From 8eff3d61d7209b039d340ca9779bee9925698b6a Mon Sep 17 00:00:00 2001 From: xuchengsheng Date: Wed, 22 Nov 2023 11:49:52 +0800 Subject: [PATCH] =?UTF-8?q?Bean=E7=9A=84=E5=AE=9A=E4=B9=89=E6=B3=A8?= =?UTF-8?q?=E5=86=8C?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- spring-core/pom.xml | 1 + .../README.md | 125 ++++++++++++++++++ .../pom.xml | 14 ++ .../RegisterBeanDefinitionApplication.java | 23 ++++ .../main/java/com/xcs/spring/bean/MyBean.java | 8 ++ .../xcs/spring/controller/MyController.java | 11 ++ .../xcs/spring/repository/MyRepository.java | 11 ++ .../com/xcs/spring/service/MyService.java | 11 ++ 8 files changed, 204 insertions(+) create mode 100644 spring-core/spring-core-registerBeanDefinition/README.md create mode 100644 spring-core/spring-core-registerBeanDefinition/pom.xml create mode 100644 spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/RegisterBeanDefinitionApplication.java create mode 100644 spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/bean/MyBean.java create mode 100644 spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/controller/MyController.java create mode 100644 spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/repository/MyRepository.java create mode 100644 spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/service/MyService.java diff --git a/spring-core/pom.xml b/spring-core/pom.xml index bef01e8..b8b9593 100644 --- a/spring-core/pom.xml +++ b/spring-core/pom.xml @@ -15,6 +15,7 @@ spring-core-getBean spring-core-resolveDependency + spring-core-registerBeanDefinition \ No newline at end of file diff --git a/spring-core/spring-core-registerBeanDefinition/README.md b/spring-core/spring-core-registerBeanDefinition/README.md new file mode 100644 index 0000000..8aa889c --- /dev/null +++ b/spring-core/spring-core-registerBeanDefinition/README.md @@ -0,0 +1,125 @@ +## Bean的定义注册 + +- [Bean的定义注册](#bean的定义注册) + - [一、基本信息](#一基本信息) + - [二、知识储备](#二知识储备) + - [三、最佳实践](#三最佳实践) + - [四、源码分析](#四源码分析) + + +### 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、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 +``` + +### 四、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。 + +> **具体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。 + +> **具体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-core/spring-core-registerBeanDefinition/pom.xml b/spring-core/spring-core-registerBeanDefinition/pom.xml new file mode 100644 index 0000000..148be0b --- /dev/null +++ b/spring-core/spring-core-registerBeanDefinition/pom.xml @@ -0,0 +1,14 @@ + + + + spring-core + com.xcs.spring + 0.0.1-SNAPSHOT + + + 4.0.0 + spring-core-registerBeanDefinition + + \ No newline at end of file diff --git a/spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/RegisterBeanDefinitionApplication.java b/spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/RegisterBeanDefinitionApplication.java new file mode 100644 index 0000000..ab4a11a --- /dev/null +++ b/spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/RegisterBeanDefinitionApplication.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22日 09时58分 + **/ +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); + } + } +} diff --git a/spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/bean/MyBean.java b/spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/bean/MyBean.java new file mode 100644 index 0000000..d9c10bb --- /dev/null +++ b/spring-core/spring-core-registerBeanDefinition/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-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/controller/MyController.java b/spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/controller/MyController.java new file mode 100644 index 0000000..1e08b24 --- /dev/null +++ b/spring-core/spring-core-registerBeanDefinition/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-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/repository/MyRepository.java b/spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/repository/MyRepository.java new file mode 100644 index 0000000..ec8ba76 --- /dev/null +++ b/spring-core/spring-core-registerBeanDefinition/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-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/service/MyService.java b/spring-core/spring-core-registerBeanDefinition/src/main/java/com/xcs/spring/service/MyService.java new file mode 100644 index 0000000..5c9b22f --- /dev/null +++ b/spring-core/spring-core-registerBeanDefinition/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 { +}