解析
- 相关类: org.springframework.context.index.CandidateComponentsIndexLoader
- 测试用例: org.springframework.context.annotation.ClassPathScanningCandidateComponentProviderTests.defaultsWithIndex,org.springframework.context.index.CandidateComponentsIndexLoaderTests
- CandidateComponentsIndexLoader是怎么找出来的,全文搜索spring.components
使用介绍
- 下面是从resources/example/scannable/spring.components测试用例中复制过来的,从中可以发现等号左侧放的是我们写的组件,等号右边是属于什么组件
example.scannable.AutowiredQualifierFooService=example.scannable.FooService example.scannable.DefaultNamedComponent=org.springframework.stereotype.Component example.scannable.NamedComponent=org.springframework.stereotype.Component example.scannable.FooService=example.scannable.FooService example.scannable.FooServiceImpl=org.springframework.stereotype.Component,example.scannable.FooService example.scannable.ScopedProxyTestBean=example.scannable.FooService example.scannable.StubFooDao=org.springframework.stereotype.Component example.scannable.NamedStubDao=org.springframework.stereotype.Component example.scannable.ServiceInvocationCounter=org.springframework.stereotype.Component example.scannable.sub.BarComponent=org.springframework.stereotype.ComponentCopy to clipboardErrorCopied
debug
- 入口 org.springframework.context.index.CandidateComponentsIndexLoader.loadIndex
@Nullable public static CandidateComponentsIndex loadIndex(@Nullable ClassLoader classLoader) { ClassLoader classLoaderToUse = classLoader; if (classLoaderToUse == null) { classLoaderToUse = CandidateComponentsIndexLoader.class.getClassLoader(); } return cache.computeIfAbsent(classLoaderToUse, CandidateComponentsIndexLoader::doLoadIndex); } Copy to clipboardErrorCopied
/** * 解析 META-INF/spring.components 文件 * @param classLoader * @return */ @Nullable private static CandidateComponentsIndex doLoadIndex(ClassLoader classLoader) { if (shouldIgnoreIndex) { return null; } try { Enumeration<URL> urls = classLoader.getResources(COMPONENTS_RESOURCE_LOCATION); if (!urls.hasMoreElements()) { return null; } List<Properties> result = new ArrayList<>(); while (urls.hasMoreElements()) { URL url = urls.nextElement(); // 读取META-INF/spring.components文件转换成map对象 Properties properties = PropertiesLoaderUtils.loadProperties(new UrlResource(url)); result.add(properties); } if (logger.isDebugEnabled()) { logger.debug("Loaded " + result.size() + "] index(es)"); } int totalCount = result.stream().mapToInt(Properties::size).sum(); // 查看CandidateComponentsIndex方法 return (totalCount > 0 ? new CandidateComponentsIndex(result) : null); } catch (IOException ex) { throw new IllegalStateException("Unable to load indexes from location [" + COMPONENTS_RESOURCE_LOCATION + "]", ex); } } Copy to clipboardErrorCopied
CandidateComponentsIndex(List<Properties> content) { this.index = parseIndex(content); } /** * 解析 MATE-INF\spring.components 转换成 map * * @param content * @return */ private static MultiValueMap<String, Entry> parseIndex(List<Properties> content) { MultiValueMap<String, Entry> index = new LinkedMultiValueMap<>(); for (Properties entry : content) { entry.forEach((type, values) -> { String[] stereotypes = ((String) values).split(","); for (String stereotype : stereotypes) { index.add(stereotype, new Entry((String) type)); } }); } return index; }Copy to clipboardErrorCopied
- 该类给org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider.findCandidateComponents提供了帮助
public Set<BeanDefinition> findCandidateComponents(String basePackage) { // 扫描 /** * if 测试用例: {@link org.springframework.context.annotation.ClassPathScanningCandidateComponentProviderTests#defaultsWithIndex()} * 解析 spring.components文件 */ if (this.componentsIndex != null && indexSupportsIncludeFilters()) { return addCandidateComponentsFromIndex(this.componentsIndex, basePackage); } else { return scanCandidateComponents(basePackage); } }
