3、Spring注解开发，第三天

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第三天：Spring annotation开发

目录：1、@Import给容器快速导入一个组件 2、@Import使用importSelector注册组件 3、@Import使用importBeanDefinitionRegistrar注册组件 4、使用BeanFactory注册组件

一、@Import给容器中快速导入一个组件

回忆给容器中注入组件的方式：
1、包扫描+组件标注注解[@Controller @Service @Repository @Component]---自己写的类
2、@Bean--导入第三方包里面的组件--[在方法上method]
3、@Import----[在类上]
	3.1)、@Import(要导入的组件)，容器中就会自动注册这个组件，ID默认是全类名
    3.2)、ImportSelector:[implements ImportSelector]返回需要导入的组件的全类名数组
	3.3)、ImportBeanDefinitionRegistrar：[implements ImportBeanDefinitionRegistrar] 返回需要导入的组件的全类名数组
4、使用Spring提供的FactoryBean(工厂Bean)
	4.1)、默认获取到的是工厂Bean调用getObject创建的对象
	4.2)、要获取工厂bean本身，我们需要给ID钱面加一个&符

Color.class

package com.lee.bean;

public class Color {

}

Red.class

package com.lee.bean;

public class Red {

}

MainTest.class

    @Test
    public void testImport(){
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfig2.class);
        String[] names = context.getBeanDefinitionNames();
        for(String name : names){
            System.out.println("-->"+name);
        }
    }

结果：

-->mainConfig2
-->mainConfig
-->bookController
-->bookDao
-->bookService
-->person
-->bill

给MainConfig.class添加注解

@ComponentScan(value = "com.lee")//包扫描
@Configuration//这是个配置类
@Import({Color.class, Red.class})//给容器注册组件--id默认是全类名
public class MainConfig2 {

//    @Lazy//懒加载
//    @Scope(value = "prototype")
    @Bean
    public Person person(){
        return new Person(1,"张三","male");
    }


    @Conditional({WindowsCondition.class})
    @Bean("bill")
    public Person person01(){
        return new Person(2,"bill Gates","male");
    }

    @Conditional(LinuxCondition.class)
    @Bean("linus")
    public Person person02(){
        return new Person(3,"linus","male");
    }
}

结果：

-->mainConfig2
-->mainConfig
-->bookController
-->bookDao
-->bookService
-->person
-->com.lee.bean.Color
-->com.lee.bean.Red
-->bill

二、@Import使用ImportSelector注册组件

Blue.class

package com.lee.bean;

public class Blue {

}

Yellow.class

package com.lee.bean;

public class Yello {

}

MyImportSelector.class

package com.lee.conditions;

import org.springframework.context.annotation.ImportSelector;
import org.springframework.core.type.AnnotationMetadata;

public class MyImportSelector implements ImportSelector {


    /**
     * 返回值，就是导入到容器中的组件的全类名
     * AnnotationMetadata：当前标注@Import注解类的所有注解信息-MainConfig2
     */
    @Override
    public String[] selectImports(AnnotationMetadata importingClassMetadata) {
        return new String[]{"com.lee.bean.Blue","com.lee.bean.Yello"};
    }

}

MainConfig2.class

package com.lee.config;

import com.lee.bean.Color;
import com.lee.bean.Person;
import com.lee.bean.Red;
import com.lee.conditions.LinuxCondition;
import com.lee.conditions.MyImportSelector;
import com.lee.conditions.WindowsCondition;
import org.springframework.context.annotation.*;

@ComponentScan(value = "com.lee")//包扫描
@Configuration//这是个配置类
@Import({Color.class, Red.class, MyImportSelector.class})//给容器注册组件--id默认是全类名
public class MainConfig2 {

//    @Lazy//懒加载
//    @Scope(value = "prototype")
    @Bean
    public Person person(){
        return new Person(1,"张三","male");
    }


    @Conditional({WindowsCondition.class})
    @Bean("bill")
    public Person person01(){
        return new Person(2,"bill Gates","male");
    }

    @Conditional(LinuxCondition.class)
    @Bean("linus")
    public Person person02(){
        return new Person(3,"linus","male");
    }
}

MainTest.class

    @Test
    public void testImportSelector(){
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfig2.class);
        String[] names = context.getBeanDefinitionNames();
        for(String name : names){
            System.out.println("-->"+name);
        }
    }

结果：

-->mainConfig2
-->mainConfig
-->bookController
-->bookDao
-->bookService
-->person
-->com.lee.bean.Color
-->com.lee.bean.Red
-->com.lee.bean.Blue
-->com.lee.bean.Yello
-->bill

