手动创建一个Spring Boot 2.x项目
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spring boot 2.1.9版本quick start参考文档地址：https://docs.spring.io/spring-boot/docs/2.1.9.RELEASE/reference/html/getting-started-first-application.html#getting-started-first-application-pom
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新建一个Maven项目
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pom.xml文件中增加导入依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.9.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
这时项目上有个小红叉，这是由于项目可能有一些必要的组件没有更新，解决方法如下：
// 在项目上右键，选择Maven->Update Project...
// 可以看到小红叉消失了
- 书写启动类
package com.fei;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
/**
* Created by zxf on 2019年10月17日
*/
// @RestController注解是@Controller和@ResponseBody两个注解的组合
@RestController
@EnableAutoConfiguration
public class SpringBootDemoApplication {
/**
* 对外提供一个/服务
* @return
*/
@RequestMapping("/")
public String home() {
return "Hello World!";
}
// Spring Boot应用启动类
public static void main(String[] args) {
SpringApplication.run(SpringBootDemoApplication.class, args);
}
}
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直接像运行Java程序那样就可以了，然后在浏览器输入
http://localhost:8080/访问即可看到Hello world! -
控制台打印的日志信息如下
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.1.9.RELEASE)
2019-10-17 23:27:00.528 INFO 9320 --- [ main] com.fei.SpringBootDemoApplication : Starting SpringBootDemoApplication on Dell-pc with PID 9320 (E:\Developing\workspace-sts\spring-boot-demo\target\classes started by Dell in E:\Developing\workspace-sts\spring-boot-demo)
2019-10-17 23:27:00.542 INFO 9320 --- [ main] com.fei.SpringBootDemoApplication : No active profile set, falling back to default profiles: default
2019-10-17 23:27:02.268 INFO 9320 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2019-10-17 23:27:02.348 INFO 9320 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2019-10-17 23:27:02.352 INFO 9320 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.26]
2019-10-17 23:27:02.568 INFO 9320 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2019-10-17 23:27:02.568 INFO 9320 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1945 ms
2019-10-17 23:27:02.930 INFO 9320 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2019-10-17 23:27:03.190 INFO 9320 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2019-10-17 23:27:03.195 INFO 9320 --- [ main] com.fei.SpringBootDemoApplication : Started SpringBootDemoApplication in 3.371 seconds (JVM running for 5.42)
2019-10-17 23:28:54.760 INFO 9320 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2019-10-17 23:28:54.761 INFO 9320 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2019-10-17 23:28:54.771 INFO 9320 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 10 ms
从日志信息我们可以知道以下信息：
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所用Spring Boot的版本为：2.1.9.RELEASE
:: Spring Boot :: (v2.1.9.RELEASE) -
当前运行的Spring Boot进程PID：
with PID 9320 -
当前应用使用的是内嵌的tomcat，并且运行在8080端口上：
o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
