         String code = null;

         //class CalAction exends ActionSupport

 //        this在这里指的是CalAction他的一个类实例

         try {

         Method m =    this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);

         m.setAccessible(true);

          code = (String) m.invoke(this, req,resp);

         } catch (NoSuchMethodException | SecurityException | IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

         return code;

     }

 }

将加减乘除方法放入CalAction 类中并继承子控制器ActionSupport

 package com.mvc.web;

 import java.io.IOException;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import com.mvc.entity.Cal;

 import com.mvc.framework.ActionSupport;

 public class CalAction extends ActionSupport{

     public String add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

         String num1=req.getParameter("num1");

         String num2=req.getParameter("num2");

 //        System.out.println(num1);

 //        System.out.println(num2);

         Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

         req.setAttribute("req", cal.getNum1()+cal.getNum2());

         //req.getRequestDispatcher("res.jsp").forward(req, resp);

         return "res";

     }

     public String del(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

         String num1=req.getParameter("num1");

         String num2=req.getParameter("num2");

 //        System.out.println(num1);

 //        System.out.println(num2);

         Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

         req.setAttribute("req", cal.getNum1()-cal.getNum2());

     //    req.getRequestDispatcher("res.jsp").forward(req, resp);

         return "res";

     }

     public String mul(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

         String num1=req.getParameter("num1");

         String num2=req.getParameter("num2");

 //        System.out.println(num1);

 //        System.out.println(num2);

         Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

         req.setAttribute("req", cal.getNum1()*cal.getNum2());

 //        req.getRequestDispatcher("res.jsp").forward(req, resp);

         return "res";

     }

     public String div(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

         String num1=req.getParameter("num1");

         String num2=req.getParameter("num2");

 //        System.out.println(num1);

 //        System.out.println(num2);

         Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

         req.setAttribute("req", cal.getNum1()/cal.getNum2());

 //        req.getRequestDispatcher("res.jsp").forward(req, resp);

         return "res";

     }

 }

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.mvc.web.AddCalAction">-->

         <!--<forward name="res" path="/res.jsp" redirect="false" />-->

     <!--</action>-->

     <!--<action path="/delCal" type="com.mvc.web.DelCalAction">-->

     <!--    <forward name="res" path="/res.jsp" redirect="false" />-->

     <!--</action>-->

     <!--<action path="/mulCal" type="com.mvc.web.MulCalAction">-->

     <!--    <forward name="res" path="/res.jsp" redirect="false" />-->

     <!--</action>-->

     <!--<action path="/divCal" type="com.mvc.web.DivCalAction">-->

     <!--    <forward name="res" path="/res.jsp" redirect="false" />-->

     <!--</action>-->

     <action path="/cal" type="com.mvc.web.CalAction">

         <forward name="res" path="/res.jsp" redirect="false" />

     </action>

 </config>

cal.jsp页面更改

 <%@ 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=mul"

         }else if (num==4) {

              calForm.action="${pageContext.request.contextPath }/cal.action?methodName=div"

         }

           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>

6.4解决框架配置文件的冲突问题

DispatchrServlet 中央控制器加强读取xml

 public void init() {

         try {

             String xmlPath= this.getInitParameter("xmlPath");

             if (xmlPath == null || "".equals(xmlPath)) {

                 configModel=ConfigModelFactory.newInstance();

             }else {

                 configModel=ConfigModelFactory.newInstance(xmlPath);

             }

         } catch (Exception e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

在src下建一个Source Folder 放入一命名不同的xml

配置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>JavaMVC</display-name>

   <servlet>

   <servlet-name>DispatchrServlet</servlet-name>

   <servlet-class>com.mvc.framework.DispatchrServlet</servlet-class>

   <init-param>

   <param-name>xmlPath</param-name>

   <param-value>/mvc.xml</param-value>

   </init-param>

   </servlet>

   <servlet-mapping>

   <servlet-name>DispatchrServlet</servlet-name>

   <url-pattern>*.action</url-pattern>

   </servlet-mapping>

 </web-app>

6.5利用模型驱动接口对mvc框架进行增强

利用ModelDrive接口对java对象赋值（反射读写属性）

ModelDrivern<T>模型驱动接口

 package com.mvc.web;

 /**

  * 模型驱动接口

  * 作用将jsp所有传递过来的参数以及参数值

  * 自动封装到浏览器索要操作的实体类

  * @author Administrator

  *

  */

 public interface ModelDrivern<T> {

      T getModel();

