Spring AutoWire

AutoWire 有 ByType ,ByName两种主要使用方式

public class Boss {
		@Autowired
	 	private Car car;   
	    public Car getCar() {
			return car;
		}
		public void setCar(Car car) {
			this.car = car;
		}
		public Office getOffice() {
			return office;
		}
		public void setOffice(Office office) {
			this.office = office;
		}
		@Autowired
		private Office office;   
	    //省略 get/setter   
		@Override
		public String toString() {
			return "Boss [car=" + car + ", office=" + office + "]";
		}
	    
}


public class Car {
	String brand;
	public String getBrand() {
		return brand;
	}
	public void setBrand(String brand) {
		this.brand = brand;
	}
	public String getPrice() {
		return price;
	}
	public void setPrice(String price) {
		this.price = price;
	}
	String price;
}
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		ApplicationContext ctx = new ClassPathXmlApplicationContext(
                "applicationContext.xml");
		Boss boss = (Boss) ctx.getBean("boss");   
        System.out.println(boss);  
	}

}
public class Office {
	private String officeNo;

	public String getOfficeNo() {
		return officeNo;
	}

	public void setOfficeNo(String officeNo) {
		this.officeNo = officeNo;
	}
}

　　

<?xml version="1.0" encoding="UTF-8" ?>   
<beans xmlns="http://www.springframework.org/schema/beans"  
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
    xsi:schemaLocation="http://www.springframework.org/schema/beans    
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">   
    <bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>   

    <bean id="boss" class="Boss">   
       
    </bean>   
    <bean id="office1" class="Office">   
        <property name="officeNo" value="002"/>   
    </bean>   
    <bean id="office2" class="Office">   
        <property name="officeNo" value="003"/>   
    </bean>   
    <bean id="car" class="Car" scope="singleton">   
        <property name="brand" value="hongqi"/>   
        <property name="price" value="200000"/>   
    </bean>   
</beans>

　　上面这种写法会报异常，因为有多个Office类型，又没有同名id.

<?xml version="1.0" encoding="UTF-8" ?>   
<beans xmlns="http://www.springframework.org/schema/beans"  
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
    xsi:schemaLocation="http://www.springframework.org/schema/beans    
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">   
    <bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>   

    <bean id="boss" class="Boss">   
       
    </bean>   
    <bean id="office" class="Office">   
        <property name="officeNo" value="002"/>   
    </bean>   
    <bean id="office2" class="Office">   
        <property name="officeNo" value="003"/>   
    </bean>   
    <bean id="car" class="Car" scope="singleton">   
        <property name="brand" value="红旗CA72"/>   
        <property name="price" value="2000"/>   
    </bean>   
</beans>

　　这种写法会选择id="office".