springboot官方文檔
https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#_working_with_spring_boot
maven依賴
spring-boot-starter-parent
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>myproject</artifactId>
<version>0.0.1-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.RELEASE</version>
</parent>
<!-- Additional lines to be added here... -->
</project>
web依賴
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
啓動類和接口
@RestController
@EnableAutoConfiguration
public class HelloWorldApp {
@RequestMapping("/")
String home() {
return "Hello World!";
}
public static void main(String[] args) throws Exception {
SpringApplication.run(HelloWorldApp.class, args);
}
}
註解解釋
@RestController
@RestController = @Controller + @ResponseBody
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Controller //springmvc的註解
@ResponseBody //springmvc的註解
public @interface RestController {
@AliasFor(
annotation = Controller.class
)
String value() default "";
}
官方文檔解釋
The @RestController and @RequestMapping annotations are Spring MVC annotations. (They are not specific to Spring Boot.)
解釋： @RestController 和 @RequestMapping 是springmvc的註解，沒什麼特殊性
@EnableAutoConfiguration
This annotation tells Spring Boot to “guess” how you want to configure Spring, based on the jar dependencies that you have added. Since spring-boot-starter-web added Tomcat and Spring MVC, the auto-configuration assumes that you are developing a web application and sets up Spring accordingly.
@EnableAutoConfiguration 猜測地給開發者配置好有關springmvc、tomcat、spring方面的配置。也就是會自動配置好springmvc、tomcat、spring的一些配置
啓動服務和訪問接口
啓動main方法，控制檯打印：
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.1.0.RELEASE)
2018-11-21 15:03:33.622 INFO 75693 --- [ main] com.yimingkeji.helloworld.HelloWorldApp : Starting HelloWorldApp on yangzhenlongdeMacBook-Pro.local with PID 75693 (/Users/yangzhenlong/projs/my/yimingkeji/springboot/helloword/target/classes started by yangzhenlong in /Users/yangzhenlong/projs/my/yimingkeji/springboot)
2018-11-21 15:03:33.626 INFO 75693 --- [ main] com.yimingkeji.helloworld.HelloWorldApp : No active profile set, falling back to default profiles: default
2018-11-21 15:03:34.499 INFO 75693 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2018-11-21 15:03:34.516 INFO 75693 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2018-11-21 15:03:34.516 INFO 75693 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/9.0.12
2018-11-21 15:03:34.522 INFO 75693 --- [ main] o.a.catalina.core.AprLifecycleListener : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [/Users/yangzhenlong/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.]
2018-11-21 15:03:34.581 INFO 75693 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2018-11-21 15:03:34.582 INFO 75693 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 917 ms
2018-11-21 15:03:34.604 INFO 75693 --- [ main] o.s.b.w.servlet.ServletRegistrationBean : Servlet dispatcherServlet mapped to [/]
2018-11-21 15:03:34.607 INFO 75693 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-11-21 15:03:34.608 INFO 75693 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-11-21 15:03:34.608 INFO 75693 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'formContentFilter' to: [/*]
2018-11-21 15:03:34.608 INFO 75693 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2018-11-21 15:03:34.763 INFO 75693 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2018-11-21 15:03:34.933 INFO 75693 --- [ main]
o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2018-11-21 15:03:34.936 INFO 75693 --- [ main] com.yimingkeji.helloworld.HelloWorldApp : Started HelloWorldApp in 1.727 seconds (JVM running for 2.849)
日誌中看到 項目啓動端口(prot)爲8080，啓動根路徑(path)爲' '
瀏覽器或者http客戶端（如postman）訪問 localhost:8080
Hello World!
使用jar包啓動
在pom.xml依賴中添加spring-boot-maven-plugin插件
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
在終端shell或者Terminal中執行命令：
$ mvn package
在項目target目錄下會生成jar包：
啓動jar包
$ java -jar target/helloword-1.0.0-SNAPSHOT.jar
2018-11-21 15:12:35.077 INFO 75841 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2018-11-21 15:12:35.355 INFO 75841 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2018-11-21 15:12:35.359 INFO 75841 --- [ main] com.yimingkeji.helloworld.HelloWorldApp : Started HelloWorldApp in 2.382 seconds (JVM running for 2.838)
訪問 localhost:8080
Hello World!
按 Ctrl + C 結束服務。
使用mvn啓動
$ mvn spring-boot:run