diff --git a/spring-context/pom.xml b/spring-context/pom.xml index 5de49a4..2e01b1e 100644 --- a/spring-context/pom.xml +++ b/spring-context/pom.xml @@ -11,8 +11,10 @@ 4.0.0 spring-context pom + spring-context-classPathXmlApplicationContext + spring-context-annotationConfigApplicationContext \ No newline at end of file diff --git a/spring-context/spring-context-annotationConfigApplicationContext/README.md b/spring-context/spring-context-annotationConfigApplicationContext/README.md new file mode 100644 index 0000000..5073595 --- /dev/null +++ b/spring-context/spring-context-annotationConfigApplicationContext/README.md @@ -0,0 +1,166 @@ +## AnnotationConfigApplicationContext + +- [AnnotationConfigApplicationContext](#annotationconfigapplicationcontext) + - [一、基本信息](#一基本信息) + - [二、知识储备](#二知识储备) + - [三、基本描述](#三基本描述) + - [四、最佳实践](#四最佳实践) + - [五、时序图](#五时序图) + - [六、源码分析](#六源码分析) + + +### 一、基本信息 + +✒️ **作者** - Lex 📝 **博客** - [掘金](https://juejin.cn/user/4251135018533068/posts) 📚 **源码地址** - [github](https://github.com/xuchengsheng/spring-reading) + +### 二、知识储备 + ++ **ClassPathBeanDefinitionScanner** + + [ClassPathBeanDefinitionScanner](https://github.com/xuchengsheng/spring-reading/blob/master/spring-beans/spring-bean-classPathBeanDefinitionScanner/README.md) 类，用于在类路径上扫描指定包及其子包中的类，识别符合条件的类，并将其注册为 Spring Bean 的定义，从而实现组件扫描和自动装配，使我们能够方便地管理和配置应用程序中的 Bean。它允许我们定义过滤条件，以确定哪些类应被注册为 Bean，以及配合自动装配实现依赖注入，提高了应用程序的可维护性和扩展性。 ++ **AnnotatedBeanDefinitionReader** + + [AnnotatedBeanDefinitionReader](https://github.com/xuchengsheng/spring-reading/blob/master/spring-beans/spring-bean-annotatedBeanDefinitionReader/README.md)是一个用于读取和解析带有注解的Bean定义的类，它主要用于基于注解的配置方式，允许开发者将Java类标记为Spring组件，从而让Spring容器自动扫描和注册这些组件，而不需要显式配置这些组件的Bean定义。 + +### 三、基本描述 + +`AnnotationConfigApplicationContext` 提供了一种基于 Java 注解的轻量级、类型安全的方式来配置和管理 Spring 容器中的 bean。这种方式相对于传统的 XML 配置方式更加灵活，并且有助于减少配置文件的数量和复杂性。 + +### 四、最佳实践 + +通过`AnnotationConfigApplicationContext`容器，以手动注册和包扫描两种方式注册Bean定义，其中手动注册了单个Bean（`MyBean`类），并通过包扫描注册了指定包路径下的所有标有`@Component`及其派生注解的类。最后，通过打印输出了所有已注册的Bean定义的名称。 + +```java +public class RegisterBeanDefinitionApplication { + + public static void main(String[] args) { + AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(); + // 注册Bean + context.register(MyBean.class); + // 扫描包 + context.scan("com.xcs.spring"); + // 打印Bean定义 + for (String beanDefinitionName : context.getBeanDefinitionNames()) { + System.out.println("beanDefinitionName = " + beanDefinitionName); + } + } +} +``` + +一个简单的Java类 `MyBean`，这个类没有任何注解或其他特殊标记。 + +```java +public class MyBean { + +} +``` + +分别使用`@Controller`、`@Service`和`@Repository`。这些注解是Spring框架中用于标识不同层次组件的特殊注解。 + +```java +@Controller +public class MyController { + +} + +@Service +public class MyService { + +} + +@Repository +public class MyRepository { + +} +``` + +运行结果发现，Spring应用上下文中成功加载了配置，并注册了各种Bean定义，包括手动注册和通过注解自动注册的。 + +PS：前面4个是Spring容器内部的注册的Bean定义。 + +```java +beanDefinitionName = org.springframework.context.annotation.internalConfigurationAnnotationProcessor +beanDefinitionName = org.springframework.context.annotation.internalAutowiredAnnotationProcessor +beanDefinitionName = org.springframework.context.event.internalEventListenerProcessor +beanDefinitionName = org.springframework.context.event.internalEventListenerFactory +beanDefinitionName = myBean +beanDefinitionName = myController +beanDefinitionName = myRepository +beanDefinitionName = myService +``` + +### 五、时序图 + +~~~mermaid +sequenceDiagram +Title: AnnotationConfigApplicationContext时序图 + +AnnotationConfigApplicationContextDemo->>AnnotationConfigApplicationContext: AnnotationConfigApplicationContext() +Note over AnnotationConfigApplicationContextDemo,AnnotationConfigApplicationContext: 创建 AnnotationConfigApplicationContext 实例 + +AnnotationConfigApplicationContext->>AnnotatedBeanDefinitionReader: new AnnotatedBeanDefinitionReader(this) +Note over AnnotationConfigApplicationContext,AnnotatedBeanDefinitionReader: 创建 AnnotatedBeanDefinitionReader 实例 + +AnnotatedBeanDefinitionReader->>AnnotationConfigApplicationContext: 返回 AnnotatedBeanDefinitionReader +Note over AnnotatedBeanDefinitionReader,AnnotationConfigApplicationContext: 获取 AnnotatedBeanDefinitionReader 实例 + +AnnotationConfigApplicationContext->>ClassPathBeanDefinitionScanner: new ClassPathBeanDefinitionScanner(this) +Note over AnnotationConfigApplicationContext,ClassPathBeanDefinitionScanner: 创建 ClassPathBeanDefinitionScanner 实例 + +ClassPathBeanDefinitionScanner->>AnnotationConfigApplicationContext: 返回 ClassPathBeanDefinitionScanner +Note over ClassPathBeanDefinitionScanner,AnnotationConfigApplicationContext: 获取 ClassPathBeanDefinitionScanner 实例 + +AnnotationConfigApplicationContextDemo->>AnnotationConfigApplicationContext: register(componentClasses) +Note over AnnotationConfigApplicationContextDemo,AnnotationConfigApplicationContext: 注册组件类 + +AnnotationConfigApplicationContext->>AnnotatedBeanDefinitionReader: this.reader.register(componentClasses) +Note over AnnotationConfigApplicationContext,AnnotatedBeanDefinitionReader: 使用 AnnotatedBeanDefinitionReader 注册组件类 + +AnnotationConfigApplicationContextDemo->>AnnotationConfigApplicationContext: scan(basePackages) +Note over AnnotationConfigApplicationContextDemo,AnnotationConfigApplicationContext: 扫描指定包 + +AnnotationConfigApplicationContext->>ClassPathBeanDefinitionScanner: this.scanner.scan(basePackages) +Note over AnnotationConfigApplicationContext,ClassPathBeanDefinitionScanner: 使用 ClassPathBeanDefinitionScanner 扫描包 + +~~~ + +### 六、源码分析 + +在`org.springframework.context.annotation.AnnotationConfigApplicationContext#AnnotationConfigApplicationContext()`方法中，初始化`AnnotationConfigApplicationContext`实例中的两个关键组件：`AnnotatedBeanDefinitionReader`和`ClassPathBeanDefinitionScanner`，这两者分别用于处理注解式Bean定义和类路径扫描注册Bean定义。 + +```java +public AnnotationConfigApplicationContext() { + StartupStep createAnnotatedBeanDefReader = this.getApplicationStartup().start("spring.context.annotated-bean-reader.create"); + this.reader = new AnnotatedBeanDefinitionReader(this); + createAnnotatedBeanDefReader.end(); + this.scanner = new ClassPathBeanDefinitionScanner(this); +} +``` + +在`org.springframework.context.annotation.AnnotationConfigApplicationContext#register`方法中，主要作用是通过`AnnotatedBeanDefinitionReader`注册一组组件类，将它们解析为Spring容器中的Bean定义。 + +> **`this.reader.register(componentClasses)`方法的源码分析已经在另外一篇关于[AnnotatedBeanDefinitionReader](https://github.com/xuchengsheng/spring-reading/blob/master/spring-beans/spring-bean-annotatedBeanDefinitionReader/README.md)类的博客中详细分析了。** + +```java +@Override +public void register(Class... componentClasses) { + Assert.notEmpty(componentClasses, "At least one component class must be specified"); + StartupStep registerComponentClass = this.getApplicationStartup().start("spring.context.component-classes.register") + .tag("classes", () -> Arrays.toString(componentClasses)); + this.reader.register(componentClasses); + registerComponentClass.end(); +} +``` + +在`org.springframework.context.annotation.AnnotationConfigApplicationContext#scan`方法中，主要作用是通过`ClassPathBeanDefinitionScanner`扫描指定的基础包路径下的类，将它们解析为Spring容器中的Bean定义。 + +> **`this.scanner.scan(basePackages)`方法的源码分析已经在另外一篇关于[ClassPathBeanDefinitionScanner](https://github.com/xuchengsheng/spring-reading/blob/master/spring-beans/spring-bean-classPathBeanDefinitionScanner/README.md)类的博客中详细分析了。