|
|
|
|
# SpringBoot ConditionalOnBean
|
|
|
|
|
|
|
|
|
|
- Author: [HuiFer](https://github.com/huifer)
|
|
|
|
|
- 源码阅读仓库: [SourceHot-spring-boot](https://github.com/SourceHot/spring-boot-read)
|
|
|
|
|
|
|
|
|
|
- 在 SpringBoot 中有下列当 XXX 存在或不存的时候执行初始化
|
|
|
|
|
- ConditionalOnBean
|
|
|
|
|
ConditionalOnClass
|
|
|
|
|
ConditionalOnCloudPlatform
|
|
|
|
|
ConditionalOnExpression
|
|
|
|
|
ConditionalOnJava
|
|
|
|
|
ConditionalOnJndi
|
|
|
|
|
ConditionalOnMissingBean
|
|
|
|
|
ConditionalOnMissingClass
|
|
|
|
|
ConditionalOnNotWebApplication
|
|
|
|
|
ConditionalOnProperty
|
|
|
|
|
ConditionalOnResource
|
|
|
|
|
ConditionalOnSingleCandidate
|
|
|
|
|
ConditionalOnWebApplication
|
|
|
|
|
|
|
|
|
|
## ConditionalOnBean
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
@Target({ ElementType.TYPE, ElementType.METHOD })
|
|
|
|
|
@Retention(RetentionPolicy.RUNTIME)
|
|
|
|
|
@Documented
|
|
|
|
|
@Conditional(OnBeanCondition.class)
|
|
|
|
|
public @interface ConditionalOnBean {
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* 需要匹配的 bean 类型
|
|
|
|
|
*/
|
|
|
|
|
Class<?>[] value() default {};
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* 需要匹配的 bean 类型
|
|
|
|
|
*/
|
|
|
|
|
String[] type() default {};
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* 匹配的 bean 注解
|
|
|
|
|
*/
|
|
|
|
|
Class<? extends Annotation>[] annotation() default {};
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* 需要匹配的 beanName
|
|
|
|
|
*/
|
|
|
|
|
String[] name() default {};
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* 搜索策略
|
|
|
|
|
*/
|
|
|
|
|
SearchStrategy search() default SearchStrategy.ALL;
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
*/
|
|
|
|
|
Class<?>[] parameterizedContainer() default {};
|
|
|
|
|
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## SearchStrategy
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
public enum SearchStrategy {
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* 当前 上下文
|
|
|
|
|
*/
|
|
|
|
|
CURRENT,
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* 找所有的父容器
|
|
|
|
|
*/
|
|
|
|
|
ANCESTORS,
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* 当前上下文+父容器
|
|
|
|
|
*/
|
|
|
|
|
ALL
|
|
|
|
|
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## OnBeanCondition
|
|
|
|
|
|
|
|
|
|
- org.springframework.boot.autoconfigure.condition.OnBeanCondition
|
|
|
|
|
|
|
|
|
|
- 这个类是一个条件类,相关的还有
|
|
|
|
|
|
|
|
|
|
```properties
|
|
|
|
|
org.springframework.boot.autoconfigure.AutoConfigurationImportFilter=\
|
|
|
|
|
org.springframework.boot.autoconfigure.condition.OnBeanCondition,\
|
|
|
|
|
org.springframework.boot.autoconfigure.condition.OnClassCondition,\
|
|
|
|
|
org.springframework.boot.autoconfigure.condition.OnWebApplicationCondition
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
- 类图
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
在看这部分源码之前需要先了解 `Conditional`和`Condition`的源码
|
|
|
|
|
|
|
|
|
|
- 简单描述
|
|
|
|
|
|
|
|
|
|
通过实现`Condition` 来确认是否初始化 bean
|
|
|
|
|
|
|
|
|
|
- 从类图上我们可以看到 `condition` 的继承关系. 在这里需要去找到`SpringBootCondition`
|
|
|
|
|
|
|
|
|
|
- `org.springframework.boot.autoconfigure.condition.SpringBootCondition#matches(org.springframework.context.annotation.ConditionContext, org.springframework.core.type.AnnotatedTypeMetadata)`
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
@Override
|
|
|
|
|