三、@Import使用ImportBeanDefinitionRegistrar

RainBow.class

package com.lee.bean;

public class RainBow {

}

MyImportBeanDefinitionRegistrar.class

package com.lee.conditions;

import com.lee.bean.RainBow;
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;

public class MyImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {


    /**
     * AnnotationMetadata: 添加@Import类的所有注解信息
     * BeanDefinitionRegistry：BeanDefinition注册类
     *      把所有需要添加到容器中的bean：调用
     *          registry.registerBeanDefinition手工注册进来
     */
    @Override
    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {

        boolean isRed = registry.containsBeanDefinition("com.lee.bean.Red");//是否包含红色
        boolean isBlue = registry.containsBeanDefinition("com.lee.bean.Blue");//是否包含蓝色
        if(isRed && isBlue){
            //指定 bean的信息，（bean的类型Rainbow.class）
            RootBeanDefinition definition = new RootBeanDefinition(RainBow.class);
            //注册一个bean，指定bean名
            registry.registerBeanDefinition("rainBow",definition);
        }

    }
}

MainConfig2.class

package com.lee.config;

import com.lee.bean.Color;
import com.lee.bean.Person;
import com.lee.bean.Red;
import com.lee.conditions.LinuxCondition;
import com.lee.conditions.MyImportBeanDefinitionRegistrar;
import com.lee.conditions.MyImportSelector;
import com.lee.conditions.WindowsCondition;
import org.springframework.context.annotation.*;

@ComponentScan(value = "com.lee")//包扫描
@Configuration//这是个配置类
@Import({Color.class, Red.class, MyImportSelector.class, MyImportBeanDefinitionRegistrar.class})//给容器注册组件--id默认是全类名
public class MainConfig2 {

//    @Lazy//懒加载
//    @Scope(value = "prototype")
    @Bean
    public Person person(){
        return new Person(1,"张三","male");
    }


    @Conditional({WindowsCondition.class})
    @Bean("bill")
    public Person person01(){
        return new Person(2,"bill Gates","male");
    }

    @Conditional(LinuxCondition.class)
    @Bean("linus")
    public Person person02(){
        return new Person(3,"linus","male");
    }
}

结果：

-->mainConfig2
-->mainConfig
-->bookController
-->bookDao
-->bookService
-->person
-->com.lee.bean.Color
-->com.lee.bean.Red
-->com.lee.bean.Blue
-->com.lee.bean.Yello
-->bill
-->rainBow

四、使用FactoryBean注册组件

ColorFactoryBean.class

package com.lee.bean;

import org.springframework.beans.factory.FactoryBean;

public class ColorFactoryBean implements FactoryBean<Color> {

    //返回的类
    @Override
    public Color getObject() throws Exception {
        return new Color();
    }

    //返回类的类型
    @Override
    public Class<?> getObjectType() {
        return Color.class;
    }

    //是否单例
    @Override
    public boolean isSingleton() {
        return true;
    }
}

MainConfig2.class

package com.lee.config;

import com.lee.bean.Color;
import com.lee.bean.ColorFactoryBean;
import com.lee.bean.Person;
import com.lee.bean.Red;
import com.lee.conditions.LinuxCondition;
import com.lee.conditions.MyImportBeanDefinitionRegistrar;
import com.lee.conditions.MyImportSelector;
import com.lee.conditions.WindowsCondition;
import org.springframework.context.annotation.*;

@ComponentScan(value = "com.lee")//包扫描
@Configuration//这是个配置类
@Import({Color.class, Red.class, MyImportSelector.class, MyImportBeanDefinitionRegistrar.class})//给容器注册组件--id默认是全类名
public class MainConfig2 {


    @Bean
    public ColorFactoryBean colorFactoryBean(){
        return new ColorFactoryBean();
    }

//    @Lazy//懒加载
//    @Scope(value = "prototype")
    @Bean
    public Person person(){
        return new Person(1,"张三","male");
    }


    @Conditional({WindowsCondition.class})
    @Bean("bill")
    public Person person01(){
        return new Person(2,"bill Gates","male");
    }

    @Conditional(LinuxCondition.class)
    @Bean("linus")
    public Person person02(){
        return new Person(3,"linus","male");
    }
}

MainTest.class

    @Test
    public void  testFactoryBean(){
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfig2.class);
        String[] names = context.getBeanDefinitionNames();
        for(String name : names){
            System.out.println("-->"+name);
        }
        Object colorFactoryBean1 = context.getBean("colorFactoryBean");
        System.out.println("bean的类型1:"+colorFactoryBean1.getClass());
        Object colorFactoryBean2 = context.getBean("colorFactoryBean");
        System.out.println(colorFactoryBean1 == colorFactoryBean2);

        Object bean = context.getBean("&colorFactoryBean");
        System.out.println("bean的类型2:"+bean.getClass());

    }

结果：

-->mainConfig2
-->mainConfig
-->bookController
-->bookDao
-->bookService
-->person
-->com.lee.bean.Color
-->com.lee.bean.Red
-->com.lee.bean.Blue
-->com.lee.bean.Yello
-->colorFactoryBean
-->bill
-->rainBow
bean的类型1:class com.lee.bean.Color
true
bean的类型2:class com.lee.bean.ColorFactoryBean