有没有关于使用Apache ZooKeeper来分发Java应用程序配置的详细文档，特别是Spring服务的使用案例？
像许多云服务用户一样，我需要更改数量不定的Java服务的配置，最好在运行时无需重新启动服务。
更新
最终，我编写了一些代码，将ZooKeeper节点作为属性文件加载，并创建了一个ResourcePropertySource并将其插入到Spring上下文中。请注意，这将不会反映出上下文启动后ZooKeeper节点中的更改。
public class ZooKeeperPropertiesApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
private static final Logger logger = LoggerFactory.getLogger(ZooKeeperPropertiesApplicationContextInitializer.class);
private final CuratorFramework curator;
private String projectName;
private String projectVersion;
public ZooKeeperPropertiesApplicationContextInitializer() throws IOException {
logger.trace("Attempting to construct CuratorFramework instance");
RetryPolicy retryPolicy = new ExponentialBackoffRetry(10, 100);
curator = CuratorFrameworkFactory.newClient("zookeeper", retryPolicy);
curator.start();
}
/**
* Add a primary property source to the application context, populated from
* a pre-existing ZooKeeper node.
*/
@Override
public void initialize(ConfigurableApplicationContext applicationContext) {
logger.trace("Attempting to add ZooKeeper-derived properties to ApplicationContext PropertySources");
try {
populateProjectProperties();
Properties properties = populatePropertiesFromZooKeeper();
PropertiesPropertySource propertySource = new PropertiesPropertySource("zookeeper", properties);
applicationContext.getEnvironment().getPropertySources().addFirst(propertySource);
logger.debug("Added ZooKeeper-derived properties to ApplicationContext PropertySources");
curator.close();
} catch (IOException e) {
logger.error("IO error attempting to load properties from ZooKeeper", e);
throw new IllegalStateException("Could not load ZooKeeper configuration");
} catch (Exception e) {
logger.error("IO error attempting to load properties from ZooKeeper", e);
throw new IllegalStateException("Could not load ZooKeeper configuration");
} finally {
if (curator != null && curator.isStarted()) {
curator.close();
}
}
}
/**
* Populate the Maven artifact name and version from a property file that
* should be on the classpath, with values entered via Maven filtering.
*
* There is a way of doing these with manifests, but it's a right faff when
* creating shaded uber-jars.
*
* @throws IOException
*/
private void populateProjectProperties() throws IOException {
logger.trace("Attempting to get project name and version from properties file");
try {
ResourcePropertySource projectProps = new ResourcePropertySource("project.properties");
this.projectName = (String) projectProps.getProperty("project.name");
this.projectVersion = (String) projectProps.getProperty("project.version");
} catch (IOException e) {
logger.error("IO error trying to find project name and version, in order to get properties from ZooKeeper");
}
}
/**
* Do the actual loading of properties.
*
* @return
* @throws Exception
* @throws IOException
*/
private Properties populatePropertiesFromZooKeeper() throws Exception, IOException {
logger.debug("Attempting to get properties from ZooKeeper");
try {
byte[] bytes = curator.getData().forPath("/distributed-config/" + projectName + "/" + projectVersion);
InputStream in = new ByteArrayInputStream(bytes);
Properties properties = new Properties();
properties.load(in);
return properties;
} catch (NoNodeException e) {
logger.error("Could not load application configuration from ZooKeeper as no node existed for project [{}]:[{}]", projectName, projectVersion);
throw e;
}
}
}
ResourcePropertySource和context.xml示例，还是使用ConfigurableApplicationContext？由于缺少属性，我无法启动上下文。先感谢您！ - Anton Kirillov