public final boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
|
|
|
|
|
// 类名或者方法名标记
|
|
|
|
|
String classOrMethodName = getClassOrMethodName(metadata);
|
|
|
|
|
try {
|
|
|
|
|
// 比较类,子类实现
|
|
|
|
|
ConditionOutcome outcome = getMatchOutcome(context, metadata);
|
|
|
|
|
// 日志输出
|
|
|
|
|
logOutcome(classOrMethodName, outcome);
|
|
|
|
|
// 报告记录
|
|
|
|
|
recordEvaluation(context, classOrMethodName, outcome);
|
|
|
|
|
// 返回匹配结果
|
|
|
|
|
return outcome.isMatch();
|
|
|
|
|
}
|
|
|
|
|
catch (NoClassDefFoundError ex) {
|
|
|
|
|
throw new IllegalStateException("Could not evaluate condition on " + classOrMethodName + " due to "
|
|
|
|
|
+ ex.getMessage() + " not found. Make sure your own configuration does not rely on "
|
|
|
|
|
+ "that class. This can also happen if you are "
|
|
|
|
|
+ "@ComponentScanning a springframework package (e.g. if you "
|
|
|
|
|
+ "put a @ComponentScan in the default package by mistake)", ex);
|
|
|
|
|
}
|
|
|
|
|
catch (RuntimeException ex) {
|
|
|
|
|
throw new IllegalStateException("Error processing condition on " + getName(metadata), ex);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
- `getOutcomes` 子类实现
|
|
|
|
|
|
|
|
|
|
`org.springframework.boot.autoconfigure.condition.OnBeanCondition#getOutcomes`
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
String[] autoConfigurationClasses,
|
|
|
|
|
AutoConfigurationMetadata autoConfigurationMetadata
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
- 第一个参数: 需要自动配置的类
|
|
|
|
|
- 配置注解信息
|
|
|
|
|
|
|
|
|
|
### ConditionOutcome 和 ConditionMessage
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
public class ConditionOutcome {
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* 是否匹配
|
|
|
|
|
*/
|
|
|
|
|
private final boolean match;
|
|
|
|
|
/**
|
|
|
|
|
* 条件信息
|
|
|
|
|
*/
|
|
|
|
|
private final ConditionMessage message;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
public final class ConditionMessage {
|
|
|
|
|
|
|
|
|
|
private String message;
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
- 造一个对象用来进行 debug
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
|
|
|
|
|
@Component
|
|
|
|
|
public class Beans {
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
@Bean
|
|
|
|
|
public A a() {
|
|
|
|
|
return new A();
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
@Bean
|
|
|
|
|
@ConditionalOnBean(value = A.class)
|
|
|
|
|
public B b() {
|
|
|
|
|
return new B();
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## getMatchOutcome
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
@Override
|
|
|
|
|
public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
|
|
|
|
|
// 条件信息
|
|
|
|
|
ConditionMessage matchMessage = ConditionMessage.empty();
|
|
|
|
|
// 获取注解求和
|
|
|
|
|
MergedAnnotations annotations = metadata.getAnnotations();
|
|
|
|
|
// 注解是否匹配
|
|
|
|
|
if (annotations.isPresent(ConditionalOnBean.class)) {
|
|
|
|
|
// 搜索 ConditionalOnBean 注解
|
|
|
|
|
Spec<ConditionalOnBean> spec = new Spec<>(context, metadata, annotations,
|
|
|
|
|
ConditionalOnBean.class);
|
|
|
|
|
// 匹配结果
|
|
|
|
|
MatchResult matchResult = getMatchingBeans(context, spec);
|
|
|
|
|
if (!matchResult.isAllMatched()) {
|
|
|
|
|
String reason = createOnBeanNoMatchReason(matchResult);
|
|
|
|
|
return ConditionOutcome.noMatch(spec.message().because(reason));
|
|
|
|
|
}
|
|
|
|
|
// 把注解解析出来获得文本
|
|
|
|
|
