新建maven工程并添加依赖

新建maven项目，并下载依赖，pom.xml如下

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.3.RELEASE</version>
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

创建DemoApplication

创建DemoApplication类，并新建main方法

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

运行DemoApplication.main()
控制台打印日志：

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.2.3.RELEASE)

2021-10-28 15:55:16.084  INFO 22244 --- [           main] com.example.demo.DemoApplication         : Starting DemoApplication on DESKTOP-72NINQO with PID 22244 (D:\learning\SpringBoot\demo\target\classes started by felix in D:\learning\SpringBoot\demo)
2021-10-28 15:55:16.092  INFO 22244 --- [           main] com.example.demo.DemoApplication         : No active profile set, falling back to default profiles: default
2021-10-28 15:55:17.244  INFO 22244 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2021-10-28 15:55:17.261  INFO 22244 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-10-28 15:55:17.261  INFO 22244 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.30]
2021-10-28 15:55:17.346  INFO 22244 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-10-28 15:55:17.347  INFO 22244 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1185 ms
2021-10-28 15:55:17.529  INFO 22244 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2021-10-28 15:55:17.741  INFO 22244 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2021-10-28 15:55:17.745  INFO 22244 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 2.171 seconds (JVM running for 3.406)
2021-10-28 15:55:18.380  INFO 22244 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-10-28 15:55:18.380  INFO 22244 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2021-10-28 15:55:18.388  INFO 22244 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 8 ms

一个SpringBoot web项目就运行起来了，此时访问http://localhost:8080，会得到一个404响应

图片.png

新建org.example.demo.controller.HelloController.java

package com.example.demo.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping
public class HelloController {
    @GetMapping("/hello")
    public Object hello() {
        return "hello springboot!";
    }
}

此时工程结构如下：

图片.png

图片.png

一个基于SpringBoot的Web工程就搭建完成了