如何重新加载 apache commons configurations2 属性

Question

任何人都可以指导我如何重新加载 apache 公共配置 2 属性。我无法在任何地方找到这个的任何实现。 apache 文档有点太抽象了。这是我目前所拥有的，但它没有用。

    CombinedConfiguration cc = new CombinedConfiguration();

    Parameters params = new Parameters();
    File configFile = new File("config.properties");
    File emsFile = new File("anotherconfig.properties");

    ReloadingFileBasedConfigurationBuilder<FileBasedConfiguration> configBuilder =
        new ReloadingFileBasedConfigurationBuilder<FileBasedConfiguration>(PropertiesConfiguration.class)
        .configure(params.fileBased()
            .setFile(configFile));
    PeriodicReloadingTrigger reloadTrg = new PeriodicReloadingTrigger(configBuilder.getReloadingController(), null, 5, TimeUnit.SECONDS);
    reloadTrg.start();

    cc.addConfiguration(configBuilder.getConfiguration());

    FileBasedConfigurationBuilder<FileBasedConfiguration> emsBuilder =
            new FileBasedConfigurationBuilder<FileBasedConfiguration>(PropertiesConfiguration.class)
            .configure(params.properties()
                .setFile(emsFile));
    cc.addConfiguration(emsBuilder.getConfiguration());

    DataSource ds = EmsDataSource.getInstance().getDatasource(this);

     BasicConfigurationBuilder<DatabaseConfiguration> dbBuilder =
         new BasicConfigurationBuilder<DatabaseConfiguration>(DatabaseConfiguration.class);
     dbBuilder.configure(
         params.database()
             .setDataSource(ds)
             .setTable("EMS_CONFIG")
             .setKeyColumn("KEY")
             .setValueColumn("VALUE")
     );
    cc.addConfiguration(dbBuilder.getConfiguration());

Answer 1

从构建器获取的配置不会自动更新。每次读取都需要从构建器中获取配置。

来自Automatic Reloading of Configuration Sources：

One important point to keep in mind when using this approach to reloading is that reloads are only functional if the builder is used as central component for accessing configuration data. The configuration instance obtained from the builder will not change automagically! So if an application fetches a configuration object from the builder at startup and then uses it throughout its life time, changes on the external configuration file become never visible. The correct approach is to keep a reference to the builder centrally and obtain the configuration from there every time configuration data is needed.

Answer 2

使用以下代码：

@Component
public class ApplicationProperties {
    private PropertiesConfiguration configuration;

    @PostConstruct
    private void init() {
        try {
            String filePath = PropertiesConstants.PROPERTIES_FILE_PATH;
            System.out.println("Loading the properties file: " + filePath);
            configuration = new PropertiesConfiguration(filePath);

            //Create new FileChangedReloadingStrategy to reload the properties file based on the given time interval
            FileChangedReloadingStrategy fileChangedReloadingStrategy = new FileChangedReloadingStrategy();
           fileChangedReloadingStrategy.setRefreshDelay(PropertiesConstants.REFRESH_DELAY);
            configuration.setReloadingStrategy(fileChangedReloadingStrategy);
        } catch (ConfigurationException e) {
            e.printStackTrace();
        }
    }

    public String getProperty(String key) {
        return (String) configuration.getProperty(key);
    }

    public void setProperty(String key, Object value) {
        configuration.setProperty(key, value);
    }

    public void save() {
        try {
            configuration.save();
        } catch (ConfigurationException e) {
            e.printStackTrace();
        }
    }
}