matchMessage = spec.message(matchMessage).found("bean", "beans").items(Style.QUOTE,
|
|
|
|
|
matchResult.getNamesOfAllMatches());
|
|
|
|
|
}
|
|
|
|
|
if (metadata.isAnnotated(ConditionalOnSingleCandidate.class.getName())) {
|
|
|
|
|
Spec<ConditionalOnSingleCandidate> spec = new SingleCandidateSpec(context, metadata, annotations);
|
|
|
|
|
MatchResult matchResult = getMatchingBeans(context, spec);
|
|
|
|
|
if (!matchResult.isAllMatched()) {
|
|
|
|
|
return ConditionOutcome.noMatch(spec.message().didNotFind("any beans").atAll());
|
|
|
|
|
}
|
|
|
|
|
else if (!hasSingleAutowireCandidate(context.getBeanFactory(), matchResult.getNamesOfAllMatches(),
|
|
|
|
|
spec.getStrategy() == SearchStrategy.ALL)) {
|
|
|
|
|
return ConditionOutcome.noMatch(spec.message().didNotFind("a primary bean from beans")
|
|
|
|
|
.items(Style.QUOTE, matchResult.getNamesOfAllMatches()));
|
|
|
|
|
}
|
|
|
|
|
matchMessage = spec.message(matchMessage).found("a primary bean from beans").items(Style.QUOTE,
|
|
|
|
|
matchResult.getNamesOfAllMatches());
|
|
|
|
|
}
|
|
|
|
|
if (metadata.isAnnotated(ConditionalOnMissingBean.class.getName())) {
|
|
|
|
|
Spec<ConditionalOnMissingBean> spec = new Spec<>(context, metadata, annotations,
|
|
|
|
|
ConditionalOnMissingBean.class);
|
|
|
|
|
MatchResult matchResult = getMatchingBeans(context, spec);
|
|
|
|
|
if (matchResult.isAnyMatched()) {
|
|
|
|
|
String reason = createOnMissingBeanNoMatchReason(matchResult);
|
|
|
|
|
return ConditionOutcome.noMatch(spec.message().because(reason));
|
|
|
|
|
}
|
|
|
|
|
matchMessage = spec.message(matchMessage).didNotFind("any beans").atAll();
|
|
|
|
|
}
|
|
|
|
|
return ConditionOutcome.match(matchMessage);
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
- 开始方法分析
|
|
|
|
|
|
|
|
|
|
### getMatchingBeans
|
|
|
|
|
|
|
|
|
|
- `org.springframework.boot.autoconfigure.condition.OnBeanCondition#getMatchingBeans`
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
protected final MatchResult getMatchingBeans(ConditionContext context, Spec<?> spec) {
|
|
|
|
|
// 获取上下文
|
|
|
|
|
ClassLoader classLoader = context.getClassLoader();
|
|
|
|
|
// 获取 IOC 容器
|
|
|
|
|
ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
|
|
|
|
|
// 扫描方式比较是否为当前上下文
|
|
|
|
|
boolean considerHierarchy = spec.getStrategy() != SearchStrategy.CURRENT;
|
|
|
|
|
|
|
|
|
|
Set<Class<?>> parameterizedContainers = spec.getParameterizedContainers();
|
|
|
|
|
if (spec.getStrategy() == SearchStrategy.ANCESTORS) {
|
|
|
|
|
BeanFactory parent = beanFactory.getParentBeanFactory();
|
|
|
|
|
Assert.isInstanceOf(ConfigurableListableBeanFactory.class, parent,
|
|
|
|
|
"Unable to use SearchStrategy.ANCESTORS");
|
|
|
|
|
beanFactory = (ConfigurableListableBeanFactory) parent;
|
|
|
|
|
}
|
|
|
|
|
// 结果对象初始化
|
|
|
|
|
MatchResult result = new MatchResult();
|
|
|
|
|
Set<String> beansIgnoredByType = getNamesOfBeansIgnoredByType(classLoader, beanFactory, considerHierarchy,
|
|
|
|
|
spec.getIgnoredTypes(), parameterizedContainers);
|
|
|
|
|
for (String type : spec.getTypes()) {
|
|
|
|
|
// 通过类型获取 beanName
|
|
|
|
|
Collection<String> typeMatches = getBeanNamesForType(classLoader, considerHierarchy, beanFactory, type,
|
|
|
|
|
parameterizedContainers);
|
|
|
|
|
typeMatches.removeAll(beansIgnoredByType);
|
|
|
|
|
if (typeMatches.isEmpty()) {
|
|
|
|
|
result.recordUnmatchedType(type);
|
|
|
|
|
}
|
|
|
|
|
else {