 }

CalAction

 package com.mvc.web;

 import java.io.IOException;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import com.mvc.entity.Cal;

 import com.mvc.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 {

         // TODO Auto-generated method stub

 //        String num1=req.getParameter("num1");

 //        String num2=req.getParameter("num2");

 ////        System.out.println(num1);

 ////        System.out.println(num2);

 //        Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

         req.setAttribute("req", cal.getNum1()+cal.getNum2());

         //req.getRequestDispatcher("res.jsp").forward(req, resp);

         return "res";

     }

     public String del(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

 //        // TODO Auto-generated method stub

 //        String num1=req.getParameter("num1");

 //        String num2=req.getParameter("num2");

 ////        System.out.println(num1);

 ////        System.out.println(num2);

 //        Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

         req.setAttribute("req", cal.getNum1()-cal.getNum2());

     //    req.getRequestDispatcher("res.jsp").forward(req, resp);

         return "res";

     }

     public String mul(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

 //        String num1=req.getParameter("num1");

 //        String num2=req.getParameter("num2");

 ////        System.out.println(num1);

 ////        System.out.println(num2);

 //        Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

         req.setAttribute("req", cal.getNum1()*cal.getNum2());

 //        req.getRequestDispatcher("res.jsp").forward(req, resp);

         return "res";

     }

     public String div(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

 //        String num1=req.getParameter("num1");

 //        String num2=req.getParameter("num2");

 ////        System.out.println(num1);

 ////        System.out.println(num2);

 //        Cal cal=new Cal(Integer.valueOf(num1),Integer.valueOf(num2));

         req.setAttribute("req", cal.getNum1()/cal.getNum2());

 //        req.getRequestDispatcher("res.jsp").forward(req, resp);

         return "res";

     }

     @Override

     public Cal getModel() {

         // TODO Auto-generated method stub

         return cal;

     }

 }

DispatchrServlet

 package com.mvc.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 org.apache.jasper.tagplugins.jstl.core.ForEach;

 import com.mvc.web.AddCalAction;

 import com.mvc.web.DelCalAction;

 import com.mvc.web.DivCalAction;

 import com.mvc.web.ModelDrivern;

 import com.mvc.web.MulCalAction;

 /**

  * 中央控制器

  * 作用：接收请求,通过请求寻找对应的子控制器

  * @author Administrator

  *

  */

 public class DispatchrServlet extends HttpServlet{

     //private Map<String, Action> ActionMap=new HashMap<>();

     //第一次改进

     //将所有子控制器都汇聚到ConfigModel

     //在ConfigModel对象中包含了所有子控制器

     private ConfigModel configModel;

     public void init() {

         try {

             configModel=ConfigModelFactory.newInstance();

         } catch (Exception e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

 //        ActionMap.put("/addCal", new AddCalAction());

 //        ActionMap.put("/delCal", new DelCalAction());

 //        ActionMap.put("/mulCal", new MulCalAction());

 //        ActionMap.put("/divCal", new DivCalAction());

     }

     /**

      *

      */

     private static final long serialVersionUID = -7359199881120612454L;

     @Override

     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

     doGet(req, resp);

     }

     @Override

     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

         // TODO Auto-generated method stub

         init();

         String url=req.getRequestURI();

         url=url.substring(url.lastIndexOf("/"), url.lastIndexOf("."));

         //配置

         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");

         }

         //反射实例化

         try {

             Action action =    (Action) Class.forName(actionModel.getType()).newInstance();

             //调用赋值

             //action就是package com.mvc.framework.CalAction;

             if (action instanceof ModelDrivern) {

                 ModelDrivern mdDrivern=(ModelDrivern) action;

                 //此时的model的所有属性是null的

                 Object model = mdDrivern.getModel();

                 BeanUtils.populate(model, req.getParameterMap());

                 //原理

                 //我们可以将req.getParameterMap();的值通过反射的方式将其塞进model实例

 //                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.exxecute(req, resp);

         ForwardModel forwardModel = actionModel.get(code);

         if (forwardModel!=null) {

             String jspPath=forwardModel.getPath();

             //判断是重定向还是转发

             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 (SecurityException e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         } catch (InvocationTargetException e) {

     // TODO Auto-generated catch block

     e.printStackTrace();

 }

     }

 }

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