使用前缀读取限定的yaml文件，而不使用注释或xml

Question

我的用例有点奇怪，但基本上，我想读取一个yaml文件的一部分并将其映射到spring应用程序中的相应java对象。这是一个非常常见且简单的操作（只使用@ConfigurationProperties）。

但是，就我而言，我想在生命周期的早期，即BeanFactoryPostProcessor挂钩时完成此读取 - 以便使用yml中指定的指令动态创建多个bean。

我可以使用application.properties而不是application.yml

我希望使用yml来将yml的一部分映射到POJO，并使用分层映射文件和数据结构（列表，映射等）。

这是一个如何阅读application.properties的示例。 https://blog.pchudzik.com/201705/dynamic-beans/

我在https://github.com/balamuru/yaml-loader设置了一个简单的骨架项目来尝试不同的技术。有任何想法吗 ？

@Component
@EnableConfigurationProperties(SampleDataConfig.class)
class ConfigurableBeanFactory implements BeanFactoryPostProcessor, InitializingBean {
    private List<String> beanInstances = new ArrayList<>();

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        final BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;

        Map<String, SampleDataConfig> beans = beanFactory.getBeansOfType(SampleDataConfig.class);
        System.err.println("");

        beanInstances.forEach(instance -> {
            registry.registerBeanDefinition(instance, BeanDefinitionBuilder
                    .rootBeanDefinition(SampleDataConfig.class)
                    .addConstructorArgValue(instance)
                    .getBeanDefinition());
        });
    }

    @Override
    public void afterPropertiesSet() throws Exception {
//        this.beanInstances = asList(PropertiesLoaderUtils
//                .loadProperties(new ClassPathResource("/application.properties"))
//                .getProperty("dynamic-beans.instances", "")
//                .split(","));

        /**
         * Rather than reading from application.properties,
         * I would like to be able to load up the relevant prefix qualified segments (com.foo.bar.stuff) mapping to my POJO (SampleDataConfig,class)
         * loaded from application.yml
         */
    }

}

在内部，spring使用以下机制，但我希望有一种更简单的方法来利用它而无需重新发明spring :)

public class ConfigurationPropertiesBindingPostProcessor ...{
.
.

    private void postProcessBeforeInitialization(Object bean, String beanName,
            ConfigurationProperties annotation) {
        Object target = bean;
        PropertiesConfigurationFactory<Object> factory = new PropertiesConfigurationFactory<Object>(
                target);
        factory.setPropertySources(this.propertySources);
        factory.setValidator(determineValidator(bean));
        // If no explicit conversion service is provided we add one so that (at least)
        // comma-separated arrays of convertibles can be bound automatically
        factory.setConversionService(this.conversionService == null
                ? getDefaultConversionService() : this.conversionService);
        if (annotation != null) {
            factory.setIgnoreInvalidFields(annotation.ignoreInvalidFields());
            factory.setIgnoreUnknownFields(annotation.ignoreUnknownFields());
            factory.setExceptionIfInvalid(annotation.exceptionIfInvalid());
            factory.setIgnoreNestedProperties(annotation.ignoreNestedProperties());
            if (StringUtils.hasLength(annotation.prefix())) {
                factory.setTargetName(annotation.prefix()); //====> use annotation prefix
            }
        }
        try {
            factory.bindPropertiesToTarget(); //===> bind properties
        }

谢谢

Answer 1

YamlPropertiesFactoryBean yaml = new YamlPropertiesFactoryBean();
yaml.setResources(new ClassPathResource("application.yml"));
configProperty = yaml.getObject();
Set<Object> keys = configProperty.keySet();

下面是我的YAML配置，如下所示：

template:
  config:
    broker-urls:
    - tcp://127.0.0.1:61616
    - tcp://127.0.0.1:61617
    - tcp://127.0.0.1:61618
    qeues:
    - Test
    - Demo
    - Qeue3

应用上面的代码后，您将获得如下所示的转换属性：

template.config.broker-urls[0]=tcp://127.0.0.1:61616
template.config.broker-urls[1]=tcp://127.0.0.1:61617
template.config.broker-urls[1]=tcp://127.0.0.1:61618

template.config.qeues[0]=Test
template.config.qeues[1]=Demo
template.config.qeues[1]=Qeue3