# SpringBoot ConfigurationProperties
- Author: [HuiFer](https://github.com/huifer)
- 源码阅读仓库: [SourceHot-spring-boot](https://github.com/SourceHot/spring-boot-read)
- 本文主要对`org.springframework.boot.context.properties.ConfigurationProperties`进行分析
## ConfigurationProperties
- 顶部注释
```java
* @see ConfigurationPropertiesScan
* @see ConstructorBinding
* @see ConfigurationPropertiesBindingPostProcessor
* @see EnableConfigurationProperties
```
看到`ConfigurationPropertiesScan` 去看看这个
## ConfigurationPropertiesScan
```java
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import(ConfigurationPropertiesScanRegistrar.class)
@EnableConfigurationProperties
public @interface ConfigurationPropertiesScan {}
```
- 熟悉的**Import**注解
## ConfigurationPropertiesScanRegistrar
- debug 没有抓到后续补充
## EnableConfigurationProperties
```java
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import(EnableConfigurationPropertiesRegistrar.class)
public @interface EnableConfigurationProperties {
}
```
## EnableConfigurationPropertiesRegistrar
- 该类会读取**spring.factories**
- 中`org.springframework.boot.autoconfigure.EnableAutoConfiguration=\` 这样的
```
org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration$DispatcherServletConfiguration
org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration$DispatcherServletRegistrationConfiguration
org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$Jackson2ObjectMapperBuilderCustomizerConfiguration
org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration$StringHttpMessageConverterConfiguration
org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration
org.springframework.boot.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration
org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration
org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration
org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration
```
```java
@Override
public void registerBeanDefinitions(AnnotationMetadata metadata, BeanDefinitionRegistry registry) {
// 注册bean
registerInfrastructureBeans(registry);
// 配置属性Bean注册器
ConfigurationPropertiesBeanRegistrar beanRegistrar = new ConfigurationPropertiesBeanRegistrar(registry);
// 循环注册
getTypes(metadata).forEach(beanRegistrar::register);
}
```
### registerInfrastructureBeans
```java
static void registerInfrastructureBeans(BeanDefinitionRegistry registry) {
// 属性绑定后置处理器
ConfigurationPropertiesBindingPostProcessor.register(registry);
// 属性校验器
ConfigurationPropertiesBeanDefinitionValidator.register(registry);
ConfigurationBeanFactoryMetadata.register(registry);
}
```
- 此处操作逻辑基本相同,是否存在这个 beanName 存在直接注册，不存在补充
#### ConfigurationPropertiesBindingPostProcessor.register(registry)
```java
public static void register(BeanDefinitionRegistry registry) {
Assert.notNull(registry, "Registry must not be null");
// 是否存在
if (!registry.containsBeanDefinition(BEAN_NAME)) {
GenericBeanDefinition definition = new GenericBeanDefinition();
definition.setBeanClass(ConfigurationPropertiesBindingPostProcessor.class);
definition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
registry.registerBeanDefinition(BEAN_NAME, definition);
}
ConfigurationPropertiesBinder.register(registry);
}
```
#### ConfigurationPropertiesBeanDefinitionValidator.register(registry)
```java
static void register(BeanDefinitionRegistry registry) {
Assert.notNull(registry, "Registry must not be null");
if (!registry.containsBeanDefinition(BEAN_NAME)) {
GenericBeanDefinition definition = new GenericBeanDefinition();
definition.setBeanClass(ConfigurationPropertiesBeanDefinitionValidator.class);
definition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
registry.registerBeanDefinition(BEAN_NAME, definition);
}
ConfigurationPropertiesBinder.register(registry);
}
```
### getTypes(metadata).forEach(beanRegistrar::register)
- 先看输入参数 **metadata**
- getTypes 结果
- 源码开始，先找出刚才的对象`org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration`
```java
@Configuration(proxyBeanMethods = false)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
@ConditionalOnClass(ServletRequest.class)
@ConditionalOnWebApplication(type = Type.SERVLET)
@EnableConfigurationProperties(ServerProperties.class)
@Import({ ServletWebServerFactoryAutoConfiguration.BeanPostProcessorsRegistrar.class,
