SpringMVC HelloWorld

1. 创建Maven工程：可以参考这个链接

2. pom注入依赖的jar包

<dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-logging/commons-logging -->
    <dependency>
      <groupId>commons-logging</groupId>
      <artifactId>commons-logging</artifactId>
      <version>1.1.1</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <version>5.1.12.RELEASE</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.1.12.RELEASE</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>5.1.12.RELEASE</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-expression -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-expression</artifactId>
      <version>5.1.12.RELEASE</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>5.1.12.RELEASE</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.1.12.RELEASE</version>
    </dependency>
  </dependencies>

3. 配置web.xml文件

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/applicationContext.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 配置DispatcherServlet的一个初始化参数：配置SpringMVC配置文件的位置和名称-->
        <!-- 实际上也可以不通过contextConfigLocation 来配置SpringMVC的配置文件，而使用默认的-->
        <!-- 默认的配置文件为：/WEB-INF/<servlet-name>-servlet.xml -->
<!--        <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>dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

4. 配置dispatcher-servlet.xml文件

<?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">

    <!-- 配置自动扫描的包-->
    <context:component-scan base-package="com.sangyu.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-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
</beans>

5. 编写HelloWorld.java文件

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

@Controller
public class HelloWorld {
    /**
     * 1. 使用@RequestMapping 注解来映射请求的URL
     * 2. 返回值会通过视图解析器解析为实际的物理视图，对于InternalResourceViewResolver
     * 视图解析器，会做如下的解析：
     * 通过prefix + returnVal + suffix，得到实际的物理视图，然后做转发操作
     * /WEB-INF/views/success.jsp
     * @return
     */
    @RequestMapping("/helloworld")
    public String hello(){
        System.out.println("hello world");
        return "success";
    }
}

6. 编写index.jsp

<html>
<body>
<h2>Hello World!</h2>
<a href="helloworld">Hello World!</a>
</body>
</html>

7. 创建success.jsp文件

<body>
<h4> success page</h4>
</body>

8. 配置tomcat，可以参考这个链接，tomcat配置完成后如下图：
   

9. 整个项目的目录结构

10. 执行tomcat

    
    

11. HelloWorld 运行流程图