springboot @ConfigurationProperties 列表重新加载不起作用

Question

I have a problem that i config with @ConfigurationProperties when this config changed, the config-object not change. The config is list. if add config the list change, but if remove config the list not change.

@ConfigurationProperties(prefix = "zzzz.kafka")

public class ToadDynamicProps {

    private List<String> bootstrapServers;

    public ToadDynamicProps() {
        System.out.println(bootstrapServers + " ===============");
    }

    public List<String> getBootstrapServers() {
        return bootstrapServers;
    }

    public void setBootstrapServers(List<String> bootstrapServers) {
        this.bootstrapServers = bootstrapServers;
    }
}

And I implement listener by myself like that:

    @Override
    public void onConfigChange(Map<String, String> properties) {

        if (log.isDebugEnabled()) {
            log.debug("ToadContextRefresher invoked, changed keys: {}", properties.keySet());
        }

        // update environment
        MutablePropertySources targetSources = context.getEnvironment().getPropertySources();
        CompositePropertySource compositeSource = (CompositePropertySource) targetSources.get(BOOTSTRAP_PROPERTY_SOURCE_NAME);
        CompositePropertySource newBootstrapSource = new CompositePropertySource(BOOTSTRAP_PROPERTY_SOURCE_NAME);
        //TODO fix
        if(null == compositeSource) {
            return ;
        }

        // shallow copy for non-toad propertySource, swap toad propertySource
        for (PropertySource part : compositeSource.getPropertySources()) {
            if (Objects.equals(part.getName(), TOAD_PROPERTY_KEY)) {
                log.debug("Found toad property source in environment, update it...");
                Map<String, Object> oldProperties = ((MapPropertySource) part).getSource();
                Map<String, Object> newProperties = new HashMap<>(oldProperties);
                newProperties.putAll(properties);
                MapPropertySource newToadSource = new MapPropertySource(TOAD_PROPERTY_KEY, newProperties);
                newBootstrapSource.addPropertySource(newToadSource);
            }
            newBootstrapSource.addPropertySource(part);
        }
        targetSources.replace(BOOTSTRAP_PROPERTY_SOURCE_NAME, newBootstrapSource);

        Set<String> changedKeys = properties.keySet();
        this.context.publishEvent(new EnvironmentChangeEvent(context, changedKeys));
       
        this.scope.refreshAll();
    }

Answer 1

Make sure that the class (ToadDynamicProps) should have annotated with @Configuration or you need to provide @EnableConfigurationProperties(ToadDynamicProps.class) in the main Spring application class to bind the properties into the POJO.

Make sure the property from property file and the class (with given prefix) has proper binding.

Make sure the class file and property file are compiled properly when you change it.

Make your class implementing serializable (if needed).

Let me know if you still face an issue after verifying this.