学习springMVC-最少jar包及简单搭建

1.jar包下载

http://repo.spring.io/release/org/springframework/spring/4.2.4.RELEASE/

2.新建web项目，保留web.xml.

3.配置web.xml文件(/WEB-INF/下)：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">

  <servlet>
    <servlet-name>SpringMVC</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!-- 配置SpringMVC下的配置文件位置及名称 -->
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:springmvc.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>
</web-app>

4.配置springmvc.xml文件（在/src下 classpath即为/src）

<?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: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.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">

        <!-- 自动扫描controller包下的所有类，使其认为是spring mvc的控制器 路径即为类路径 -->
        <context:component-scan base-package="com.test.springmvc"></context:component-scan>


        <!-- 配置视图解析器 如何把handler 方法返回值解析为实际的物理视图  根据控制器返回的字符串拼接成jsp路径：/WEB-INF/jsp/xx.jsp -->
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name = "prefix" value="/WEB-INF/jsp/"></property>
            <property name = "suffix" value = ".jsp"></property>
        </bean>
</beans>

5.导入jar包

（1）直接启动tomcat:
警告: No mapping found for HTTP request with URI [/SpringTest/] in DispatcherServlet with name ‘SpringMVC’
因为在web.xml中引入了org.springframework.web.servlet.DispatcherServlet，所以需要导入spring-mvc包
（2）再来：
java.lang.ClassNotFoundException: org.springframework.context.ApplicationContextAware
导入spring-context包
（3）再启动：
java.lang.ClassNotFoundException: org.springframework.beans.factory.Aware
导入spring-bean包
（4）再来：
java.lang.ClassNotFoundException: org.springframework.core.env.EnvironmentCapable
导入spring-core包
（5）继续：
Caused by: java.lang.NoClassDefFoundError: org/springframework/web/context/request/async/CallableProcessingInterceptor
导入spring-web包
（6）再来：
Caused by: java.lang.NoClassDefFoundError: Lorg/apache/commons/logging/Log;
导入commons-logging包
（7）继续：
Caused by: java.lang.NoClassDefFoundError: org/springframework/aop/TargetSource
导入spring-aop包
（8）接着：
java.lang.NoClassDefFoundError: org/springframework/expression/ParserContext
导入spring-expression包，再启动就不报错了。
所以最小jar包是
SpringMVC最小jar包

6.编写控制器：

package com.test.springmvc;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class Show {
    @RequestMapping("/welcome")
    public String welcome() {
        return "welcome";
    }
}

7.编写welcome.jsp页面（在/WEB-INF/jsp/下）

<%@ 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>
欢迎！
</body>
</html>