ServletWebServerFactoryConfiguration.EmbeddedTomcat.class,
ServletWebServerFactoryConfiguration.EmbeddedJetty.class,
ServletWebServerFactoryConfiguration.EmbeddedUndertow.class })
public class ServletWebServerFactoryAutoConfiguration {}
```
```java
/**
* 找出 {@link EnableConfigurationProperties} 注解标记的中的属性值,并且返回值不是void
* @param metadata
* @return
*/
private Set<Class<?>> getTypes(AnnotationMetadata metadata) {
return
metadata.getAnnotations().stream(EnableConfigurationProperties.class)
.flatMap((annotation) -> Arrays.stream(annotation.getClassArray(MergedAnnotation.VALUE)))
.filter((type) -> void.class != type).collect(Collectors.toSet());
}
```
- 这里我们可以直接知道返回的是`@EnableConfigurationProperties(ServerProperties.class)` 的数据值: `ServerProperties.class`
循环注册
```java
void register(Class<?> type) {
MergedAnnotation<ConfigurationProperties> annotation = MergedAnnotations
.from(type, SearchStrategy.TYPE_HIERARCHY).get(ConfigurationProperties.class);
register(type, annotation);
}
```
---
## ConfigurationPropertiesBindingPostProcessor
### postProcessBeforeInitialization
```java
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
// 绑定
bind(ConfigurationPropertiesBean.get(this.applicationContext, bean, beanName));
return bean;
}
```
- get
```java
public static ConfigurationPropertiesBean get(ApplicationContext applicationContext, Object bean, String beanName) {
// 寻找工厂方法
Method factoryMethod = findFactoryMethod(applicationContext, beanName);
// 创建 ConfigurationPropertiesBean
return create(beanName, bean, bean.getClass(), factoryMethod);
}
```
```java
private static Method findFactoryMethod(ConfigurableListableBeanFactory beanFactory, String beanName) {
// 判断是否存在这个beanName
if (beanFactory.containsBeanDefinition(beanName)) {
// 获取bean定义
BeanDefinition beanDefinition = beanFactory.getMergedBeanDefinition(beanName);
// 类型判断
if (beanDefinition instanceof RootBeanDefinition) {
// 解析方法
Method resolvedFactoryMethod = ((RootBeanDefinition) beanDefinition).getResolvedFactoryMethod();
if (resolvedFactoryMethod != null) {
return resolvedFactoryMethod;
}
}
return findFactoryMethodUsingReflection(beanFactory, beanDefinition);
}
return null;
}
```
```java
private static Method findFactoryMethodUsingReflection(ConfigurableListableBeanFactory beanFactory,
BeanDefinition beanDefinition) {
// 工厂方法
String factoryMethodName = beanDefinition.getFactoryMethodName();
// 工厂bean
String factoryBeanName = beanDefinition.getFactoryBeanName();
if (factoryMethodName == null || factoryBeanName == null) {
return null;
}
// 转换对象
Class<?> factoryType = beanFactory.getType(factoryBeanName);
if (factoryType.getName().contains(ClassUtils.CGLIB_CLASS_SEPARATOR)) {
factoryType = factoryType.getSuperclass();
}
AtomicReference<Method> factoryMethod = new AtomicReference<>();
ReflectionUtils.doWithMethods(factoryType, (method) -> {
// 判断是否是需要的方法
if (method.getName().equals(factoryMethodName)) {
// 设置方法
factoryMethod.set(method);
}
});
// 返回方法
return factoryMethod.get();
}
```
### create
- `org.springframework.boot.context.properties.ConfigurationPropertiesBean#create`
```java
private static ConfigurationPropertiesBean create(String name, Object instance, Class<?> type, Method factory) {
// 找注解
ConfigurationProperties annotation = findAnnotation(instance, type, factory, ConfigurationProperties.class);
if (annotation == null) {
return null;
}
// 找注解
Validated validated = findAnnotation(instance, type, factory, Validated.class);
// 注解列表
Annotation[] annotations = (validated != null) ? new Annotation[] { annotation, validated }
: new Annotation[] { annotation };
// 类型解析
ResolvableType bindType = (factory != null) ? ResolvableType.forMethodReturnType(factory)
: ResolvableType.forClass(type);
// 绑定结果对象
Bindable<Object> bindTarget = Bindable.of(bindType).withAnnotations(annotations);
if (instance != null) {
bindTarget = bindTarget.withExistingValue(instance);
}
return new ConfigurationPropertiesBean(name, instance, annotation, bindTarget);
}
```
- 第一个需要做的类: `org.springframework.boot.autoconfigure.web.ServerProperties`
- `annotation`
- `bindType`
- 返回对象
- 此时数据还没有进去
#### bind
- 数据绑定
直接看结果
- 上述配置和我在配置文件中写的配置一致
```yml
server:
port: 9999
```
- 具体方法: `org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor#bind`
