Spring框架学习[注解扫描和读取Bean] - JAVA

ew ScannedGenericBeanDefinition(metadataReader); //设置Bean定义来源于resource

sbd.setResource(resource); //为元数据元素设置配置资源对象

sbd.setSource(resource); //检查Bean是否是一个可实例化的对象

if (isCandidateComponent(sbd)) { if (debugEnabled) {

logger.debug(Identified candidate component class: + resource); }

candidates.add(sbd); }

else { if (debugEnabled) {

logger.debug(Ignored because not a concrete top-level class: + resource); }

} }

else { if (traceEnabled) {

logger.trace(Ignored because not matching any filter: + resource); }

} }

catch (Throwable ex) { throw new BeanDefinitionStoreException(

Failed to read candidate component class: + resource, ex); }

} else {

if (traceEnabled) { logger.trace(Ignored because not readable: + resource);

} }

catch (IOException ex) { throw new BeanDefinitionStoreException(I/O failure during classpath scanning, ex);

} return candidates;

} //判断元信息读取器读取的类是否符合容器定义的注解过滤规则

protected boolean isCandidateComponent(MetadataReader metadataReader) throws IOException { //如果读取的类的注解在排除注解过滤规则中，返回false

for (TypeFilter tf : this.excludeFilters) { if (tf.match(metadataReader, this.metadataReaderFactory)) {

return false; }

} //如果读取的类的注解在包含的注解的过滤规则中，则返回ture

for (TypeFilter tf : this.includeFilters) { if (tf.match(metadataReader, this.metadataReaderFactory)) {

return true; }

} //如果读取的类的注解既不在排除规则，也不在包含规则中，则返回false

return false; }

…… }

5.AnnotationConfigWebApplicationContext载入注解Bean定义：

AnnotationConfigWebApplicationContext是AnnotationConfigApplicationContext的Web版，它们对于注解Bean的注册和扫描是基本相同的，但是AnnotationConfigWebApplicationContext对注解Bean定义的载入稍有不同，AnnotationConfigWebApplicationContext注入注解Bean定义源码如下：

[java] view plaincopy

//载入注解Bean定义资源 protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) {
//为容器设置注解Bean定义读取器 AnnotatedBeanDefinitionReader reader = new AnnotatedBeanDefinitionReader(beanFactory);
//为容器设置类路径Bean定义扫描器 ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(beanFactory);
//获取容器的Bean名称生成器 BeanNameGenerator beanNameGenerator = getBeanNameGenerator();
//获取容器的作用域元信息解析器 ScopeMetadataResolver scopeMetadataResolver = getScopeMetadataResolver();
//为注解Bean定义读取器和类路径扫描器设置Bean名称生成器 if (beanNameGenerator != null) {
reader.setBeanNameGenerator(beanNameGenerator); scanner.setBeanNameGenerator(beanNameGenerator);
} //为注解Bean定义读取器和类路径扫描器设置作用域元信息解析器
if (scopeMetadataResolver != null) { reader.setScopeMetadataResolver(scopeMetadataResolver);
scanner.setScopeMetadataResolver(scopeMetadataResolver); }
//获取容器定义的Bean定义资源路径 String[] configLocations = getConfigLocations();
//如果定位的Bean定义资源路径不为空 if (configLocations != null) {
for (String configLocation : configLocations) { try {
//使用当前容器的类加载器加载定位路径的字节码类文件 Class clazz = getClassLoader().loadClass(configLocation);
if (logger.isInfoEnabled()) { logger.info(Successfully resolved class for [ + configLocation + ]);
} reader.register(clazz);
} catch (ClassNotFoundException ex) {
if (logger.isDebugEnabled()) { logger.debug(Could not load class for config location [ + configLocation +
] - trying package scan. + ex); }
//如果容器类加载器加载定义路径的Bean定义资源失败，则启用 //容器类路径扫描器扫描给定路径包及其子包中的类
int count = scanner.scan(configLocation); if (logger.isInfoEnabled()) {
if (count == 0) { logger.info(No annotated classes found for specified class/package [

Spring框架学习[注解扫描和读取Bean](七)