自定义mvc流程与概念
1.什么是MVC?
MVC全名:Model View Controller,其中Model(模型层)、View(视图层)、Controller(控制层)
它是一种软件设计典范,用于业务逻辑处理、数据、界面显示分离,
两种常用模式:
model1:jsp+jdbc
model2:mvc
2.三层架构和MVC的区别?
三层架构是一个经典的分层思想,将开发模式分为三层,每个人专注自己擅长模块即可
MVC是一种设计模式,其目的是让html和业务逻辑分开
3.MVC结构
V(视图层) --》JSP/HTML/freemarker
C(控制层) --》Servlet/Action/Controller
M(模型层) --》entity、dao
entity:实体域模型(名词)
dao:过程域模型(动词)
1不能跨层调用
2只能由上往下进行调用;View -> Controller -> Model
4.自定义MVC工作原理图
第一张个人理(仅供参考)
完整流程图
5.MVC小测试
中央控制器
package com.tanle.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.tanle.mvc.action.AsmdAction;
import com.tanle.mvc.action.HelloAction;
/**
* 自定义mvc中的中央控制器
* @author tanle
*
*/
public class ActionServlet extends HttpServlet{
private Map<String, Action> map;
@Override
public void init() throws ServletException {
// TODO Auto-generated method stub
/**
* 初始化
*/
map=new HashMap<String, Action>();
map.put("/helloAction", new HelloAction());
map.put("/asmdAction", new AsmdAction());
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
//1。获取请求路径
///J2EE_MVC1/*.action
String requestURI = req.getRequestURI();
//找到最后一个斜杠
int start=requestURI.lastIndexOf("/");
//找到.action
int end=requestURI.lastIndexOf(".action");
//2.截取请求路径中的 J2EE_MVC1/*.action /*部分
String actionName = requestURI.substring(start, end);
//3.通过截取路径中的actionName找到对应的子控制器
//Action action = map.get(actionName);等同于 Action action = new Action();
Action action = map.get(actionName);
//4.执行execute方法
action.execute(req, resp);
}
}
控制器的子类
package com.tanle.mvc.framework;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* 控制器的父类 完成具体的业务逻辑
* @author tanle
*
*/
public abstract class Action{
public abstract String execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException;
}
逻辑代码处理块
package com.tanle.mvc.action;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.tanle.mvc.framework.Action;
public class AsmdAction extends Action{
@Override
public String execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
String num1 = req.getParameter("num1");
String num2 = req.getParameter("num2");
String count= req.getParameter("count");
int num3=0;
if("+".equals(count)) {
num3+=Integer.parseInt(num1)+Integer.parseInt(num2);
}else if("-".equals(count)) {
num3+=Integer.parseInt(num1)-Integer.parseInt(num2);
}else if("*".equals(count)) {
num3+=Integer.parseInt(num1)*Integer.parseInt(num2);
}else if("/".equals(count)){
num3+=Integer.parseInt(num1)/Integer.parseInt(num2);
}
req.setAttribute("num3", num3);
req.getRequestDispatcher("close.jsp").forward(req, resp);
return null;
}
}
计算界面
<%@ 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>
</head>
<body>
<form action="asmdAction.action" method="post">
num1:<input type="text" name="num1" /><br/>
num2:<input type="text" name="num2" /><br/>
<input type="submit" value="+" name="count"/>
<input type="submit" value="-" name="count"/>
<input type="submit" value="*" name="count"/>
<input type="submit" value="/" name="count"/>
</form>
</body>
</html>
计算结果
<%@ 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>
<h2>计算结果:${num3 }</h2>
</body>
</html>
6.总结
理解性去学习这个自定义mvc,有什么不足的地方欢迎大家指正,谢谢观看.