Spring @Qualifier Annotation

There may be a situation when you create more than one bean of the same type and want to wire only one of them with a property. In such cases, you can use the @Qualifier annotation along with @Autowired to remove the confusion by specifying which exact bean will be wired. Following is an example to show the use of @Qualifier annotation.

Example

Let us have a working Eclipse IDE in place and take the following steps to create a Spring application −

Here is the content of Student.java file −

package com.tutorialspoint;

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;
   }
}

Here is the content of Profile.java file

package com.tutorialspoint;

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() );
   }
}

Following is the content of the MainApp.java file.

package com.tutorialspoint;

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();
   }
}

Consider the example of following configuration file Beans.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-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.tutorialspoint.Profile"></bean>

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

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

</beans>

Once you are done creating the source and bean configuration files, let us run the application. If everything is fine with your application, it will print the following message −

Inside Profile constructor.
Age : 11
Name : Zara