【Spring】注解开发

使用注解须知：

1.导入约束

2.配置注解的支持

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

    <context:annotation-config/>
</beans>

注解实现自动装配:

package com.lixin.pojo;

public class Cat {
    public void shout(){
        System.out.println("喵喵！");
    }
}
------------------------------------------------------------
package com.lixin.pojo;

public class Dog {
    public void shout(){
        System.out.println("汪汪！");
    }
}

--------------------------------------------------------------
import org.springframework.beans.factory.annotation.Autowired;

public class People {
    @Autowired
    private Cat cat;
    @Autowired
    private Dog dog;
    private String name;

    public Cat getCat() {
        return cat;
    }
    public Dog getDog() {
        return dog;
    }
    public String getName() {
        return name;
    }
    @Override
    public String toString() {
        return "People{" +
                "cat=" + cat +
                ", dog=" + dog +
                ", name='" + name + '\'' +
                '}';
    }
}

-------------------------------------------------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/aop
        http://www.springframework.org/schema/aop/spring-aop.xsd">

        <bean id="cra" class="com.lixin.pojo.Cat"/>
        <bean id="dog" class="com.lixin.pojo.Dog"/>
        <bean id="people" class="com.lixin.pojo.People"/>
    <context:annotation-config/>
</beans>

-----------------------------------------------------------------------------
import com.lixin.pojo.People;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context=new ClassPathXmlApplicationContext
                ("ApplicationContext.xml");
        People people=context.getBean("people",People.class);
        people.getDog().shout();
        people.getCat().shout();
    }
}

@Autowired
直接在属性上使用即可！也可以在set上使用
使用Autowired我们可以不用编写set方法，前提是这个自动装配的属性在IOC容器中存在且符合名字byName!