|
|
|
|
|
result.recordMatchedType(type, typeMatches);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
for (String annotation : spec.getAnnotations()) {
|
|
|
|
|
Set<String> annotationMatches = getBeanNamesForAnnotation(classLoader, beanFactory, annotation,
|
|
|
|
|
considerHierarchy);
|
|
|
|
|
annotationMatches.removeAll(beansIgnoredByType);
|
|
|
|
|
if (annotationMatches.isEmpty()) {
|
|
|
|
|
result.recordUnmatchedAnnotation(annotation);
|
|
|
|
|
}
|
|
|
|
|
else {
|
|
|
|
|
result.recordMatchedAnnotation(annotation, annotationMatches);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
for (String beanName : spec.getNames()) {
|
|
|
|
|
if (!beansIgnoredByType.contains(beanName) && containsBean(beanFactory, beanName, considerHierarchy)) {
|
|
|
|
|
result.recordMatchedName(beanName);
|
|
|
|
|
}
|
|
|
|
|
else {
|
|
|
|
|
result.recordUnmatchedName(beanName);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
return result;
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
- 在`MatchResult result = new MatchResult()` 之前的代码作用是确认 ioc 容器
|
|
|
|
|
|
|
|
|
|
#### getNamesOfBeansIgnoredByType
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
/**
|
|
|
|
|
* 获取忽略的beans(返回对象是 beanName)
|
|
|
|
|
* 循环,忽略的类型, 将类型从 beanFactory 获取,返回
|
|
|
|
|
*/
|
|
|
|
|
private Set<String> getNamesOfBeansIgnoredByType(ClassLoader classLoader, ListableBeanFactory beanFactory,
|
|
|
|
|
boolean considerHierarchy, Set<String> ignoredTypes, Set<Class<?>> parameterizedContainers) {
|
|
|
|
|
Set<String> result = null;
|
|
|
|
|
for (String ignoredType : ignoredTypes) {
|
|
|
|
|
// 从 beanFactory 中获取忽略的beanNames
|
|
|
|
|
Collection<String> ignoredNames = getBeanNamesForType(classLoader, considerHierarchy, beanFactory,
|
|
|
|
|
ignoredType, parameterizedContainers);
|
|
|
|
|
result = addAll(result, ignoredNames);
|
|
|
|
|
}
|
|
|
|
|
return (result != null) ? result : Collections.emptySet();
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
#### getBeanNamesForType
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
/**
|
|
|
|
|
* 通过类型获取 beanName
|
|
|
|
|
*/
|
|
|
|
|
private Set<String> getBeanNamesForType(ClassLoader classLoader, boolean considerHierarchy,
|
|
|
|
|
ListableBeanFactory beanFactory, String type, Set<Class<?>> parameterizedContainers) throws LinkageError {
|
|
|
|
|
try {
|
|
|
|
|
// 从beanFactory 中获取忽略的类 返回beanNanme
|
|
|
|
|
return getBeanNamesForType(beanFactory, considerHierarchy, resolve(type, classLoader),
|
|
|
|
|
parameterizedContainers);
|
|
|
|
|
}
|
|
|
|
|
catch (ClassNotFoundException | NoClassDefFoundError ex) {
|
|
|
|
|
return Collections.emptySet();
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
#### getBeanNamesForType
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
/**
|
|
|
|
|
* 通过类型获取 beanName
|
|
|
|
|
*/
|
|
|
|
|
private Set<String> getBeanNamesForType(ListableBeanFactory beanFactory, boolean considerHierarchy, Class<?> type,
|
|
|
|
|
Set<Class<?>> parameterizedContainers) {
|
|
|
|
|
// 获取beanName
|
|
|
|
|
Set<String> result = collectBeanNamesForType(beanFactory, considerHierarchy, type, parameterizedContainers,
|
|
|
|
|
null);
|
|
|
|
|
return (result != null) ? result : Collections.emptySet();
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
#### collectBeanNamesForType
|
|
|
|
|
|
|
|
|
|
- 这里最终回到了 spring beanFactory 的方法 getBeanNamesForType
