Spring Boot：启动、自动配置与 Profiles

<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>3.4.9</version>
    <relativePath/>
  </parent>
  <groupId>study.qinghuan</groupId>
  <artifactId>first-boot</artifactId>
  <version>1.0.0</version>
  <properties><java.version>17</java.version></properties>
  <dependencies><dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
  </dependency></dependencies>
  <build><plugins><plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
  </plugin></plugins></build>
</project>

package study.qinghuan;

import java.util.Map;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args); // 参数传给启动流程和环境处理。
    }
    @GetMapping("/hello")
    public Map<String, String> hello() {
        return Map.of("message", "Hello Java"); // Web 配置负责将对象序列化成 JSON。
    }
}

server.address=127.0.0.1
server.port=8080

server.port=8081

mvn -version
mvn package
java -jar target/first-boot-1.0.0.jar
# 第二个终端：curl.exe http://127.0.0.1:8080/hello

# 结束上一轮后，使用 dev 配置：
java -jar target/first-boot-1.0.0.jar --spring.profiles.active=dev
# 第二个终端：curl.exe http://127.0.0.1:8081/hello

# 再次结束后，命令行覆盖 dev 的端口：
java -jar target/first-boot-1.0.0.jar --spring.profiles.active=dev --server.port=8090
# 第二个终端：curl.exe http://127.0.0.1:8090/hello