springboot项目一般使用application.yml配置文件，数据库信息写在里面，做部署时，各个项目可能密码要求不一样需要修改密码，每次修改密码都要打包就比较麻烦，可以增加个外部配置文件进行处理，具体如下：

1、修改Application.java

@ComponentScan(basePackages = {"com.**.x"})
@EnableFeignClients(basePackages = {"com.**.x"})
@SpringBootApplication
@Slf4j
@EnableTransactionManagement
public class ApiApplication {private static final Logger logger = LoggerFactory.getLogger(PdsApiApplication.class);public static void main(String[] args) {//SpringApplication.run(ApiApplication.class, args);SpringApplication application = new SpringApplication(ApiApplication.class);// Load external properties file if it existsString externalConfigPath = "config.properties";Resource resource = new FileSystemResource(externalConfigPath);if (resource.exists()) {logger.info("配置文件存在");try {Properties properties = PropertiesLoaderUtils.loadProperties(resource);PropertySource<?> propertySource = new PropertiesPropertySource("externalConfig", properties);application.addInitializers(context -> {ConfigurableEnvironment environment = context.getEnvironment();environment.getPropertySources().addFirst(propertySource);});} catch (IOException e) {e.printStackTrace();}}else{logger.info("配置文件不存在");}// Run the applicationapplication.run(args);}}

这段代码检查 config.properties 文件是否存在，如果存在则加载该配置文件并将其添加到 Spring Boot 的环境中。这确保了外部配置会覆盖 application.yml 中的相应配置项。 

2、配置文件config.properties如下：

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/mysql?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&tinyInt1isBit=false&useSSL=false&serverTimezone=GMT%2B8&allowMultiQueries=true
spring.datasource.username=root
spring.datasource.password=xxx
spring.datasource.main.url=jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&tinyInt1isBit=false&useSSL=false&serverTimezone=GMT%2B8&allowMultiQueries=true
spring.datasource.main.username=root
spring.datasource.main.password=xxx