03-Scope注解

@Scope设置组件作用域

总结

• singleton: ioc容器创建的时候调用bean方法创建bean对象
• prototype: 每次bean对象被调用的时候创建
• 使用 @Lazy 可以使得bean对象在被调用的时候才加载

验证

prototype模式

package com.xiong.config;

import com.xiong.bean.Person;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

@Configuration
public class PersonConfig {

    @Scope(value = BeanDefinition.SCOPE_PROTOTYPE)
    @Bean
    Person person() {
        System.out.println("为ioc容器添加person对象");
        Person person = new Person();
        person.setName("person");
        person.setAge(20);
        return person;
    }
}

package com.xiong;


import com.xiong.bean.Person;
import com.xiong.config.PersonConfig;
import com.xiong.service.PersonService;
import org.junit.jupiter.api.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainTest {
    @Test
    public void prototypeTest() {
        ApplicationContext context = new AnnotationConfigApplicationContext(PersonConfig.class);
        System.out.println("====================bean对象调用后=======================");
        Person personA = context.getBean(Person.class);
        Person personB = context.getBean(Person.class);
        System.out.println(personA == personB);
    }
}

singleton模式

package com.xiong.config;

import com.xiong.bean.Person;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

@Configuration
public class PersonConfig {

    @Scope(value = BeanDefinition.SCOPE_SINGLETON)
    @Bean
    Person person() {
        System.out.println("为ioc容器添加person对象");
        Person person = new Person();
        person.setName("person");
        person.setAge(20);
        return person;
    }
}

package com.xiong;


import com.xiong.bean.Person;
import com.xiong.config.PersonConfig;
import com.xiong.service.PersonService;
import org.junit.jupiter.api.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainTest {
    @Test
    public void singletonTest(){
        ApplicationContext context = new AnnotationConfigApplicationContext(PersonConfig.class);
        System.out.println("====================bean对象调用前后=======================");
        Person personA = context.getBean(Person.class);
        Person personB = context.getBean(Person.class);
        System.out.println(personA == personB);
    }
}

@Lazy注解

package com.xiong.config;

import com.xiong.bean.Person;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

@Configuration
public class PersonConfig {

    @Lazy
    @Scope(value = BeanDefinition.SCOPE_SINGLETON)
    @Bean
    Person person() {
        System.out.println("为ioc容器添加person对象");
        Person person = new Person();
        person.setName("person");
        person.setAge(20);
        return person;
    }
}

package com.xiong;


import com.xiong.bean.Person;
import com.xiong.config.PersonConfig;
import com.xiong.service.PersonService;
import org.junit.jupiter.api.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainTest {
    @Test
    public void singletonTest(){
        ApplicationContext context = new AnnotationConfigApplicationContext(PersonConfig.class);
        System.out.println("====================bean对象调用前后=======================");
        Person personA = context.getBean(Person.class);
        Person personB = context.getBean(Person.class);
        System.out.println(personA == personB);
    }
}