- Spring DI Tutorial
- Spring DI - Home
- Spring DI - Overview
- Spring DI - Environment Setup
- Spring DI - IOC Containers
- Spring Dependency Injection
- Spring DI - Create Project
- Constructor Based Injection Examples
- Spring DI - Constructor Based
- Spring DI - Inner Beans Constructor
- Spring DI - Collections Constructor
- Spring DI - Collection Ref Constructor
- Spring DI - Map Constructor
- Spring DI - Map Ref Constructor
- Setter Based Injection Examples
- Spring DI - Setter Based
- Spring DI - Inner Beans Setter
- Spring DI - Collections Setter
- Spring DI - Collection Ref Setter
- Spring DI - Map Setter
- Spring DI - Map Ref Setter
- Autowiring Examples
- Spring DI - Autowiring
- Spring DI - Autowiring ByName
- Spring DI - Autowiring ByType
- Spring DI - Autowiring Constructor
- Factory Method
- Spring DI - Static Factory
- Spring DI - Non-Static Factory
- Spring DI Useful Resources
- Spring DI - Quick Guide
- Spring DI - Useful Resources
- Spring DI - Discussion
Spring DI - BeanFactory Container
This is the simplest container providing the basic support for DI and defined by the org.springframework.beans.factory.BeanFactory interface. The BeanFactory and related interfaces, such as BeanFactoryAware, InitializingBean, DisposableBean, are still present in Spring for the purpose of backward compatibility with a large number of third-party frameworks that integrate with Spring.
There are a number of implementations of the BeanFactory interface that are come straight out-of-the-box with Spring. The most commonly used BeanFactory implementation is the XmlBeanFactory class. This container reads the configuration metadata from an XML file and uses it to create a fully configured system or application.
The BeanFactory is usually preferred where the resources are limited like mobile devices or applet-based applications. Thus, use an ApplicationContext unless you have a good reason for not doing so.
Example
Let's update the project created in Spring DI - Create Project chapter. We're adding following files −
HelloWorld.java − A dependency class.
MainApp.java − Main application to run and test.
Here is the content of HelloWorld.java file −
package com.tutorialspoint; public class HelloWorld { private String message; public void setMessage(String message){ this.message = message; } public void getMessage(){ System.out.println("Your Message : " + message); } }
Following is the content of the second file MainApp.java
package com.tutorialspoint; import org.springframework.beans.factory.InitializingBean; import org.springframework.beans.factory.xml.XmlBeanFactory; import org.springframework.core.io.ClassPathResource; public class MainApp { public static void main(String[] args) { XmlBeanFactory factory = new XmlBeanFactory (new ClassPathResource("Beans.xml")); HelloWorld obj = (HelloWorld) factory.getBean("helloWorld"); obj.getMessage(); } }
Following two important points should be noted about the main program −
The first step is to create a factory object where we used the framework APIXmlBeanFactory() to create the factory bean andClassPathResource() API to load the bean configuration file available in CLASSPATH. The XmlBeanFactory() API takes care of creating and initializing all the objects, i.e. beans mentioned in the configuration file.
The second step is used to get the required bean using getBean() method of the created bean factory object. This method uses bean ID to return a generic object, which finally can be casted to the actual object. Once you have the object, you can use this object to call any class method.
Following is the content of the bean 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" xsi:schemaLocation = "http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> <bean id = "helloWorld" class = "com.tutorialspoint.HelloWorld"> <property name = "message" value = "Hello World!"/> </bean> </beans>
Output
Once you are done with creating the source and the bean configuration files, let us run the application. If everything is fine with your application, it will print the following message −
Your Message : Hello World!