Back to: Spring Framework Tutorials

Spring Framework Autowiring by Name

In this article, I am going to discuss Spring Framework Autowiring by Name with Examples. Please read our previous article, where we discussed Spring Framework Autowiring.

What is Autowiring by Name in Spring Framework?

As we learned already, Autowiring by name in Spring is a type of Autowiring that matches beans based on their names. When Autowiring by name is enabled, Spring looks for beans in the application context with the same name as the dependency being injected and automatically wires them together.

Autowiring by name can be useful when you want to specify a particular bean by its name to be injected, especially in scenarios where multiple beans of the same type exist in the application context. It provides a way to disambiguate and explicitly control the wiring based on bean names.

However, Autowiring by name has a limitation in that the bean names must match exactly with the dependency names. Any mismatch in names will result in an exception. It also introduces tight coupling between the bean and the dependency name, making it less flexible and harder to refactor or change the bean names without updating the wiring configuration.

Implementing Autowiring by Name in Spring Framework

Before starting the project, ensure that the required JAR files are in the project’s “Referenced Libraries” folder.

In this article, we will be building upon the project from the previous article (‘Spring Framework Setter Dependency Injection’). The files and their contents should be as follows:

Kettle.java

public class Kettle
{
    private Drink drink;

    public void pour()
    {System.out.println("Pouring " + drink.getName() + " into cups.");}

    public void setDrink(Drink drink)
    {
        System.out.println("Pouring drink into kettle: " + drink.getName());
        this.drink = drink;
    }
}

This class represents a POJO class which will be used to represent a kettle.

Drink.java

public class Drink
{
    private String name;

    public String getName() {
        return name;
    }

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

This class represents a POJO class which will be used to represent a drink. Note that the setters and getters can be automatically added using the “Source Action…” option in the right-click menu of VS Code.

App.java

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

public class App
{
    public static void main(String[] args)
    {
        ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");
        Kettle k = (Kettle) context.getBean("kettle");
        k.pour();
    }
}

The main function creates a student object and a grade object from the beans.xml file. It then prints out the objects to the terminal.

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"
   xsi:schemaLocation = "http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

   <bean id = "kettle" class = "Kettle" autowire = "byName"/>
   
   <bean id = "drink" class = "Drink">
     <property name = "name" value = "tea" />
   </bean>

</beans>

We have rewritten the statements such that the drink variable is Autowired by name.

Step 2: Compile and execute the application. Ensure compilation is successful. Ensure that the output is as expected:

Congratulations! You have completed the Autowiring by name application in Spring Framework!

Benefits of Autowiring by Name in Spring Framework:

• Simplicity and Convenience: Autowiring by name reduces the need for explicit wiring in the configuration files. It simplifies the configuration process by leveraging naming conventions, which can be convenient, especially for small to medium-sized projects.
• Readable Configuration: Autowiring by name improves the readability of the configuration files. Since the dependencies are not explicitly specified, the configuration files are less cluttered and easier to understand.
• Flexibility in Bean Renaming: Autowiring by name allows you to rename beans without requiring changes in the dependent beans. As long as the names of the properties or constructor parameters in the dependent beans match the new names, the Autowiring will continue to work seamlessly.

Limitations of Autowiring by Name in Spring Framework:

• Case Sensitivity: By default, Autowiring by name is case-sensitive. The names of the beans and the names of the properties or constructor parameters must match exactly. This can lead to potential issues if there are discrepancies in the case of the names.
• Lack of Explicitness: Autowiring by name reduces the explicitness of the dependencies. The dependencies are not clearly visible in the code, making it harder for developers to identify and understand them without referring to the configuration files.
• Limited Control: Autowiring by name provides less control over the wiring process compared to explicit wiring. Developers have to rely on naming conventions, which may not be sufficient in complex scenarios where more fine-grained control is required.
• Potential Naming Conflicts: Autowiring by name can introduce naming conflicts if multiple beans have similar or identical names. This can lead to ambiguity and unpredictable results. It is important to ensure unique and meaningful bean names to avoid such conflicts.

Autowiring by name in Spring offers simplicity and convenience by leveraging naming conventions for dependency injection. It reduces the configuration effort and enhances readability. However, it also has limitations in terms of case sensitivity, lack of explicitness, and potential naming conflicts. It is important to weigh the benefits and drawbacks and consider the specific requirements of your project before deciding to use Autowiring by name.

In the next article, I am going to discuss Spring Framework Autowiring by Type. Here, in this article, I try to explain Spring Framework Autowiring by Name with Examples. I hope you enjoy this Spring Framework Autowiring by Name article.