在非spring boot程序中， 使用spring cloud config client

spring cloud config能夠集中管理配置文件，不一樣的（spring-boot)應用程序，經過簡單的配置就能夠像使用; 可是普通的spring web application要使用config client卻要費一番周折；

參考： https://github.com/spring-cloud/spring-cloud-config/issues/299

重點：

Well the "normal" way is to use Spring Cloud Config as part of a Spring Boot app. You really should consider doing that at some point.

If you want to try and cobble it together yourself you need a ConfigServicePropertySourceLocatorand you need to apply it to the Environment before the application context is started. How you do that will depend a lot on how you are creating the ApplicationContext (SpringApplication from Spring Boot would be much easier than whatever you are doing probably).

 

咱們是一個spring web application，下面的方法也只是對web app有效；

1. maven 加入spring cloud config client:

<!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-config-client -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-config-client</artifactId>
            <version>1.2.0.RELEASE</version>
        </dependency>

2. 配置web.xml， 讓spring context loader 使用定製過的context;

<context-param>
        <param-name>contextClass</param-name>
        <param-value>com.me.MyConfigurableWebApplicationContext</param-value>
    </context-param>

3. 實現 MyConfigurableWebApplicationContext, 主要的做用是使用自定義的environment;

public class MyConfigurableWebApplicationContext extends XmlWebApplicationContext {


    @Override
    protected ConfigurableEnvironment createEnvironment() {
        return new CloudEnvironment();
    }
}

4. 實現CloundEnvironment

public class CloudEnvironment extends StandardServletEnvironment {

    @Override
    protected void customizePropertySources(MutablePropertySources propertySources) {
        super.customizePropertySources(propertySources);
        try {
            propertySources.addLast(initConfigServicePropertySourceLocator(this));
        } catch (Exception ex) {
            logger.warn("failed to initialize cloud config environment", ex);
        }
    }

    private PropertySource<?> initConfigServicePropertySourceLocator(Environment environment) {
        ConfigClientProperties configClientProperties = new ConfigClientProperties(environment);
        configClientProperties.setUri("http://localhost:8888");
        configClientProperties.setName("myapp");
        configClientProperties.setLabel("master");
        ConfigServicePropertySourceLocator configServicePropertySourceLocator =
            new ConfigServicePropertySourceLocator(configClientProperties);
        return configServicePropertySourceLocator.locate(environment);
    }

}

5. 測試, 在server端配置cloud.config=true, 若是有效，那麼這裏應該可以獲得true；

@Value("${cloud.config: false}")
    public void setCloudConfig(boolean cloudConfig) {
        this.cloudConfig = cloudConfig;
    }