myconfig.name=test
myconfig.age=22
myconfig.desc=這是我的測試描述

@Component
@ConfigurationProperties(prefix = "myconfig")
public class MyConfig {
private String name;
private Integer age;
private String desc;
  //get/set 略
  @Override
public String toString() {
	return "MyConfig [name=" + name + ", age=" + age + ", desc=" + desc + "]";
}
}

public static void main(String[] args) throws Exception {
	SpringApplication springApplication = new SpringApplication(Application.class);
	// 非web環(huán)境
	springApplication.setWebEnvironment(false);
	ConfigurableApplicationContext application = springApplication.run(args);

	MyConfig config = application.getBean(MyConfig.class);
	log.info(config.toString());
	application.close();
}

com.cml.chat.lesson.lesson3.Application - MyConfig [name=test, age=22, desc=這是我的測試描述]

public class ConfigurationPropertiesBindingPostProcessor implements BeanPostProcessor,
	BeanFactoryAware, EnvironmentAware, ApplicationContextAware, InitializingBean,
	DisposableBean, ApplicationListener<ContextRefreshedEvent>, PriorityOrdered 

@Override
public Object postProcessBeforeInitialization(Object bean, String beanName)
		throws BeansException {
	//直接通過查找添加了ConfigurationProperties注解的的類
	ConfigurationProperties annotation = AnnotationUtils
			.findAnnotation(bean.getClass(), ConfigurationProperties.class);
	if (annotation != null) {
		postProcessBeforeInitialization(bean, beanName, annotation);
	}
	//查找使用工廠bean中是否有ConfigurationProperties注解
	annotation = this.beans.findFactoryAnnotation(beanName,
			ConfigurationProperties.class);
	if (annotation != null) {
		postProcessBeforeInitialization(bean, beanName, annotation);
	}
	return bean;
}

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());
		}
	}
	try {
		factory.bindPropertiesToTarget();
	}
	catch (Exception ex) {
		String targetClass = ClassUtils.getShortName(target.getClass());
		throw new BeanCreationException(beanName, "Could not bind properties to "
				+ targetClass + " (" + getAnnotationDetails(annotation) + ")", ex);
	}
}

public class ConfigurationBeanFactoryMetaData implements BeanFactoryPostProcessor {

private ConfigurableListableBeanFactory beanFactory;

private Map<String, MetaData> beans = new HashMap<String, MetaData>();

@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)
		throws BeansException {
	this.beanFactory = beanFactory;
 //迭代所有的bean定義，找出那些是工廠bean的對象添加到beans中
	for (String name : beanFactory.getBeanDefinitionNames()) {
		BeanDefinition definition = beanFactory.getBeanDefinition(name);
		String method = definition.getFactoryMethodName();
		String bean = definition.getFactoryBeanName();
		if (method != null && bean != null) {
			this.beans.put(name, new MetaData(bean, method));
		}
	}
}

public <A extends Annotation> Map<String, Object> getBeansWithFactoryAnnotation(
		Class<A> type) {
	Map<String, Object> result = new HashMap<String, Object>();
	for (String name : this.beans.keySet()) {
		if (findFactoryAnnotation(name, type) != null) {
			result.put(name, this.beanFactory.getBean(name));
		}
	}
	return result;
}

public <A extends Annotation> A findFactoryAnnotation(String beanName,
		Class<A> type) {
	Method method = findFactoryMethod(beanName);
	return (method == null ? null : AnnotationUtils.findAnnotation(method, type));
}

//略...
	
private static class MetaData {
	private String bean;
	private String method;
  //構造方法和其他方法略...
}

}

private void postProcessBeforeInitialization(Object bean, String beanName,
		ConfigurationProperties annotation) {
	Object target = bean;
	PropertiesConfigurationFactory<Object> factory = new PropertiesConfigurationFactory<Object>(
			target);
	//重點，這里設置數據來源
	factory.setPropertySources(this.propertySources);
	factory.setValidator(determineValidator(bean));
	//設置轉換器
	factory.setConversionService(this.conversionService == null
			? getDefaultConversionService() : this.conversionService);
	if (annotation != null) {
	//將annotation中配置的屬性配置到factory中
	}
	try {
	  //這里是核心，綁定屬性值到對象中
		factory.bindPropertiesToTarget();
	}
	catch (Exception ex) {
	//拋出異常
	}
}

private void doBindPropertiesToTarget() throws BindException {
	RelaxedDataBinder dataBinder 
  //略...
  //1、獲取bean中所有的屬性名稱
  Set<String> names = getNames(relaxedTargetNames);
  //2、將屬性名稱和前綴轉換為配置文件的key值
  PropertyValues propertyValues = getPropertySourcesPropertyValues(names,relaxedTargetNames);
  //3、通過上面兩個步驟找到的屬性從配置文件中獲取數據通過反射注入到bean中
	dataBinder.bind(propertyValues);
	//數據校驗
	if (this.validator != null) {
		dataBinder.validate();
	}
	//判斷數據綁定過程中是否有錯誤
	checkForBindingErrors(dataBinder);
}

public void bind(PropertyValues pvs) {
	MutablePropertyValues mpvs = (pvs instanceof MutablePropertyValues) ?
			(MutablePropertyValues) pvs : new MutablePropertyValues(pvs);
	doBind(mpvs);
}
protected void doBind(MutablePropertyValues mpvs) {
	checkAllowedFields(mpvs);
	checkRequiredFields(mpvs);
	//進行賦值
	applyPropertyValues(mpvs);
}
protected void applyPropertyValues(MutablePropertyValues mpvs) {
	try {
		// Bind request parameters onto target object.
		getPropertyAccessor().setPropertyValues(mpvs, isIgnoreUnknownFields(), isIgnoreInvalidFields());
	}
	catch (PropertyBatchUpdateException ex) {
		// Use bind error processor to create FieldErrors.
		for (PropertyAccessException pae : ex.getPropertyAccessExceptions()) {
			getBindingErrorProcessor().processPropertyAccessException(pae, getInternalBindingResult());
		}
	}
}