SpringBoot 的参数配置示例全解析

server.port=8081
spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=root
spring.datasource.password=secret
logging.level.com.example.demo=debug

server:
  port: 8081
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mydb
    username: root
    password: secret
logging:
  level:
    com.example.demo: debug

java -jar yourapp.jar --server.port=8888 --spring.datasource.url=jdbc:mysql://prod-server:3306/proddb

spring:
  profiles:
    active: dev # 默认激活开发环境

@Component
public class MyComponent {
    @Value("${server.port}")
    private int serverPort;
    @Value("${app.message: Hello Default}") // 使用冒号指定默认值
    private String message;
    // ... 
}

app:
  user:
    name: "Alice"
    age: 30
    email: "alice@example.com"
    hobbies:
      - reading
      - hiking

@Component
@ConfigurationProperties(prefix = "app.user") // 前缀是 app.user
@Data // Lombok 注解，自动生成 getter/setter
// 或者也可以手动写 getter 和 setter
public class UserProperties {
    private String name;
    private Integer age;
    private String email;
    private List<String> hobbies;
}

@Service
public class MyService {
    @Autowired
    private UserProperties userProperties;
    public void doSomething() {
        System.out.println("User name: " + userProperties.getName());
        System.out.println("User hobbies: " + userProperties.getHobbies());
    }
}

# 服务器配置
server:
  port: 8080
  servlet:
    context-path: /api # 应用上下文路径
# 数据源配置
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver
  # JPA 配置
  jpa:
    hibernate:
      ddl-auto: update # 生产环境不要用 create-drop 或 update
    show-sql: true
# 日志配置
logging:
  level:
    root: info
    org.springframework.web: debug
    com.example: trace
  file:
    name: logs/myapp.log # 输出到文件
# 自定义配置
myapp:
  feature:
    enabled: true
    api-url: https://api.example.com