** + +```java +@Override +public void scan(String... basePackages) { + Assert.notEmpty(basePackages, "At least one base package must be specified"); + StartupStep scanPackages = this.getApplicationStartup().start("spring.context.base-packages.scan") + .tag("packages", () -> Arrays.toString(basePackages)); + this.scanner.scan(basePackages); + scanPackages.end(); +} +``` \ No newline at end of file diff --git a/spring-context/spring-context-annotationConfigApplicationContext/pom.xml b/spring-context/spring-context-annotationConfigApplicationContext/pom.xml new file mode 100644 index 0000000..5bbabd1 --- /dev/null +++ b/spring-context/spring-context-annotationConfigApplicationContext/pom.xml @@ -0,0 +1,14 @@ + + + + spring-context + com.xcs.spring + 0.0.1-SNAPSHOT + + + 4.0.0 + spring-context-annotationConfigApplicationContext + + \ No newline at end of file diff --git a/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/AnnotationConfigApplicationContextDemo.java b/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/AnnotationConfigApplicationContextDemo.java new file mode 100644 index 0000000..d790785 --- /dev/null +++ b/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/AnnotationConfigApplicationContextDemo.java @@ -0,0 +1,23 @@ +package com.xcs.spring; + +import com.xcs.spring.bean.MyBean; +import org.springframework.context.annotation.AnnotationConfigApplicationContext; + +/** + * @author xcs + * @date 2023年11月23日 18时06分 + **/ +public class AnnotationConfigApplicationContextDemo { + + public static void main(String[] args) { + AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(); + // 注册Bean + context.register(MyBean.class); + // 扫描包 + context.scan("com.xcs.spring"); + // 打印Bean定义 + for (String beanDefinitionName : context.getBeanDefinitionNames()) { + System.out.println("beanDefinitionName = " + beanDefinitionName); + } + } +} diff --git a/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/bean/MyBean.java b/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/bean/MyBean.java new file mode 100644 index 0000000..d9c10bb --- /dev/null +++ b/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/bean/MyBean.java @@ -0,0 +1,8 @@ +package com.xcs.spring.bean; + +/** + * @author xcs + * @date 2023年11月22日 11时23分 + **/ +public class MyBean { +} diff --git a/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/controller/MyController.java b/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/controller/MyController.java new file mode 100644 index 0000000..1e08b24 --- /dev/null +++ b/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/controller/MyController.java @@ -0,0 +1,11 @@ +package com.xcs.spring.controller; + +import org.springframework.stereotype.Controller; + +/** + * @author xcs + * @date 2023年11月07日 17时47分 + **/ +@Controller +public class MyController { +} diff --git a/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/repository/MyRepository.java b/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/repository/MyRepository.java new file mode 100644 index 0000000..ec8ba76 --- /dev/null +++ b/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/repository/MyRepository.java @@ -0,0 +1,11 @@ +package com.xcs.spring.repository; + +import org.springframework.stereotype.Repository; + +/** + * @author xcs + * @date 2023年11月07日 17时46分 + **/ +@Repository +public class MyRepository { +} diff --git a/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/service/MyService.java b/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/service/MyService.java new file mode 100644 index 0000000..5c9b22f --- /dev/null +++ b/spring-context/spring-context-annotationConfigApplicationContext/src/main/java/com/xcs/spring/service/MyService.java @@ -0,0 +1,11 @@ +package com.xcs.spring.service; + +import org.springframework.stereotype.Service; + +/** + * @author xcs + * @date 2023年11月07日 17时46分 + **/ +@Service +public class MyService { +}