springboot个性化Bean加载

阳光穿透心脏的1/2处 2023-06-16 01:55 15阅读 0赞

目的：项目功能实现分标准实现和个性实现，当启用个性实现时，则需要个性化bean处理业务。

参考自某大神的思路，也可以封装为自定义的starter，供其他模块服务

# 1.准备 #

代码结构：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xpYW5nQ0pQ_size_16_color_FFFFFF_t_70][]

pom文件：

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <groupId>com.me</groupId>
        <artifactId>personnalize</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>personnalize</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
        </properties>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.2.1.RELEASE</version>
            <relativePath/>
        </parent>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.16.22</version>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
    </project>

配置文件application.yml：

#项目名称，default表示标准， ICBC , BOC 标识个性项目
    personalise:
      projectName: BOC

2. 代码实现

/**
     * ClassName: PersonaliseComponentScan
     *
     * @Author: ME
     * Description:个性化bean注解
     */
    @Documented
    @Target(ElementType.TYPE)
    @Retention(RetentionPolicy.RUNTIME)
    @Import(CustomComponentRegistrar.class)
    public @interface PersonaliseComponentScan {
        /**
         * 扫描包路径,为空表示默认扫描个性化路径
         */
        String basePackage() default "";
    }

/**
     * ClassName: CustomComponentRegistrar
     *
     * @Author: ME
     * Description:自定义Spring bean注册器
     */
    
    @Slf4j
    public class CustomComponentRegistrar implements ImportBeanDefinitionRegistrar, EnvironmentAware {
        private static final String PERSONALIZE_PROJECT_PACKAGE = ".project.";
        private static final String PROJECT_NAME_PROPERTIES = "personalise.projectName";
        private static final String PROJECT_STANDARD = "default";
        private Environment environment;
    
        @Override
        public void setEnvironment(Environment environment) {
            this.environment = environment;
        }
    
        @Override
        public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
            // 读取注解 SpringBootApplication 的包内容
            Class<?> introspectedClass = ((StandardAnnotationMetadata) importingClassMetadata).getIntrospectedClass();
            String originBasePackageName = introspectedClass.getPackage().getName();
            AnnotationAttributes annoAttrs = AnnotationAttributes.fromMap(importingClassMetadata.getAnnotationAttributes(PersonaliseComponentScan.class.getName()));
            String projectName = environment.getProperty(PROJECT_NAME_PROPERTIES);
            String annotationBasePackage = annoAttrs.getString("basePackage");
            if (!StringUtils.isEmpty(annotationBasePackage) && !annotationBasePackage.equals(originBasePackageName)) {
                String applicationName = introspectedClass.getName();
                log.warn("@PersonaliseComponentScan 的 basePackage 配置 与 {} 所在包路径不一致", applicationName);
            }
            if (StringUtils.isEmpty(annotationBasePackage)) {
                annotationBasePackage = originBasePackageName;
            }
            DefaultListableBeanFactory beanFactory = (DefaultListableBeanFactory) registry;
            this.replacePersonaliseBean(projectName, annotationBasePackage, beanFactory);
        }
    
    
        private void replacePersonaliseBean(String projectName, String annotationBasePackage, DefaultListableBeanFactory beanFactory) {
            boolean useStandard = PROJECT_STANDARD.equals(projectName);
            for (String beanDefinitionName : beanFactory.getBeanDefinitionNames()) {
                BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanDefinitionName);
                // 个性化Bean替换
                if (beanDefinition instanceof ScannedGenericBeanDefinition && !useStandard) {
                    String beanClassName = beanDefinition.getBeanClassName();
                    //处理包名
                    String replace = Objects.requireNonNull(beanClassName).replace(annotationBasePackage, annotationBasePackage + PERSONALIZE_PROJECT_PACKAGE + projectName);
                    //处理类名
                    String className =projectName+replace.substring(replace.lastIndexOf(".")+1); 
                    replace = replace.substring(0,replace.lastIndexOf(".")+1)+className;
    
                    try {
                        Class<?> aClass = Class.forName(replace);
                        if (aClass != null) {
                            beanDefinition.setBeanClassName(replace);
                            ((ScannedGenericBeanDefinition) beanDefinition).setBeanClass(aClass);
                        }
                    } catch (ClassNotFoundException e) {
                        // do nothing
                    }
                }
            }
        }
    }

/**
     * ClassName: PrintService
     *
     * @Author: ME
     * Description: 标准bean
     */
    @Slf4j
    @Service
    public class PrintService {
    
        public void print(){
            log.info("use   default    bean");
        }
    }

/**
     * ClassName: PrintService
     *
     * @Author: ME
     * Description:个性化的bean
     */
    @Slf4j
    @Service
    public class ICBCPrintService extends PrintService {
    
        public void print(){
            log.info("use   icbc    bean");
        }
    }

/**
     * ClassName: PrintService
     *
     * @Author: ME
     * Description: 个性化的bean
     */
    @Slf4j
    @Service
    public class BOCPrintService extends PrintService {
    
        public void print(){
            log.info("use   boc    bean");
        }
    }

\# 程序入口，@ComponentScan配置默认不扫描个性化bean；

\# @PersonaliseComponentScan配置是否启用个性化扫描；

`# 个性化扫描路径为：PersonnalizeApplication包名` +`project`\+`application.yml配置名`, 如： com`.me.personalize.project.BOC`

\# 扫描到的个性化bean将会替换标准bean;

@SpringBootApplication
    @ComponentScan(
            excludeFilters = @ComponentScan.Filter(
                    type = FilterType.REGEX,
                    pattern = "com.me.personnalize.project.*"
            )
    )
    @PersonaliseComponentScan
    public class PersonnalizeApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(PersonnalizeApplication.class, args);
        }
    
    }

测试类：

@RunWith(SpringRunner.class)
    @SpringBootTest
    public class PersonnalizeApplicationTests {
        // 自动装配一个bean
        @Resource
        PrintService printService;
    
        @Test
        public void contextLoads() {
            printService.print();
        }
    
    }

# 3.效果 #

3.1 配置标准启动时

personalise:  
        projectName: default

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xpYW5nQ0pQ_size_16_color_FFFFFF_t_70 1][]

3.2 配置BOC个性化启动

personalise:  
        projectName: BOC

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xpYW5nQ0pQ_size_16_color_FFFFFF_t_70 2][]

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