使用@Qualifier时，我仍然会遇到UnsatisfiedDependency异常，有人能帮我吗

Question

public class Car {
    @Qualifier("e2")
    @Autowired  
    private Engine engine;

    public void printData() {
        System.out.println("Engine object ref "+engine.getModelOfYear());
        }
}

public class Engine {

    private String modelOfYear;

    public String getModelOfYear() {
        return modelOfYear;
    }
    public void setModelOfYear(String modelOfYear) {
        this.modelOfYear = modelOfYear;
    }
}

spring.xml

<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN" "http://www.springframework.org/dtd/spring-beans-2.0.dtd">
<beans>
<bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>
    <bean id="e1" class="beans.Engine">
        <property name="modelOfYear" value="2013"/>
    </bean>
    <bean id="e2" class="beans.Engine">
        <property name="modelOfYear" value="2011"/>
    </bean>
    <bean id="c1" class="beans.Car"/>
</beans>

测试类

 public class Test {
        public static void main(String[] args) {
            ApplicationContext ap=new ClassPathXmlApplicationContext("resources/Spring.xml");
            Car c=(Car)ap.getBean("c1");
            c.printData();
        }
    }

Answer 1

要使Spring在XML声明的bean中处理@autowired注释，请将 添加到Spring.XML:

<?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/>

    <bean id="e1" class="beans.Engine">
        <property name="modelOfYear" value="2013"/>
    </bean>
    <bean id="e2" class="beans.Engine">
        <property name="modelOfYear" value="2011"/>
    </bean>
    <bean id="c1" class="beans.Car"/>
</beans>