手摸手-第一次spring经历舒服了

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手摸手带走你的第一次，写springboot项目

通过spring.io生成初始代码，配置如下

下载好会得到一个.zip文件，解压导入IDEA就可以开始了，这是基础的项目结构

让我们打开src/main/java/geektime/spring/hello/hellospring/HelloSpringApplication.java，修改成如下代码

package geektime.spring.hello.hellospring;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class HelloSpringApplication {

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

	@RequestMapping("/hello")
	public String hello() {
		return "Hello Spring";
	}
}

接着运行我们修改的代码，运行成功后，console会打印如下信息

/Library/Java/JavaVirtualMachines/jdk-15.0.1.jdk/Contents/Home/bin/java -javaagent:/Applications/IntelliJ IDEA CE.app/Contents/lib/idea_rt.jar=55568:/Applications/IntelliJ IDEA CE.app/Contents/bin -Dfile.encoding=UTF-8 -classpath /Users/lidean/Downloads/hello-spring/target/classes:/Users/lidean/.m2/repository/org/springframework/boot/spring-boot-starter-actuator/2.5.0/spring-boot-starter-actuator-2.5.0.jar:/Users/lidean/.m2/repository/org/springframework/boot/spring-boot-starter/2.5.0/spring-boot-starter-2.5.0.jar:/Users/lidean/.m2/repository/org/springframework/boot/spring-boot/2.5.0/spring-boot-2.5.0.jar:/Users/lidean/.m2/repository/org/springframework/boot/spring-boot-autoconfigure/2.5.0/spring-boot-autoconfigure-2.5.0.jar:/Users/lidean/.m2/repository/org/springframework/boot/spring-boot-starter-logging/2.5.0/spring-boot-starter-logging-2.5.0.jar:/Users/lidean/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar:/Users/lidean/.m2/repository/ch/qos/logback/logback-core/1.2.3/logback-core-1.2.3.jar:/Users/lidean/.m2/repository/org/apache/logging/log4j/log4j-to-slf4j/2.14.1/log4j-to-slf4j-2.14.1.jar:/Users/lidean/.m2/repository/org/apache/logging/log4j/log4j-api/2.14.1/log4j-api-2.14.1.jar:/Users/lidean/.m2/repository/org/slf4j/jul-to-slf4j/1.7.30/jul-to-slf4j-1.7.30.jar:/Users/lidean/.m2/repository/jakarta/annotation/jakarta.annotation-api/1.3.5/jakarta.annotation-api-1.3.5.jar:/Users/lidean/.m2/repository/org/yaml/snakeyaml/1.28/snakeyaml-1.28.jar:/Users/lidean/.m2/repository/org/springframework/boot/spring-boot-actuator-autoconfigure/2.5.0/spring-boot-actuator-autoconfigure-2.5.0.jar:/Users/lidean/.m2/repository/org/springframework/boot/spring-boot-actuator/2.5.0/spring-boot-actuator-2.5.0.jar:/Users/lidean/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.12.3/jackson-databind-2.12.3.jar:/Users/lidean/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.12.3/jackson-annotations-2.12.3.jar:/Users/lidean/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.12.3/jackson-core-2.12.3.jar:/Users/lidean/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jsr310/2.12.3/jackson-datatype-jsr310-2.12.3.jar:/Users/lidean/.m2/repository/io/micrometer/micrometer-core/1.7.0/micrometer-core-1.7.0.jar:/Users/lidean/.m2/repository/org/hdrhistogram/HdrHistogram/2.1.12/HdrHistogram-2.1.12.jar:/Users/lidean/.m2/repository/org/latencyutils/LatencyUtils/2.0.3/LatencyUtils-2.0.3.jar:/Users/lidean/.m2/repository/org/springframework/boot/spring-boot-starter-web/2.5.0/spring-boot-starter-web-2.5.0.jar:/Users/lidean/.m2/repository/org/springframework/boot/spring-boot-starter-json/2.5.0/spring-boot-starter-json-2.5.0.jar:/Users/lidean/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jdk8/2.12.3/jackson-datatype-jdk8-2.12.3.jar:/Users/lidean/.m2/repository/com/fasterxml/jackson/module/jackson-module-parameter-names/2.12.3/jackson-module-parameter-names-2.12.3.jar:/Users/lidean/.m2/repository/org/springframework/boot/spring-boot-starter-tomcat/2.5.0/spring-boot-starter-tomcat-2.5.0.jar:/Users/lidean/.m2/repository/org/apache/tomcat/embed/tomcat-embed-core/9.0.46/tomcat-embed-core-9.0.46.jar:/Users/lidean/.m2/repository/org/apache/tomcat/embed/tomcat-embed-el/9.0.46/tomcat-embed-el-9.0.46.jar:/Users/lidean/.m2/repository/org/apache/tomcat/embed/tomcat-embed-websocket/9.0.46/tomcat-embed-websocket-9.0.46.jar:/Users/lidean/.m2/repository/org/springframework/spring-web/5.3.7/spring-web-5.3.7.jar:/Users/lidean/.m2/repository/org/springframework/spring-beans/5.3.7/spring-beans-5.3.7.jar:/Users/lidean/.m2/repository/org/springframework/spring-webmvc/5.3.7/spring-webmvc-5.3.7.jar:/Users/lidean/.m2/repository/org/springframework/spring-aop/5.3.7/spring-aop-5.3.7.jar:/Users/lidean/.m2/repository/org/springframework/spring-context/5.3.7/spring-context-5.3.7.jar:/Users/lidean/.m2/repository/org/springframework/spring-expression/5.3.7/spring-expression-5.3.7.jar:/Users/lidean/.m2/repository/org/slf4j/slf4j-api/1.7.30/slf4j-api-1.7.30.jar:/Users/lidean/.m2/repository/org/springframework/spring-core/5.3.7/spring-core-5.3.7.jar:/Users/lidean/.m2/repository/org/springframework/spring-jcl/5.3.7/spring-jcl-5.3.7.jar geektime.spring.hello.hellospring.HelloSpringApplication