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
private Set<String> collectBeanNamesForType(ListableBeanFactory beanFactory, boolean considerHierarchy,
|
|
|
|
|
Class<?> type, Set<Class<?>> parameterizedContainers, Set<String> result) {
|
|
|
|
|
result = addAll(result, beanFactory.getBeanNamesForType(type, true, false));
|
|
|
|
|
for (Class<?> container : parameterizedContainers) {
|
|
|
|
|
ResolvableType generic = ResolvableType.forClassWithGenerics(container, type);
|
|
|
|
|
result = addAll(result, beanFactory.getBeanNamesForType(generic, true, false));
|
|
|
|
|
}
|
|
|
|
|
if (considerHierarchy && beanFactory instanceof HierarchicalBeanFactory) {
|
|
|
|
|
BeanFactory parent = ((HierarchicalBeanFactory) beanFactory).getParentBeanFactory();
|
|
|
|
|
if (parent instanceof ListableBeanFactory) {
|
|
|
|
|
result = collectBeanNamesForType((ListableBeanFactory) parent, considerHierarchy, type,
|
|
|
|
|
parameterizedContainers, result);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
return result;
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
到这里需要忽略的 beanName 就全部找出来了
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
// 匹配类型在移除
|
|
|
|
|
for (String type : spec.getTypes()) {
|
|
|
|
|
// 通过类型获取 beanName
|
|
|
|
|
Collection<String> typeMatches = getBeanNamesForType(classLoader, considerHierarchy, beanFactory, type,
|
|
|
|
|
parameterizedContainers);
|
|
|
|
|
typeMatches.removeAll(beansIgnoredByType);
|
|
|
|
|
if (typeMatches.isEmpty()) {
|
|
|
|
|
result.recordUnmatchedType(type);
|
|
|
|
|
}
|
|
|
|
|
else {
|
|
|
|
|
result.recordMatchedType(type, typeMatches);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// 注解匹配删除忽略的beanname
|
|
|
|
|
for (String annotation : spec.getAnnotations()) {
|
|
|
|
|
Set<String> annotationMatches = getBeanNamesForAnnotation(classLoader, beanFactory, annotation,
|
|
|
|
|
considerHierarchy);
|
|
|
|
|
annotationMatches.removeAll(beansIgnoredByType);
|
|
|
|
|
if (annotationMatches.isEmpty()) {
|
|
|
|
|
result.recordUnmatchedAnnotation(annotation);
|
|
|
|
|
}
|
|
|
|
|
else {
|
|
|
|
|
result.recordMatchedAnnotation(annotation, annotationMatches);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
- 在忽略 bean 找到之后做一个类型移除的操作.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
### 返回值
|
|
|
|
|
|
|
|
|
|
- 在返回之前做一堆判断条件. 一旦符合条件这个地方会做一个 noMatch 的一个对象(`ConditionOutcome`) ，通过返回 match 对象`ConditionOutcome`
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
public static ConditionOutcome noMatch(ConditionMessage message) {
|
|
|
|
|
return new ConditionOutcome(false, message);
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
if (!matchResult.isAllMatched()) {
|
|
|
|
|
String reason = createOnBeanNoMatchReason(matchResult);
|
|
|
|
|
return ConditionOutcome.noMatch(spec.message().because(reason));
|
|
|
|
|
}
|
|
|
|
|
// 把注解解析出来获得文本
|
|
|
|
|
matchMessage = spec.message(matchMessage).found("bean", "beans").items(Style.QUOTE,
|
|
|
|
|
matchResult.getNamesOfAllMatches());
|
|
|
|
|
}
|
|
|
|
|
if (metadata.isAnnotated(ConditionalOnSingleCandidate.class.getName())) {
|
|
|
|
|
Spec<ConditionalOnSingleCandidate> spec = new SingleCandidateSpec(context, metadata, annotations);
|
|
|
|
|
MatchResult matchResult = getMatchingBeans(context, spec);
|
|
|
|
|
if (!matchResult.isAllMatched()) {
|
|
|
|
|
return ConditionOutcome.noMatch(spec.message().didNotFind("any beans").atAll());