```java
private void bind(ConfigurationPropertiesBean bean) {
if (bean == null || hasBoundValueObject(bean.getName())) {
return;
}
Assert.state(bean.getBindMethod() == BindMethod.JAVA_BEAN, "Cannot bind @ConfigurationProperties for bean '"
+ bean.getName() + "'. Ensure that @ConstructorBinding has not been applied to regular bean");
try {
// 最终的绑定
this.binder.bind(bean);
}
catch (Exception ex) {
throw new ConfigurationPropertiesBindException(bean, ex);
}
}
```
```java
BindResult<?> bind(ConfigurationPropertiesBean propertiesBean) {
// 最后的结果
Bindable<?> target = propertiesBean.asBindTarget();
// 注解获取
ConfigurationProperties annotation = propertiesBean.getAnnotation();
// 获取处理器
BindHandler bindHandler = getBindHandler(target, annotation);
//
return getBinder().bind(annotation.prefix(), target, bindHandler);
}
```
##### findProperty
```java
private ConfigurationProperty findProperty(ConfigurationPropertyName name, Context context) {
if (name.isEmpty()) {
return null;
}
for (ConfigurationPropertySource source : context.getSources()) {
// 获取具体的一个属性值
ConfigurationProperty property = source.getConfigurationProperty(name);
if (property != null) {
return property;
}
}
return null;
}
```
- `org.springframework.boot.context.properties.source.SpringConfigurationPropertySource#getConfigurationProperty`
```java
@Override
public ConfigurationProperty getConfigurationProperty(ConfigurationPropertyName name) {
PropertyMapping[] mappings = getMapper().map(name);
return find(mappings, name);
}
```
```java
protected final ConfigurationProperty find(PropertyMapping[] mappings, ConfigurationPropertyName name) {
for (PropertyMapping candidate : mappings) {
if (candidate.isApplicable(name)) {
ConfigurationProperty result = find(candidate);
if (result != null) {
return result;
}
}
}
return null;
}
```
```java
private ConfigurationProperty find(PropertyMapping mapping) {
// 需要读取的配置信息的key
String propertySourceName = mapping.getPropertySourceName();
// 信息的value
Object value = getPropertySource().getProperty(propertySourceName);
if (value == null) {
return null;
}
// 创建对象
ConfigurationPropertyName configurationPropertyName = mapping.getConfigurationPropertyName();
Origin origin = PropertySourceOrigin.get(this.propertySource, propertySourceName);
// 包装返回
return ConfigurationProperty.of(configurationPropertyName, value, origin);
}
```
##### getBindHandler
```java
private <T> BindHandler getBindHandler(Bindable<T> target, ConfigurationProperties annotation) {
// 获取校验接口列表
List<Validator> validators = getValidators(target);
// 处理器
BindHandler handler = new IgnoreTopLevelConverterNotFoundBindHandler();
if (annotation.ignoreInvalidFields()) {
// 忽略错误的绑定处理器
handler = new IgnoreErrorsBindHandler(handler);
}
if (!annotation.ignoreUnknownFields()) {
UnboundElementsSourceFilter filter = new UnboundElementsSourceFilter();
// 未绑定元素处理器
handler = new NoUnboundElementsBindHandler(handler, filter);
}
if (!validators.isEmpty()) {
// 校验绑定处理器
handler = new ValidationBindHandler(handler, validators.toArray(new Validator[0]));
}
for (ConfigurationPropertiesBindHandlerAdvisor advisor : getBindHandlerAdvisors()) {
// handler
handler = advisor.apply(handler);
}
return handler;
}
```
- 最终获取得到的处理器
- 最后的 bind
```java
private <T> Object bindObject(ConfigurationPropertyName name, Bindable<T> target, BindHandler handler,
Context context, boolean allowRecursiveBinding) {
// 获取属性
ConfigurationProperty property = findProperty(name, context);
if (property == null && containsNoDescendantOf(context.getSources(), name) && context.depth != 0) {
return null;
}
AggregateBinder<?> aggregateBinder = getAggregateBinder(target, context);
if (aggregateBinder != null) {
return bindAggregate(name, target, handler, context, aggregateBinder);
}
if (property != null) {
try {
return bindProperty(target, context, property);
}
catch (ConverterNotFoundException ex) {
// We might still be able to bind it using the recursive binders
Object instance = bindDataObject(name, target, handler, context, allowRecursiveBinding);
if (instance != null) {
return instance;
}
throw ex;
}
}
return bindDataObject(name, target, handler, context, allowRecursiveBinding);
}
```
配置信息到此绑定成功,关于如何处理集合相关的配置请各位读者自行学习
---