import lombok.AllArgsConstructor;
import org.springframework.beans.factory.config.YamlPropertiesFactoryBean;
import org.springframework.core.env.PropertiesPropertySource;
import org.springframework.core.env.PropertySource;
import org.springframework.core.io.support.EncodedResource;
import org.springframework.core.io.support.PropertySourceFactory;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Properties;

/**
 * @description:
 * @author: jianjun.ren
 * @date: Created in 2020/9/24 12:05
 */
@AllArgsConstructor
public class YamlPropertySourceFactory implements PropertySourceFactory {
	//這個(gè)方法有2個(gè)入?yún)?，分別為資源名稱和資源對(duì)象，這是第一步
    public PropertySource< ? > createPropertySource(String name, EncodedResource resource) throws IOException {
    
    	//這是第二步，根據(jù)流對(duì)象產(chǎn)出Properties對(duì)象
        Properties propertiesFromYaml = loadYamlIntoProperties(resource);
        String sourceName = name != null ? name : resource.getResource().getFilename();
        assert sourceName != null;
        
        //這是第三部，根據(jù)Properties對(duì)象，產(chǎn)出PropertySource對(duì)象，放入到Spring中
        return new PropertiesPropertySource(sourceName, propertiesFromYaml);
    }

    private Properties loadYamlIntoProperties(EncodedResource resource) throws FileNotFoundException {
        try {
            YamlPropertiesFactoryBean factory = new YamlPropertiesFactoryBean();
            factory.setResources(resource.getResource());
            factory.afterPropertiesSet();
            return factory.getObject();
        } catch (IllegalStateException e) {
            Throwable cause = e.getCause();
            if (cause instanceof FileNotFoundException) {
                throw (FileNotFoundException) e.getCause();
            }
            throw e;
        }
    }
}