Spring automatically assembles byName

Spring automatically byName

This pattern specifies automatic assembly by the property name. T he Spring container is considered beans, and the auto-wire property of beans in the XML profile is set to byName. I t then tries to match and connect its properties to beans defined as the same name in the profile. If a match is found, it injects these beans, otherwise it throws an exception.

For example, in a configuration file, if a bean definition is set to automatically assemble byName, and it contains the spellChecker property (that is, it has a setSpellChecker(...) method), Spring looks for the bean that defines the definition named spellChecker and uses it to set that property. Y ou can still connect the rest of the properties using the .lt;property.gt; tag. The following example illustrates this concept.

Let's use the Eclipse IDE in the right place, and then follow these steps to create a Spring application:

Here is the contents of .java textEditor file:

package com.tutorialspoint;
public class TextEditor {
   private SpellChecker spellChecker;
   private String name;
   public void setSpellChecker( SpellChecker spellChecker ){
      this.spellChecker = spellChecker;
   }
   public SpellChecker getSpellChecker() {
      return spellChecker;
   }
   public void setName(String name) {
      this.name = name;
   }
   public String getName() {
      return name;
   }
   public void spellCheck() {
      spellChecker.checkSpelling();
   }
}

Here's what's in another class-dependent .java SpellChecker:

package com.tutorialspoint;
public class SpellChecker {
   public SpellChecker() {
      System.out.println("Inside SpellChecker constructor." );
   }
   public void checkSpelling() {
      System.out.println("Inside checkSpelling." );
   }   
}

Here's what .java mainApp files are:

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");
      TextEditor te = (TextEditor) context.getBean("textEditor");
      te.spellCheck();
   }
}

Here is the profile Beans file .xml normal:

<?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">

   <!-- Definition for textEditor bean -->
   <bean id="textEditor" class="com.tutorialspoint.TextEditor">
       <property name="spellChecker" ref="spellChecker" />
       <property name="name" value="Generic Text Editor" />
   </bean>

   <!-- Definition for spellChecker bean -->
   <bean id="spellChecker" class="com.tutorialspoint.SpellChecker">
   </bean>

</beans>

However, if you want to use auto-assemble "byName", your XML profile will become as follows:

<?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">

   <!-- Definition for textEditor bean -->
   <bean id="textEditor" class="com.tutorialspoint.TextEditor" 
      autowire="byName">
      <property name="name" value="Generic Text Editor" />
   </bean>

   <!-- Definition for spellChecker bean -->
   <bean id="spellChecker" class="com.tutorialspoint.SpellChecker">
   </bean>

</beans>

Once you're done creating the source code and bean profile, we can run the application. If your application is all right, it will print the following message:

Inside SpellChecker constructor.
Inside checkSpelling.