spring MVC basic

1、MVC&&Spring MVC

.mvc的就核心思想是业务数据抽取同业务数据呈现相分离

.View,视图层，为用户提供UI，重点关注数据的呈现

.model,业务数据的信息表示，关注支撑业务信息构成（对象类），通常是多个业务实体的组合

.controller,调用业务逻辑产生合适的数据（model）,传递数据给视图层用于呈现

Mvc是一种架构模式，程序分层，分工合作

spirng mvc 概念：

DispatcherServlet(前端控制器)

浏览器的请求通过DispacherServlet的分发到达一个合理的Controller，来生成业务数据model，再通过DispatcherServlet进行传递到View层

DispatcherServlet使用HandlerAdapter适配器.适配到相应的Controller

HandlerIntercaptor,拦截器,afterCompletion/postHandle/preHandle

HandlerMapping：

1.help DispatcherServlet to get the right cotroller

2.Wrap controller with HandlerInterceptor

HandlerExecutionChain:

preHandle-->Controoler method-->postHandle-->afterCompletion

ModelAndView

ViewResovle视图解析器

导入jar包

配置spring mvc 核心过滤器web.xml

<servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:application_spring_mvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

apllication.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans
        xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:tx="http://www.springframework.org/schema/tx"
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:mvc="http://www.springframework.org/schema/mvc"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-4.0.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">

    <context:component-scan base-package="com.nyan"/>
    <mvc:annotation-driven/>
    <!-- 視圖解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
    </bean>

    <!-- 对静态资源的访问 -->
    <mvc:resources mapping="/images/**" location="/WEB-INF/images" cache-period="31556926"/>
</beans>

Controller层：

package com.nyan.action;

import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

/**
 * Created by Administrator on 2017/3/11 0011.
 */
@Controller
@Scope("prototype")
@RequestMapping("/user")
public class UserAction {

    @RequestMapping(value = "/save",method = RequestMethod.GET)
    public ModelAndView save(String name,String password){
        System.out.println("後台處理數據:"+name);
        ModelAndView modelAndView = new ModelAndView();
　　　　 //返回saveUserSuccess.jsp页面
        modelAndView.setViewName("saveUserSuccess");
        modelAndView.addObject("msg","save successfully");
        return modelAndView;
    }
}

view层：

<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2017/3/11 0011
  Time: 12:05
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
  <form action="./user/save" method="get">
    <input type="text" name="name" value="nyan"/>
    <input type="password" name="password" value="passw0rd"/>
    <input type="submit" value="submit"/>
  </form>
  </body>
</html>

submit后调用./user/save,通过RequestMapping找到对应的action，进行业务逻辑处理返回一个modelAndView，通过视图解析器解析返回的modelAndView对象返回对应Dev视图。