SpringBoot中读取配置的七种方法总结

@Component
public class MyBean {
    @Value("${some.key1}")
    private String someKey1;

     @Value("${some.key2:defaultVal}")
    private String someKey2;

    public void initSomeKey3(@Value("${some.key3}")String key){
        ...
    }
}

@Component
@ConfigurationProperties(prefix = "some")
public class SomeProperties {
    private String key;
    private List<String> values;

    // ... getters and setters
}

@Component
public class MyBean {
    private final Environment environment;

    @Autowired
    public MyBean(Environment environment) {
        this.environment = environment;
    }

    public void someMethod() {
        String someKey = environment.getProperty("some.key");
        // ...
    }
}

// 通过获取Environment 
@Component
public class MyEnvironmentAware implements EnvironmentAware {

    private Environment env;
    
    @Override
    public void setEnvironment(Environment environment) {
        this.env = environment;
    }

    public String getKey() {
        return env.getProperty("some.key");
    }
}

/**
 * 绑定自定义properties配置
*/
@Data
@Configuration
@PropertySource("classpath:custom.properties")
public class MyPropertiesComponent {
    @Value("${some.key}")
    private String someKey;

    // ...
}

@Service
public class ConfigService {
    private MyConfig config;

    @PostConstruct
    public void init() throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        InputStream inputStream = new ClassPathResource("config.json").getInputStream();
        this.config = mapper.readValue(inputStream, MyConfig.class);
    }

    // ... 使用config的方法
}

import org.springframework.boot.CommandLineRunner;  
import org.springframework.stereotype.Component;  
  
@Component  
public class CommandLineAppStartupRunner implements CommandLineRunner {  
  
    @Override  
    public void run(String... args) throws Exception {  
        if (args.length > 0) {  
            System.out.println("接收到命令行参数：");  
            for (String arg : args) {  
                System.out.println(arg);  
            }  
        } else {  
            System.out.println("没有接收到命令行参数。");  
        }  
    }  
}

java -jar your-spring-boot-app.jar arg1 arg2 arg3

@Value("#{systemProperties['some.key'] ?: 'default'}")
private String someKey;