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".