SpringMVC初识

1 SpringMVC的概述

• Spring为展现层提供的基于MVC设计理念的优秀的web框架，是目前最主流的MVC框架之一。
• Spring3.0后面全面超过Struts2，成为了最优秀的MVC框架。
• Spring MVC通过一套MVC注解，让POJO成为处理请求的控制器，而无须实现任何接口。
• 支持REST风格的URL请求。
• 采用了松散耦合的可插拔组件结构，比其他MVC框架更具有扩展性和灵活性。

2 SpringMVC的HellloWorld

2.1 环境搭建

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>5.2.1.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aspects</artifactId>
    <version>5.2.0.RELEASE</version>
</dependency>
<dependency>
    <groupId>aopalliance</groupId>
    <artifactId>aopalliance</artifactId>
    <version>1.0</version>
</dependency>
<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.9.4</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.2.1.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>5.2.1.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.2.1.RELEASE</version>
</dependency>

2.2 在web.xml中配置DispatcherServlet

• 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">
    <!--
      配置DispatcherServlet:
      DispatcherServlet默认加载的是/WEB-INF/<servlet-name>-Servlet.xml的Spring配置文件，来启动WEB层的Spring容器。
      可以通过init-param中的contextConfigLocation来自定义配置文件的位置和名称
     -->
    <servlet>
        <servlet-name>dispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath*:springMVC.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

2.3 创建SpringMVC的配置文件

• springMVC.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:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-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/aop
        http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx-4.0.xsd ">

    <!-- 配置自动扫描的包 -->
    <context:component-scan base-package="com.sunxiaping.springmvc"></context:component-scan>

    <!-- 配置视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>

</beans>

2.4 创建Handler

• HelloWorldController.java

package com.sunxiaping.springmvc.controller;

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

@Controller
public class HelloWorldController {

    @RequestMapping(value = "/helloWorld")
    public String helloWorld() {
        System.out.println("你好，世界");
        return "success";
    }

}

2.5 在WEB-INF目录下创建views目录，并在views目录下创建success.jsp

• success.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    成功啦
</body>
</html>