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.5.0)

2021-06-01 23:15:57.484  INFO 81444 --- [           main] g.s.h.h.HelloSpringApplication           : Starting HelloSpringApplication using Java 15.0.1 on MacBook-Pro-9.local with PID 81444 (/Users/lidean/Downloads/hello-spring/target/classes started by lidean in /Users/lidean/Downloads/hello-spring)
2021-06-01 23:15:57.488  INFO 81444 --- [           main] g.s.h.h.HelloSpringApplication           : No active profile set, falling back to default profiles: default
2021-06-01 23:15:58.610  INFO 81444 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2021-06-01 23:15:58.626  INFO 81444 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-06-01 23:15:58.626  INFO 81444 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.46]
2021-06-01 23:15:58.685  INFO 81444 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-06-01 23:15:58.685  INFO 81444 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1073 ms
2021-06-01 23:15:59.156  INFO 81444 --- [           main] o.s.b.a.e.web.EndpointLinksResolver      : Exposing 1 endpoint(s) beneath base path '/actuator'
2021-06-01 23:15:59.195  INFO 81444 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2021-06-01 23:15:59.208  INFO 81444 --- [           main] g.s.h.h.HelloSpringApplication           : Started HelloSpringApplication in 2.658 seconds (JVM running for 3.251)
2021-06-01 23:15:59.254  INFO 81444 --- [           main] o.s.b.a.ApplicationAvailabilityBean      : Application availability state LivenessState changed to CORRECT
2021-06-01 23:15:59.256  INFO 81444 --- [           main] o.s.b.a.ApplicationAvailabilityBean      : Application availability state ReadinessState changed to ACCEPTING_TRAFFIC

2021-06-01 23:22:00.698  INFO 81444 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-06-01 23:22:00.698  INFO 81444 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2021-06-01 23:22:00.699  INFO 81444 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms

从上面输出的信息我们可以知道Tomcat初始化部署在了8080端口，下面我们来访问试试

// 调用我们定义的router
$ curl http://127.0.0.1:8080/hello                            
Hello Spring%
// 记得我们之前生成项目使用的actuator依赖，用于检查项目是否健康
// 若出现DOWN，我们访问url就会失败
$ curl http://127.0.0.1:8080/actuator/health
{"status":"UP"}%        

让Maven替我们打个包

$ mvn clean packeage -Dmaven.test.skip
zsh: command not found: mvn

没命令。。。上链接

若有，可跳过

作者用的是macOs的zsh，需要做下面几步

# 给文件夹权限
$ sudo chown -R root:wheel Downloads/apache-maven*
# 移动
$ mv Downloads/apache-maven* /opt/apache-maven
# 打开zsh配置文件
$ nano ~/.zshrc
# 新增命令，写入~/.zshrc
$ export PATH=$PATH:/opt/apache-maven/bin

搞定后control+X回车搞定~ 重启下终端，检查mvn版本即可

$ zsh
# 检查Maven
$ mvn -version
Apache Maven 3.8.1 (05c21c65bdfed0f71a2f2ada8b84da59348c4c5d)
Maven home: /opt/apache-maven
Java version: 15.0.1, vendor: Oracle Corporation, runtime: /Library/Java/JavaVirtualMachines/jdk-15.0.1.jdk/Contents/Home
Default locale: zh_CN_#Hans, platform encoding: UTF-8
OS name: "mac os x", version: "10.15.6", arch: "x86_64", family: "mac"

继续继续，maven打包我们的代码

$ mvn clean package -Dmaven.test.skip 
[INFO] Scanning for projects...
[INFO] 
[INFO] -----------------< geektime.spring.hello:hello-spring >-----------------
[INFO] Building hello-spring 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:3.1.0:clean (default-clean) @ hello-spring ---
[INFO] Deleting /Users/lidean/Downloads/hello-spring/target
[INFO] 
[INFO] --- maven-resources-plugin:3.2.0:resources (default-resources) @ hello-spring ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] Copying 1 resource
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ hello-spring ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /Users/lidean/Downloads/hello-spring/target/classes
[INFO] 
[INFO] --- maven-resources-plugin:3.2.0:testResources (default-testResources) @ hello-spring ---
[INFO] Not copying test resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ hello-spring ---
[INFO] Not compiling test sources
[INFO] 
[INFO] --- maven-surefire-plugin:2.22.2:test (default-test) @ hello-spring ---
[INFO] Tests are skipped.
[INFO] 
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ hello-spring ---
[INFO] Building jar: /Users/lidean/Downloads/hello-spring/target/hello-spring-0.0.1-SNAPSHOT.jar
[INFO] 
[INFO] --- spring-boot-maven-plugin:2.5.0:repackage (repackage) @ hello-spring ---
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  2.965 s
[INFO] Finished at: 2021-06-02T00:02:00+08:00
[INFO] ------------------------------------------------------------------------

可以看到生成的两个.jar包，一个18M一个却3.0K，因为前者有我们所有的依赖(该.jar包可执行)，后者是原始的包

下面我们可以通过java -jar去执行这个jar包，可以看到也是暴露在8080端口，我们的程序可以作为一个单独的进程运行在里面

结束语：如果遇到什么疑问或者建议的，可直接留言评论！作者看到会马上一一回复

如果觉得小白此文章不错或对你有所帮助，期待你的一键三连💫！❤️ ni ~