|
|
|
|
|
}
|
|
|
|
|
else if (!hasSingleAutowireCandidate(context.getBeanFactory(), matchResult.getNamesOfAllMatches(),
|
|
|
|
|
spec.getStrategy() == SearchStrategy.ALL)) {
|
|
|
|
|
return ConditionOutcome.noMatch(spec.message().didNotFind("a primary bean from beans")
|
|
|
|
|
.items(Style.QUOTE, matchResult.getNamesOfAllMatches()));
|
|
|
|
|
}
|
|
|
|
|
matchMessage = spec.message(matchMessage).found("a primary bean from beans").items(Style.QUOTE,
|
|
|
|
|
matchResult.getNamesOfAllMatches());
|
|
|
|
|
}
|
|
|
|
|
if (metadata.isAnnotated(ConditionalOnMissingBean.class.getName())) {
|
|
|
|
|
Spec<ConditionalOnMissingBean> spec = new Spec<>(context, metadata, annotations,
|
|
|
|
|
ConditionalOnMissingBean.class);
|
|
|
|
|
MatchResult matchResult = getMatchingBeans(context, spec);
|
|
|
|
|
if (matchResult.isAnyMatched()) {
|
|
|
|
|
String reason = createOnMissingBeanNoMatchReason(matchResult);
|
|
|
|
|
return ConditionOutcome.noMatch(spec.message().because(reason));
|
|
|
|
|
}
|
|
|
|
|
matchMessage = spec.message(matchMessage).didNotFind("any beans").atAll();
|
|
|
|
|
}
|
|
|
|
|
return ConditionOutcome.match(matchMessage);
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- 到此结果封装完毕.回到方法`org.springframework.boot.autoconfigure.condition.SpringBootCondition#matches(org.springframework.context.annotation.ConditionContext, org.springframework.core.type.AnnotatedTypeMetadata)` 继续进行
|
|
|
|
|
- 再往后就继续执行 spring 的 bean 初始化咯
|
|
|
|
|
|
|
|
|
|
## MessageSourceAutoConfiguration
|
|
|
|
|
|
|
|
|
|
- 启动阶段的一个类运行解读
|
|
|
|
|
|
|
|
|
|
- `org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration`
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
@Configuration(proxyBeanMethods = false)
|
|
|
|
|
@ConditionalOnMissingBean(name = AbstractApplicationContext.MESSAGE_SOURCE_BEAN_NAME, search = SearchStrategy.CURRENT)
|
|
|
|
|
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
|
|
|
|
|
@Conditional(ResourceBundleCondition.class)
|
|
|
|
|
@EnableConfigurationProperties
|
|
|
|
|
public class MessageSourceAutoConfiguration {}
|
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
- 根据类的注解信息我们可以找到有`ResourceBundleCondition`
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- 获取类名或者方法名的结果是`MessageSourceAutoConfiguration`全路径
|
|
|
|
|
|
|
|
|
|
- 继续往下是一个比较的方法(是否符合 match)
|
|
|
|
|
|
|
|
|
|
`org.springframework.boot.autoconfigure.condition.SpringBootCondition#getMatchOutcome`这个方法是一个抽象方法子类实现
|
|
|
|
|
|
|
|
|
|
- 上图中红框内标注的类为`org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration.ResourceBundleCondition`
|
|
|
|
|
|
|
|
|
|
同时继承`org.springframework.boot.autoconfigure.condition.SpringBootCondition`
|
|
|
|
|
|
|
|
|
|
并且重写了方法`getMatchOutcome`
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
@Override
|
|
|
|
|
public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
|
|
|
|
|
// 从 容器中获取
|
|
|
|
|
String basename = context.getEnvironment().getProperty("spring.messages.basename", "messages");
|
|
|
|
|
// 从缓存中获取条件信息
|
|
|
|
|
ConditionOutcome outcome = cache.get(basename);
|
|
|
|
|
if (outcome == null) {
|
|
|
|
|
// 生成条件信息对象
|
|
|
|
|
outcome = getMatchOutcomeForBasename(context, basename);
|
|
|
|
|
// 放入缓存
|
|
|
|
|
cache.put(basename, outcome);
|
|
|
|
|
}
|
|
|
|
|
return outcome;
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
这个方法主要将比较信息放入,
|
|
|
|
|
|
|
|
|
|
- 后续的行为依然是判断是否匹配,匹配就创建.
