Springboot自動(dòng)裝配實(shí)現(xiàn)過(guò)程代碼實(shí)例
創(chuàng)建一個(gè)簡(jiǎn)單的項(xiàng)目:
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <artifactId>spring-boot-starter-parent</artifactId> <groupId>org.springframework.boot</groupId> <version>2.1.12.RELEASE</version> </parent> <groupId>com.xiazhi</groupId> <artifactId>demo</artifactId> <version>1.0-SNAPSHOT</version> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> </dependency> </dependencies> </project>
首先創(chuàng)建自定義注解:
package com.xiazhi.demo.annotation; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; /** * MyComponent 作用于類上,表示這是一個(gè)組件,于component,service注解作用相同 * @author zhaoshuai */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) public @interface MyComponent { }
package com.xiazhi.demo.annotation; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; /** * 作用于字段上,自動(dòng)裝配的注解,與autowired注解作用相同 * @author zhaoshuai */ @Target(ElementType.FIELD) @Retention(RetentionPolicy.RUNTIME) public @interface Reference { }
然后寫配置類:
package com.xiazhi.demo.config; import com.xiazhi.demo.annotation.MyComponent; import org.springframework.beans.factory.support.BeanDefinitionRegistry; import org.springframework.context.ResourceLoaderAware; import org.springframework.context.annotation.ClassPathBeanDefinitionScanner; import org.springframework.context.annotation.ImportBeanDefinitionRegistrar; import org.springframework.core.io.ResourceLoader; import org.springframework.core.type.AnnotationMetadata; import org.springframework.core.type.filter.AnnotationTypeFilter; /** * @author ZhaoShuai * @company lihfinance.com * @date Create in 2020/3/21 **/ public class ComponentAutoConfiguration implements ImportBeanDefinitionRegistrar, ResourceLoaderAware { private ResourceLoader resourceLoader; @Override public void registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry beanDefinitionRegistry) { String className = annotationMetadata.getClassName(); String basePackages = className.substring(0, className.lastIndexOf(".")); ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(beanDefinitionRegistry, false); scanner.addIncludeFilter(new AnnotationTypeFilter(MyComponent.class)); scanner.scan(basePackages); scanner.setResourceLoader(resourceLoader); } @Override public void setResourceLoader(ResourceLoader resourceLoader) { this.resourceLoader = resourceLoader; } }
上面是配置掃描指定包下被MyComponent注解標(biāo)注的類并注冊(cè)為spring的bean,bean注冊(cè)成功后,下面就是屬性的注入了
package com.xiazhi.demo.config; import com.xiazhi.demo.annotation.MyComponent; import com.xiazhi.demo.annotation.Reference; import org.springframework.beans.BeansException; import org.springframework.beans.factory.config.BeanPostProcessor; import org.springframework.boot.SpringBootConfiguration; import org.springframework.context.ApplicationContext; import org.springframework.context.ApplicationContextAware; import org.springframework.context.annotation.Bean; import org.springframework.util.ReflectionUtils; import java.lang.reflect.Field; /** * @author ZhaoShuai * @company lihfinance.com * @date Create in 2020/3/21 **/ @SpringBootConfiguration public class Configuration implements ApplicationContextAware { private ApplicationContext applicationContext; @Bean public BeanPostProcessor beanPostProcessor() { return new BeanPostProcessor() { /** * @company lihfinance.com * @author create by ZhaoShuai in 2020/3/21 * 在bean注冊(cè)前會(huì)被調(diào)用 * @param [bean, beanName] * @return java.lang.Object **/ @Override public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { return bean; } /** * @company lihfinance.com * @author create by ZhaoShuai in 2020/3/21 * 在bean注冊(cè)后會(huì)被加載,本次在bean注冊(cè)成功后注入屬性值 * @param [bean, beanName] * @return java.lang.Object **/ @Override public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { Class<?> clazz = bean.getClass(); if (!clazz.isAnnotationPresent(MyComponent.class)) { return bean; } Field[] fields = clazz.getDeclaredFields(); for (Field field : fields) { if (!field.isAnnotationPresent(Reference.class)) { continue; } Class<?> type = field.getType(); Object obj = applicationContext.getBean(type); ReflectionUtils.makeAccessible(field); ReflectionUtils.setField(field, bean, obj); } return bean; } }; } @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { this.applicationContext = applicationContext; } }
下面開(kāi)始使用注解來(lái)看看效果:
package com.xiazhi.demo.service; import com.xiazhi.demo.annotation.MyComponent; import javax.annotation.PostConstruct; /** * @author ZhaoShuai * @company lihfinance.com * @date Create in 2020/3/21 **/ @MyComponent public class MyService { @PostConstruct public void init() { System.out.println("hello world"); } public void test() { System.out.println("測(cè)試案例"); } }
package com.xiazhi.demo.service; import com.xiazhi.demo.annotation.MyComponent; import com.xiazhi.demo.annotation.Reference; /** * @author ZhaoShuai * @company lihfinance.com * @date Create in 2020/3/21 **/ @MyComponent public class MyConsumer { @Reference private MyService myService; public void aaa() { myService.test(); } }
啟動(dòng)類要引入配置文件:
import注解引入配置文件。
編寫測(cè)試類測(cè)試:
@SpringBootTest(classes = ApplicationRun.class) @RunWith(SpringRunner.class) public class TestDemo { @Autowired public MyConsumer myConsumer; @Test public void fun1() { myConsumer.aaa(); } }
以上就是本文的全部?jī)?nèi)容,希望對(duì)大家的學(xué)習(xí)有所幫助,也希望大家多多支持腳本之家。
相關(guān)文章
Java設(shè)計(jì)模式之監(jiān)聽(tīng)器模式實(shí)例詳解
這篇文章主要介紹了Java設(shè)計(jì)模式之監(jiān)聽(tīng)器模式,結(jié)合實(shí)例形式較為詳細(xì)的分析了java設(shè)計(jì)模式中監(jiān)聽(tīng)器模式的概念、原理及相關(guān)實(shí)現(xiàn)與使用技巧,需要的朋友可以參考下2018-02-02Java如何使用poi導(dǎo)入導(dǎo)出excel工具類
這篇文章主要介紹了Java如何使用poi導(dǎo)入導(dǎo)出excel工具類問(wèn)題,具有很好的參考價(jià)值,希望對(duì)大家有所幫助,如有錯(cuò)誤或未考慮完全的地方,望不吝賜教2024-06-06SWT(JFace)體驗(yàn)之Slider,Scale
SWT(JFace)體驗(yàn)之Slider,Scale實(shí)現(xiàn)代碼。2009-06-06Java經(jīng)典排序算法之快速排序代碼實(shí)例
這篇文章主要介紹了Java經(jīng)典排序算法之快速排序代碼實(shí)例,快速排序?qū)崿F(xiàn)的思想是指通過(guò)一趟排序?qū)⒁判虻臄?shù)據(jù)分割成獨(dú)立的兩部分,其中一部分的所有數(shù)據(jù)都比另外一部分的所有數(shù)據(jù)都要小,然后再按此方法對(duì)這兩部分?jǐn)?shù)據(jù)分別進(jìn)行快速排序,需要的朋友可以參考下2023-10-10