spring 中常用的組件標(biāo)簽有：

@Controller：控制層

@Service：業(yè)務(wù)層

@Repository：數(shù)據(jù)層

@Component:普通的pojo注入到spring容器

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組件注冊方式：

?@ComponentScan? 掃描那些要注入到spring容器的組件的包路徑

package com.annotation.component;
import org.springframework.stereotype.Controller;
import org.springframework.context.annotation.Configuration;@Controller
public class PersonController {}package com.annotation.register;
import org.springframework.context.annotation.ComponentScan;//表明這是個(gè)注解配置類
@Configuration  
@ComponentScan(value={"com.annotation.component"})
public class  Config {}package com.annotation.register;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import com.annotation.component.controller.PersonController;public class Test {public static void main(String[] args) {   AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext(Config.class);PersonController personController = annotationConfigApplicationContext.getBean(PersonController.class);}
}

?@bean :主要作用在方法上，name可以指定bean在容器中的名稱，不指定的話默認(rèn)是方法名；initMethod指定bean的初始化方法；destroyMethod指定bean的銷毀方法

package com.annotation.component;public class Blue {}package com.annotation.register;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.annotation.component.bean.Blue;@Configuration  
public class MainConfig {@Bean(name="blue")public Blue getColor(){return new Blue();}}package com.annotation.register;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;import com.annotation.component.bean.Blue;public class Test {public static void main(String[] args) {AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext(MainConfig.class);Blue blue= annotationConfigApplicationContext.getBean(Blue.class);System.out.println(blue);}
}

?@Import? ?:

• 注入一個(gè)bean
• 導(dǎo)入ImportSelector的實(shí)現(xiàn)類，selectImports方法里面配置要注入的bean
• 導(dǎo)入ImportBeanDefinitionRegistrar的實(shí)現(xiàn)類，registerBeanDefinitions方法里面配置要注入的bean

? ? ? ? ? ??

package com.annotation.component.bean;public class Blue {}package com.annotation.component.bean;public class Yellow {}package com.annotation.component.bean;public class Green{}package com.annotation.importbean;import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import com.annotation.component.bean.White;@Configuration  
@Import(value = { White.class,MyImportSelector.class,MyImportBeanDefinitionRegistrar.class })
public class MainConfig {}package com.annotation.importbean;import org.springframework.context.annotation.ImportSelector;
import org.springframework.core.type.AnnotationMetadata;public class MyImportSelector implements ImportSelector{@Overridepublic String[] selectImports(AnnotationMetadata annotationmetadata) {return new String[]{"com.annotation.component.bean.Yellow"};}}package com.annotation.importbean;import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.type.AnnotationMetadata;import com.annotation.component.bean.Green;public class MyImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar{@Overridepublic void registerBeanDefinitions(AnnotationMetadata annotationmetadata,BeanDefinitionRegistry beandefinitionregistry) {RootBeanDefinition beanDefinition = new RootBeanDefinition(Green.class);beandefinitionregistry.registerBeanDefinition("com.annotation.component.bean.Green", beanDefinition);}}package com.annotation.importbean;import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class Test {public static void main(String[] args) {    AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext(MainConfig.class);String[] names = annotationConfigApplicationContext.getBeanDefinitionNames();for (String name : names) {System.out.println(name);}annotationConfigApplicationContext.close();}
}

?implements FactoryBean

• getObject 方法表示要注入的對象，getObjectType表示對象類型，isSingleton表示是否單例
• annotationConfigApplicationContext.getBean("colorFactoryBean") 表示獲取的是工程里面注入的對象，即Color
• annotationConfigApplicationContext.getBean("&colorFactoryBean") 表示獲取的是工程對象本身，即ColorFactoryBean

package com.annotation.component.bean;public class Color {}package com.annotation.factorybean;import org.springframework.beans.factory.FactoryBean;import com.annotation.component.bean.Color;public class ColorFactoryBean implements FactoryBean<Color>{@Overridepublic Color getObject() throws Exception {return new Color();}@Overridepublic Class<?> getObjectType() {return Color.class;}@Overridepublic boolean isSingleton() {return false;}}package com.annotation.factorybean;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration  
public class MainConfig {@Beanpublic ColorFactoryBean colorFactoryBean(){return new ColorFactoryBean();}}package com.annotation.factorybean;import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class Test {public static void main(String[] args) {AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext(MainConfig.class);Object obj1 = annotationConfigApplicationContext.getBean("colorFactoryBean");Object obj2 = annotationConfigApplicationContext.getBean("colorFactoryBean");
        System.out.println(obj1==obj2);//獲取factorybean 本身Object obj3 = annotationConfigApplicationContext.getBean("&colorFactoryBean");System.out.println(obj3.getClass());annotationConfigApplicationContext.close();}
}

?

轉(zhuǎn)載于:https://www.cnblogs.com/chenzhubing/p/11010745.html

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