|
|
|
|
|
|
|
|
|
|
## Spring Boot 启动阶段的自动注入
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
org.springframework.boot.autoconfigure.AutoConfigurationImportSelector#filter
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
```java
|
|
|
|
|
private List<String> filter(List<String> configurations, AutoConfigurationMetadata autoConfigurationMetadata) {
|
|
|
|
|
long startTime = System.nanoTime();
|
|
|
|
|
String[] candidates = StringUtils.toStringArray(configurations);
|
|
|
|
|
boolean[] skip = new boolean[candidates.length];
|
|
|
|
|
boolean skipped = false;
|
|
|
|
|
// 获取 AutoConfigurationImportFilter 相关配置
|
|
|
|
|
for (AutoConfigurationImportFilter filter : getAutoConfigurationImportFilters()) {
|
|
|
|
|
// 执行 aware 相关接口
|
|
|
|
|
invokeAwareMethods(filter);
|
|
|
|
|
// 是否可以初始化的结果
|
|
|
|
|
boolean[] match = filter.match(candidates, autoConfigurationMetadata);
|
|
|
|
|
for (int i = 0; i < match.length; i++) {
|
|
|
|
|
if (!match[i]) {
|
|
|
|
|
// 是否跳过
|
|
|
|
|
skip[i] = true;
|
|
|
|
|
candidates[i] = null;
|
|
|
|
|
skipped = true;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
if (!skipped) {
|
|
|
|
|
return configurations;
|
|
|
|
|
}
|
|
|
|
|
List<String> result = new ArrayList<>(candidates.length);
|
|
|
|
|
// 处理最终需要的类
|
|
|
|
|
for (int i = 0; i < candidates.length; i++) {
|
|
|
|
|
if (!skip[i]) {
|
|
|
|
|
result.add(candidates[i]);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
if (logger.isTraceEnabled()) {
|
|
|
|
|
int numberFiltered = configurations.size() - result.size();
|
|
|
|
|
logger.trace("Filtered " + numberFiltered + " auto configuration class in "
|
|
|
|
|
+ TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTime) + " ms");
|
|
|
|
|
}
|
|
|
|
|
return new ArrayList<>(result);
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
- 在这里有一个关注点 循环方法`getAutoConfigurationImportFilters()`
|
|
|
|
|
|
|
|
|
|
```JAVA
|
|
|
|
|
protected List<AutoConfigurationImportFilter> getAutoConfigurationImportFilters() {
|
|
|
|
|
return SpringFactoriesLoader.loadFactories(AutoConfigurationImportFilter.class, this.beanClassLoader);
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
在`spring.factories`文件中找到`AutoConfigurationImportFilter`后面的值
|
|
|
|
|
|
|
|
|
|
```properties
|
|
|
|
|
org.springframework.boot.autoconfigure.AutoConfigurationImportFilter=\
|
|
|
|
|
org.springframework.boot.autoconfigure.condition.OnBeanCondition,\
|
|
|
|
|
org.springframework.boot.autoconfigure.condition.OnClassCondition,\
|
|
|
|
|
org.springframework.boot.autoconfigure.condition.OnWebApplicationCondition
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
- 此时我们可以和前文的源码分析连接起来有一个完整的认识了
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- 最后来看整体类图
|
|
|
|
|
|
|
|
|
|
|
