前言：
在springboot项目中，一般的配置文件都在resource/config下面，它可以以两种方式存在，一种是yml,一种是properties方式。
当运维和开发分开的时候，比如连接mysql数据库生产上的时候，运维不会告诉你账户和密码，需要将配置文件放到固定的目录下，运维自己去配置。这样就需要配置文件外置。
当配置文件外置的时候，他是在项目启动的时候，自己去加载配置文件。下面请看实现。
1. 需要增加一个文件
spring.factories，这个文件里面配置启动的时候需要初始化的信息
org.springframework.boot.env.EnvironmentPostProcessor=cn.fintecher.pangolin.service.common.config.AutoConfigEnvironmentPostProcessor
2. 在AutoConfigEnvironmentPostProcessor这个类中增加如下代码
package cn.fintecher.pangolin.service.common.config;import cn.fintecher.pangolin.common.utils.AutoConfigEnvironmentUtil;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.boot.SpringApplication;import org.springframework.boot.env.EnvironmentPostProcessor;import org.springframework.boot.env.PropertySourceLoader;import org.springframework.core.annotation.Order;import org.springframework.core.env.ConfigurableEnvironment;import org.springframework.core.io.support.PathMatchingResourcePatternResolver;import org.springframework.core.io.support.ResourcePatternResolver;import org.springframework.core.io.support.SpringFactoriesLoader;import java.util.List;@Order(1)public class AutoConfigEnvironmentPostProcessor implements EnvironmentPostProcessor { private final Logger logger = LoggerFactory.getLogger(AutoConfigEnvironmentPostProcessor.class); private final ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver(); private final List<PropertySourceLoader> propertySourceLoaders; public AutoConfigEnvironmentPostProcessor() { super(); this.propertySourceLoaders = SpringFactoriesLoader.loadFactories(PropertySourceLoader.class, getClass().getClassLoader()); } @Override public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) { AutoConfigEnvironmentUtil.postProcessEnvironment(environment, application, propertySourceLoaders, resourcePatternResolver, logger); }}公共方法：
public static void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application, List<PropertySourceLoader> propertySourceLoaders, ResourcePatternResolver resourcePatternResolver, Logger logger) { String[] activeProfiles = environment.getActiveProfiles(); for (String activeProfile : activeProfiles) { if (Objects.equals(activeProfile, "swagger")) continue; for (PropertySourceLoader loader : propertySourceLoaders) { for (String fileExtension : loader.getFileExtensions()) { if (!fileExtension.equals("yml")) continue; String applicationLocal = ResourceUtils.CLASSPATH_URL_PREFIX + "/config/application.yml"; try { Resource applicationResource = resourcePatternResolver.getResource(applicationLocal); List<PropertySource<?>> applactionYML = loader.load(ResourceUtils.CLASSPATH_URL_PREFIX + "/config/application.yml", applicationResource); applactionYML.stream().forEach(environment.getPropertySources()::addLast); } catch (IOException e) { e.printStackTrace(); } String path = (String) environment.getPropertySources().get("applicationConfig: [classpath:/config/application.yml]").getProperty("spring.config.location"); String location = path + "/application-" + activeProfile + "." + fileExtension; try { Resource[] resources = resourcePatternResolver.getResources(location); for (Resource resource : resources) { List<PropertySource<?>> propertySources = loader.load(resource.getFilename(), resource); if (null != propertySources && !propertySources.isEmpty()) { propertySources.stream().forEach(environment.getPropertySources()::addLast); } } } catch (IOException e) { logger.error(e.getMessage(), e); } } } }}
3. 在代码中获取了spring.config.location这个配置文件，这个配置文件在application.yml中配置如下
spring: application: name: common-service config: location: @profile.properties@
@profile.properties@ 取的是pom文件中的<profile.properties>file:d:/tomcat/profiles/${project.artifactId}/properties</profile.properties>
这样这个配置文件就可以放在任何目录下面。
4. 其他信息比如logger日志也需要放在外面，在application.yml增加如下配置即可。
ps: 不需要改动的配置信息都可以配置在application.yml中。
logging: config: @profile.properties@/logback-spring.xml
5. 可以试试。
