一文带你了解SpringBoot中启动参数的各种用法

java -jar myapp.jar --server.port=8081

java -jar myapp.jar --server.port=8081 --spring.application.name=myapp

server.port=8082
spring.application.name=myapp
logging.level.root=INFO

server:
  port: 8082
spring:
  application:
    name: myapp
logging:
  level:
    root: INFO

export SERVER_PORT=9090
export SPRING_APPLICATION_NAME=MySpringApp
java -jar myapp.jar

set SERVER_PORT=9090
java -jar myapp.jar

java -Dspring.profiles.active=prod -jar myapp.jar

String profile = System.getProperty("spring.profiles.active");
System.out.println("当前环境：" + profile);

java -Xmx512m -Xms256m -jar myapp.jar

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/config")
public class ConfigController {

    @Value("${server.port}")
    private String serverPort;

    @Value("${spring.application.name}")
    private String appName;

    @GetMapping("/info")
    public String getConfigInfo() {
        return "App: " + appName + ", Running on Port: " + serverPort;
    }
}

import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class EnvController {

    private final Environment env;

    public EnvController(Environment env) {
        this.env = env;
    }

    @GetMapping("/env")
    public String getEnvInfo() {
        return "Profile: " + env.getProperty("spring.profiles.active") +
               ", Server Port: " + env.getProperty("server.port");
    }
}

@GetMapping("/jvm")
public String getJvmParams() {
    return "JVM Param: " + System.getProperty("custom.param", "默认值");
}

java -Dcustom.param=myValue -jar myapp.jar

JVM Param: myValue