mvc的思想：各司其职
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
2、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)
3、自定义mvc原理图
4. 自定义MVC工作原理图理解
主控制动态调用子控制器调用完成具体的业务逻辑
（火车、控制台、 车轨）
请求、主控制器、子控制器
主控制器：DispatcherServlet
package com.framework;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.management.RuntimeErrorException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.web.AddCalAction;
import com.web.DelCalAction;
/**
* 中央控制器
* 作用：接受请求，通过请求寻找处理请求的对应的子控制器
* @author 2018111801
*
*/
public class DispatcherServlet extends HttpServlet{
/**
*
*/
private static final long serialVersionUID = 723689920988912828L;
// 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());
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();
// }
}
然后是我们的子控制器：Action
package com.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过来的请求
* @author 2018111801
*
*/
public interface Action {
String execute(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, Exception;
}
子控制器附属调优：ActionSupport
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;
}
}
具体方法：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;
}
}
写一个驱动接口
public interface ModelDrivern<T> {
T getModel();
}
ActionModel
package com.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);
}
}
文件解析工厂：ConfigModelFatory
package com.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();
}
}
}
ForwardModel
package com.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;
}
}
mvc.xml配置
<?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.web.AddCalAction">
<forward name="res" path="/res.jsp" redirect="false" />
</action>
</config>
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>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>
jsp页面
<%@ 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>
到这里就完成了，接下来我们看下测试结果
1*1
原文：https://www.cnblogs.com/BAYOUA/p/11084980.html