有可能是当你创建同一类型的多个bean，并希望连线只与属性其中之一，在这种情况下，你可以使用@Qualifier注解一起@Autowired的通过指定其确切的bean来去除混乱的局面将有线。下面是一个例子，说明使用@ Qualifier注解。

例子:

让我们使用Eclipse IDE，然后按照下面的步骤来创建一个Spring应用程序：

步骤	描述
1	Create a project with a name SpringExample and create a package com.yiibai under the src folder in the created project.
2	Add required Spring libraries using Add External JARs option as explained in the Spring Hello World Example chapter.
3	Create Java classes Student, Profile and MainApp under the com.yiibai package.
4	Create Beans configuration file Beans.xml under the src folder.
5	The final step is to create the content of all the Java files and Bean Configuration file and run the application as explained below.

这里是Student.java文件的内容：

package com.yiibai;

public class Student {
   private Integer age;
   private String name;

   public void setAge(Integer age) {
      this.age = age;
   }
   public Integer getAge() {
      return age;
   }

   public void setName(String name) {
      this.name = name;
   }
   public String getName() {
      return name;
   }
}

这里是Profile.java文件的内容：

package com.yiibai;

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

public class Profile {
   @Autowired
   @Qualifier("student1")
   private Student student;

   public Profile(){
      System.out.println("Inside Profile constructor." );
   }

   public void printAge() {
      System.out.println("Age : " + student.getAge() );
   }

   public void printName() {
      System.out.println("Name : " + student.getName() );
   }
}

以下是MainApp.java文件的内容：

package com.yiibai;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainApp {
   public static void main(String[] args) {
      ApplicationContext context = 
             new ClassPathXmlApplicationContext("Beans.xml");

      Profile profile = (Profile) context.getBean("profile");

      profile.printAge();
      profile.printName();
   }
}

请考虑下面的配置文件beans.xml中的例子：

<?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-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd">

   <context:annotation-config/>

   <!-- Definition for profile bean -->
   <bean id="profile" class="com.yiibai.Profile">
   </bean>

   <!-- Definition for student1 bean -->
   <bean id="student1" class="com.yiibai.Student">
      <property name="name"  value="Zara" />
      <property name="age"  value="11"/>
   </bean>

   <!-- Definition for student2 bean -->
   <bean id="student2" class="com.yiibai.Student">
      <property name="name"  value="Nuha" />
      <property name="age"  value="2"/>
   </bean>

</beans>

创建源代码和bean配置文件完成后，让我们运行应用程序。如果一切顺利，这将打印以下信息：

Inside Profile constructor.
Age : 11
Name : Zara

纠错/补充 收藏