自定义MVC二

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

我们需要导入四个包

 还有5个工具类

ActionModel

package com.zjj.beike;

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);
    }
    
}

ConfigModel

package com.zjj.beike;

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);
    }
    
}

ConfigModelFactory

package com.zjj.beike;

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("config.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();
        }
    }
}

ForwardModel

package com.zjj.beike;

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;
    }

}

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="/Cal" type="com.web.AddCalAction">
        <forward name="res" path="/res.jsp" redirect="false" />
    </action>
</config>

下面来看下我们的中央控制器

private static final long serialVersionUID = 1L;
    //private Map<String , IAction> actionMap = new HashMap<>();
    
    //在configModel对象包含了所有的子控制信息
    private ConfigModel configModel;
    
    
    public void init() {
    //    actionMap.put("/addCal", new AddCalAction());
        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();
        }
        
    }
    
    
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
        
    }
    
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        init();
        String url= request.getRequestURI();
//        /***/addCal.action
        url = url.substring(url.lastIndexOf("/"), url.lastIndexOf("."));
//        IAction 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处理浏览器发送的请求");
//        }
     try {
        
         
        Action action=(Action) Class.forName(actionModel.getType()).newInstance();
        //action就是com.zking.web.CalAction
        if(action instanceof ModelDrivern) {
            ModelDrivern modelDrivern=(ModelDrivern)action;
            //此时的model的所有属性值都是null的
            Object model = modelDrivern.getModel();
            BeanUtils.populate(model, request.getParameterMap());
        }
        
        
        
        //返回码
        String code = action.execute(request, response);
        ForwardModel forwardModel = actionModel.get(code);
       if(forwardModel!=null) {
           String jspPath = forwardModel.getPath();
          if("false".equals(forwardModel.getRedirect())) {
              //做转发的处理
              request.getRequestDispatcher(jspPath).forward(request, response);
          }
          else {
              response.sendRedirect(request.getContextPath()+jspPath);
          }
       }
     } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
//        try {
//            action.execute(req, resp);
//        } catch (Exception e) {
//            // TODO Auto-generated catch block
//            e.printStackTrace();
//        }
        
        
    }

以及我们的xml的配置

<?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>MVC</display-name>
  <servlet>
  <servlet-name>DispatcherServlet</servlet-name>
  <servlet-class>com.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>

还有一个子控制器

作用：用来直接处理浏览器发送过来的请求。

public interface Action {
    
 String execute(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, Exception;
 
 
}

现在再来看下增强版的

原来的子控制器只能处理一个用户请求

作用：将一组相关的操作放到一个Action中

public class ActionSupport implements Action{

    @Override
    public final String execute(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException, Exception {
     String menthodName=request.getParameter("menthodName");
     //this值的是CalAction它的一个类实例
     String code=null;
     Method m=this.getClass().getDeclaredMethod(menthodName,HttpServletRequest.class,HttpServletResponse.class);
     m.setAccessible(true);    
     code = (String) m.invoke(this,request,response);
        
        return code;
    }

}

 利用ModelDrivern接口对Java对象进行赋值(反射读写属性)

public interface ModelDrivern<T> {
  T getModel();
}

接下来就是实现业务逻辑的类CalAction

public class CalAction extends ActionSupport implements ModelDrivern<Cal>{
   private Cal cal=new Cal();

    public String add(HttpServletRequest request, HttpServletResponse response) throws Exception, Exception {    
        request.setAttribute("res", cal.getNum1()+cal.getNum2());
        return "res";
    }

    public String reduce(HttpServletRequest request, HttpServletResponse response) throws Exception, Exception {    
        request.setAttribute("res", cal.getNum1()-cal.getNum2());
        return "res";
    }
    
    public String ride(HttpServletRequest request, HttpServletResponse response) throws Exception, Exception {    
        request.setAttribute("res", cal.getNum1()*cal.getNum2());
        return "res";
    }
    
    public String except(HttpServletRequest request, HttpServletResponse response) throws Exception, Exception {    
        request.setAttribute("res", cal.getNum1()/cal.getNum2());
        return "res";
    }
    
    
    @Override
    public Cal getModel() {
        // TODO Auto-generated method stub
        return cal;
    }

    
    
}

最后就是JSP页面了

<%@ 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="${pageContext.request.contextPath}/Cal.action?menthodName=add";
    }
    else if(num==2){
        calForm.action="${pageContext.request.contextPath}/Cal.action?menthodName=reduce";
    }
    else if(num==3){
        calForm.action="${pageContext.request.contextPath}/Cal.action?menthodName=ride";
    }
    else if(num==4){
        calForm.action="${pageContext.request.contextPath}/Cal.action?menthodName=except";
    }
    calForm.submit();
}

</script>
</head>
<body>
<form name="calForm" method="post" action="">
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>

我选乘把

结果