spring boot web 第一个项目新建

1.idea 专业版

2.maven3.6

3.springboot

创建项目：

1. new project :

 下一步：

 选取web下一步：

 由于新建是没有webapp但是可以自己新建：

 web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

<!-- 前端控制器 dispatch-servlet -->
    <servlet>
        <!-- 默认读取的是webapp/web-inf/<servlet-name>-servlet.xml，可以自定义-->
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--自定义springmvc配置文件的位置-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
        <!--tomcat 启动之前创建对象-->
        <load-on-startup>1</load-on-startup>
    </servlet>
<!-- url-pattern 可以有两种值1：*.jsp, 2.使用 /-->
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>

    <!--    listener-->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

</web-app>

　　

springmvc.xml配置：

<?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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">


    <context:component-scan base-package="com.example.demo.controller"/>

    <!--3：配置JSP 显示ViewResolver-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
        <property name="prefix" value="/WEB-INF/views/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

　　

controller/UserController.class

package com.example.demo.controller;


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;

@Controller
public class UserController {

    @RequestMapping(value="/show.do",method = RequestMethod.GET)
    public ModelAndView  modelAndView(){
        ModelAndView  modelAndView = new ModelAndView();
        modelAndView.addObject("msg","hello world！！！");
        modelAndView.setViewName("/WEB-INF/views/show.jsp");
        return modelAndView;
    }

}