{"id":18876671,"url":"https://github.com/ifan112/demo-spring-context","last_synced_at":"2026-05-17T06:34:37.090Z","repository":{"id":101766555,"uuid":"172507787","full_name":"ifan112/demo-spring-context","owner":"ifan112","description":"spring-context学习项目","archived":false,"fork":false,"pushed_at":"2019-03-06T08:42:20.000Z","size":204,"stargazers_count":0,"open_issues_count":0,"forks_count":0,"subscribers_count":0,"default_branch":"master","last_synced_at":"2025-06-13T10:02:39.145Z","etag":null,"topics":["java","spring"],"latest_commit_sha":null,"homepage":null,"language":"Java","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/ifan112.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null}},"created_at":"2019-02-25T13:07:30.000Z","updated_at":"2019-03-06T08:42:21.000Z","dependencies_parsed_at":"2023-07-17T02:16:04.845Z","dependency_job_id":null,"html_url":"https://github.com/ifan112/demo-spring-context","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/ifan112/demo-spring-context","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ifan112%2Fdemo-spring-context","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ifan112%2Fdemo-spring-context/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ifan112%2Fdemo-spring-context/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ifan112%2Fdemo-spring-context/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/ifan112","download_url":"https://codeload.github.com/ifan112/demo-spring-context/tar.gz/refs/heads/master","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ifan112%2Fdemo-spring-context/sbom","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":259624728,"owners_count":22886327,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["java","spring"],"created_at":"2024-11-08T06:14:49.112Z","updated_at":"2025-10-19T18:04:54.771Z","avatar_url":"https://github.com/ifan112.png","language":"Java","funding_links":[],"categories":[],"sub_categories":[],"readme":"# Condition相关用法\n\nspring在注册bean时，允许开发者自定义注册条件，即只在满足某些条件时才注册该bean，不符合指定条件的情况下取消注册bean。该特性关联的有@Conditional注解与ConfigurationCondition接口。\n\n#### 用法\n\n自定义类实现ConfigurationCondition接口，重写matches和getConfigurationPhase方法。\n\n```java\nclass OrderServiceCondition implements ConfigurationCondition {\n    @Override\n    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {\n        // 这里简单点返回false，表示任何条件都不满足，不要注册该bean\n        return false;\n    }\n\n    @Override\n    public ConfigurationPhase getConfigurationPhase() {\n        // 判断条件发生的阶段，这里是在配置阶段判断是否满足条件\n        return ConfigurationPhase.PARSE_CONFIGURATION;\n    }\n}\n```\n\n然后，在待注册的bean class上使用注解@Conditional，设置该注解的value方法返回值为自定义类。\n\n```java\n@Service\n@Conditional(OrderServiceCondition.class)\npublic class OrderService {\n}\n```\n\n此后，在向beanFactory注册该bean时，spring会首先检查是否满足注册条件。不满足（即matches方法返回false）就取消注册。\n\n### 源码解析\n\n```java\npublic class AnnotatedBeanDefinitionReader {\n    // 条件评估器\n    private ConditionEvaluator conditionEvaluator;\n    \n    public void registerBean(Class\u003c?\u003e annotatedClass) {\n        doRegisterBean(annotatedClass, null, null, null);\n    }\n    \n    \u003cT\u003e void doRegisterBean(Class\u003cT\u003e annotatedClass, \n                            @Nullable Supplier\u003cT\u003e instanceSupplier, \n                            @Nullable String name,\n                            @Nullable Class\u003c? extends Annotation\u003e[] qualifiers,\n                            BeanDefinitionCustomizer... definitionCustomizers) {\n        AnnotatedGenericBeanDefinition abd = new AnnotatedGenericBeanDefinition(annotatedClass);\n        \n        // 判断当前是否满足bean的注册条件\n        // if (this.conditionEvaluator.shouldSkip(abd.getMetadata())) {\n            // 不满足不注册，直接返回\n            return;\n        }\n        \n        // ... 继续注册bean\n}\n\npublic class ConditionEvaluator { \n    public boolean shouldSkip(AnnotatedTypeMetadata metadata) { \n        return shouldSkip(metadata, null); \n    }\n    \n    public boolean shouldSkip(@Nullable AnnotatedTypeMetadata metadata,\n                              @Nullable ConfigurationPhase phase) {\n        if (metadata == null || !metadata.iaAnnotated(Conditional.class.getName())) {\n            // 如果bean没有@Conditional注解，那么不用判断直接注册该bean\n            return false;\n        }\n        \n        if (phase == null) {\n            if (metadata instanceof AnnotationMetadata \u0026\u0026\n                ConfigurationClassUtils.isConfigurationCandidate(metadata)) {\n                // 如果该bean是一个注解类，且有@Configuration注解，则猜测是解析配置阶段\n                return shouldSkip(metadata, ConfigurationPhase.PARSE_CONFIGURATION);\n            }\n            // 否则，是注册bean阶段\n            return shouldSkip(metadata, ConfigurationPhase.REGISTER_BEAN);\n        }\n        \n        List\u003cCondition\u003e conditions = new ArrayList\u003c\u003e();\n        // 遍历bean上的@Conditional注解使用Condition实现类名称\n        for (String[] conditionClasses : getConditionClasses(metadata)) {\n            for (String conditionClass : conditionClasses) {\n                // 加载Condition实现类\n                Condition condition\n                    = getCondition(conditionClass, this.context.getClassLoader());\n                conditions.add(condition);\n            }\n        }\n        \n        // 对条件列表排序\n        AnnotationAwareOrderComparator.sort(conditions);\n        \n        for (Condition condition : conditions) {\n            ConfigurationPhase requiredPhase = null;\n            if (condition instanceof CondigurationCondition) {\n                requiredPhase \n                    = ((ConfigurationCondition) condition).getConfigurationPhase();\n            }\n            if ((requiredPhase == null || requiredPhase == phase)\n                \u0026\u0026 !condition.matches(this.context, metadata)) {\t// 判断当前条件是否满足\n                // 如果当前条件不满足，则返回true，表示要跳过注册bean\n                return true;\n            }\n        }\n        \n        return false;\n    }\n}\n```\n\n\n\n# bean名称\n\n开发者在使用@Service，@Component等等注解时，可以指定bean名称。如果没有指定，spring容器将会生成一个默认的bean名称。默认规则通常是首字母小写的bean类名称。\n\n#### 源码解析\n\n```java\npublic class AnnotationBeanNameGenerator implements BeanNameGenerator { \n    // 生成bean的名称\n    public String generateBeanName(BeanDefinition definition, \n                                   BeanDefinitionRegistry registry) {\n        if (definition instanceof AnnotatedBeanDefition) {\n            // 如果该bean是一个基于注解配置的类，那么尝试获取该bean的@Component、@ManagedBean、@Named\n            // 注解的value()方法返回值，如果该返回值是string且非空，则以该string作为bean的名称\n            String beanName \n                = determineBeanNameFromAnnotation((AnnotatedBeanDefintion) definition);\n            if (StringUtils.hasText(beanName)) {\n                return beanName;\n            }\n        }\n\n        // 默认生成beanFactory全局唯一的bean名称\n        return buildDefaultBeanName(definition);\n    }\n    \n    @Override\n    protected String determineBeanNameFromAnnotation(AnnotatedBeanDefinition annotatedDef) {\n        AnnotationMetadata amd = annotatedDef.getMetadata();\n        Set\u003cString\u003e types = amd.getAnnotationTypes();\n        String beanName = null;\n        // 遍历注解\n        for (String type : types) {\n            AnnotationAttributes attributes \n                = AnnotationConfigUtils.attributesFor(amd, type);\n            // 判断注解是不是@Component、@ManagedBean、@Named，且是否有value()方法\n            if (attributes != null \u0026\u0026 isStereotypeWithNameValue(type, amd.getMetaAnnotationTypes(type), attributes)) {\n                // 获取这些注解的value()方法返回值，如果返回值是string类型，\n                // 且返回值是非空字符，则以该名称作为bean名称\n                Object value = attributes.get(\"value\");\n                if (value instanceof String) {\n                    String strVal = (String) value;\n                    if (StringUtils.hasLength(strVal)) {\n                        if (beanName != null \u0026\u0026 !strVal.equals(beanName)) {\n                            // 已经有名称了，抛出异常\n                        }\n                        beanName = strVal;\n                    }\n                }\n            }\n        }\n        return beanName;\n    }\n\n    // 判断注解是不是@Component、@ManagedBean、@Named，且是否有value()方法\n    protected boolean isStereotypeWithNameValue(String annotationType,\n                                                Set\u003cString\u003e metaAnnotationTypes,\n                                                @Nullable Map\u003cString, Object\u003e attributes) {\n    \tboolean isStereotype \n        \t= annotationType.equals(\"org.springframework.stereotype.Component\") ||\n            \tmetaAnnotationTypes.contains(\"org.springframework.stereotype.Component\") ||\n            \tannotationType.equals(\"javax.annotation.ManagedBean\") ||\n            \tannotationType.equals(\"javax.inject.Named\");\n\n    \treturn (isStereotype \u0026\u0026 attributes != null \u0026\u0026 attributes.containsKey(\"value\")); \n    }\n    \n    // 创建默认的bean名称\n    protected String buildDefaultBeanName(BeanDefinition definition) {\n        // 含有路径的全限定的类名\n        String beanClassName = definition.getBeanClassName();\n        // 类名\n        String shortClassName = ClassUtils.getShortName(beanClassName) {\n            int lastDotIndex = className.lastIndexOf(\".\");\n            // 处理cglib生成类的带有$$字符的类名称 \n            int nameEndIndex = className.indexOf(\"$$\");\n            if (nameEndIndex == -1) {\n                nameEndIndex = className.length();\n            }\n            String shortName = className.substring(lastDotIndex + 1, nameEndIndex);\n            shortName = shortName.replace(INNER_CLASS_SEPARATOR, PACKAGE_SEPARATOR);\n            return shortName;\n        };\n        // 返回首字母小写\n        return Introspector.decapitialize(shortClassName); \n    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