【Spring】使用注解装配bean
目录
使用注解的两个必要步骤
正文
Cat
Dog
Animal
beans.xml
测试
@Qualifier
使用注解的两个必要步骤
1.导入约束
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns=""xmlns:xsi=""xmlns:context=""xsi:schemaLocation=" ://www.springframework/schema/beans/spring-beans.xsd://www.springframework/schema/context/spring-context.xsd"></beans>
2.配置注解的支持
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns=""xmlns:xsi=""xmlns:context=""xsi:schemaLocation=" ://www.springframework/schema/beans/spring-beans.xsd://www.springframework/schema/context/spring-context.xsd"><context:annotation-config/>
</beans>
<context:annotation-config/> //配置注解的支持
正文
Cat
package org.example;public class Cat {public void eat(){System.out.println("猫吃鱼干");}
}
Dog
package org.example;public class Dog {public void sleep(){System.out.println("小狗睡大觉");}
}
Animal
package org.example;import org.springframework.beans.factory.annotation.Autowired;public class Animal {@Autowiredprivate Cat cat;@Autowiredprivate Dog dog;public Cat getCat() {return cat;}public void setCat(Cat cat) {this.cat = cat;}public Dog getDog() {return dog;}public void setDog(Dog dog) {this.dog = dog;}@Overridepublic String toString() {return "Animal{" +"cat=" + cat +", dog=" + dog +'}';}
}
注意：要加上自动装配注解
set方法可以去掉也可以不用去掉
去掉的话如下图
package org.example;import org.springframework.beans.factory.annotation.Autowired;public class Animal {@Autowiredprivate Cat cat;@Autowiredprivate Dog dog;public Cat getCat() {return cat;}public Dog getDog() {return dog;}@Overridepublic String toString() {return "Animal{" +"cat=" + cat +", dog=" + dog +'}';}
}
beans.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns=""xmlns:xsi=""xmlns:context=""xsi:schemaLocation=" ://www.springframework/schema/beans/spring-beans.xsd://www.springframework/schema/context/spring-context.xsd"><context:annotation-config/><bean id="cat" class="org.example.Cat" /><bean id="dog" class="org.example.Dog" /><bean id="animal" class="org.example.Animal" /></beans>测试
package org.example;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Test9 {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");Animal animal=(Animal) context.getBean("animal");animal.getCat().eat();animal.getDog().sleep();}
}
@Qualifier
与注解@Autowired配合使用
<bean id="cat111" class="org.example.Cat" /> <bean id="cat222" class="org.example.Cat" /> <bean id="cat333" class="org.example.Cat" />如果有多个关于cat的bean的话，使用@Qualifier可以显式指定哪一个bean注入，
【Spring】使用注解装配bean
目录
使用注解的两个必要步骤
正文
Cat
Dog
Animal
beans.xml
测试
@Qualifier
使用注解的两个必要步骤
1.导入约束
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns=""xmlns:xsi=""xmlns:context=""xsi:schemaLocation=" ://www.springframework/schema/beans/spring-beans.xsd://www.springframework/schema/context/spring-context.xsd"></beans>
2.配置注解的支持
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns=""xmlns:xsi=""xmlns:context=""xsi:schemaLocation=" ://www.springframework/schema/beans/spring-beans.xsd://www.springframework/schema/context/spring-context.xsd"><context:annotation-config/>
</beans>
<context:annotation-config/> //配置注解的支持
正文
Cat
package org.example;public class Cat {public void eat(){System.out.println("猫吃鱼干");}
}
Dog
package org.example;public class Dog {public void sleep(){System.out.println("小狗睡大觉");}
}
Animal
package org.example;import org.springframework.beans.factory.annotation.Autowired;public class Animal {@Autowiredprivate Cat cat;@Autowiredprivate Dog dog;public Cat getCat() {return cat;}public void setCat(Cat cat) {this.cat = cat;}public Dog getDog() {return dog;}public void setDog(Dog dog) {this.dog = dog;}@Overridepublic String toString() {return "Animal{" +"cat=" + cat +", dog=" + dog +'}';}
}
注意：要加上自动装配注解
set方法可以去掉也可以不用去掉
去掉的话如下图
package org.example;import org.springframework.beans.factory.annotation.Autowired;public class Animal {@Autowiredprivate Cat cat;@Autowiredprivate Dog dog;public Cat getCat() {return cat;}public Dog getDog() {return dog;}@Overridepublic String toString() {return "Animal{" +"cat=" + cat +", dog=" + dog +'}';}
}
beans.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns=""xmlns:xsi=""xmlns:context=""xsi:schemaLocation=" ://www.springframework/schema/beans/spring-beans.xsd://www.springframework/schema/context/spring-context.xsd"><context:annotation-config/><bean id="cat" class="org.example.Cat" /><bean id="dog" class="org.example.Dog" /><bean id="animal" class="org.example.Animal" /></beans>测试
package org.example;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Test9 {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");Animal animal=(Animal) context.getBean("animal");animal.getCat().eat();animal.getDog().sleep();}
}
@Qualifier
与注解@Autowired配合使用
<bean id="cat111" class="org.example.Cat" /> <bean id="cat222" class="org.example.Cat" /> <bean id="cat333" class="org.example.Cat" />如果有多个关于cat的bean的话，使用@Qualifier可以显式指定哪一个bean注入，