What are the ways to get ApplicationContext object in Spring?

Question

Hi i want to know what are the different ways to get ApplicationContext Object in Spring? I know only one way that is,

ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");

is there any other ways? if it is please let me know.

Thanks.

Answer 1

You can also use annotation based configuration

@Configuration
public class Config {

    @Bean
    public Bean1 bean1() {
        return new Bean1();
    }

    public static void main(String[] args) {
        ApplicationContext ctx = new AnnotationConfigApplicationContext(Config.class);
    }
}

Answer 2

You can implement the interface ApplicationContextAware , like this :

public class MyClass implements ApplicationContextAware {

    private ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

}

If you are using annotation, you could also autowire it

@Autowired
private ApplicationContext applicationContext;

Also, the code you wrote does not get an existing application context, it creates one.

Answer 3

Well, there are a lot of ways out there, I wonder whom would know them all...

But first, we need to make a difference between instanting a new context, or getting a running and existing application-context.

By new ***ApplicationContext a new context will be created. Therefore all Subclasses of org.springframework.context.ApplicationContext can be used to create a new ApplicationContext. You can find all implementing classes here . The new way to instantiate a spring-context is through AnnotationConfigApplicationContext .

Also, you can add a displatcher-servlet or an servlet-listener in your web.xml. Or use a framework like gemini-blueprint in an osgi-environment which starts all xml-files in meta-inf/spring. (eg eclipse virgo)

On the other hand, you can get an existing context (which means not a new one) through different ways:

1. ApplicationContextAware

Implement the ApplicationContextAware interface and you will get the context via setApplicationContext(ApplicationContext applicationContext) method.

2. Just add @Autowired private ApplicationContext applicationContext; to your spring bean. But make sure it is a spring bean.

3. In your web-application, you can get the context of your listener-context via ApplicationContextUtils.getWebApplicationContext( servletcontext)

There would a lot of more ways, but these are those which popped up in my mind quickly.

Answer 4

If you are referring to the possible way you can create an ApplicationContext and not to the ways such an instance can be passed through your code then I suggest taking a look at the Spring javadoc for ApplicationContext . So based on this the concrete implementations of this interface are:

org.springframework.context.annotation.AnnotationConfigApplicationContext

Standalone application context, accepting annotated classes as input - in particular @Configuration-annotated classes, but also plain @Component types and JSR-330 compliant classes using javax.inject annotations. Allows for registering classes one by one using register(Class...) as well as for classpath scanning using scan(String...).

org.springframework.web.context.support.AnnotationConfigWebApplicationContext

This is essentially the equivalent of AnnotationConfigApplicationContext for a web environment.

org.springframework.context.support.ClassPathXmlApplicationContext

Standalone XML application context, taking the context definition files from the class path, interpreting plain paths as class path resource names that include the package path (eg "mypackage/myresource.txt"). Useful for test harnesses as well as for application contexts embedded within JARs.

org.springframework.context.support.FileSystemXmlApplicationContext

Standalone XML application context, taking the context definition files from the file system or from URLs, interpreting plain paths as relative file system locations (eg "mydir/myfile.txt"). Useful for test harnesses as well as for standalone environments.

org.springframework.context.support.GenericApplicationContext

Generic ApplicationContext implementation that [...] does not assume a specific bean definition format

org.springframework.context.support.GenericXmlApplicationContext

Convenient application context with built-in XML support. This is a flexible alternative to ClassPathXmlApplicationContext and FileSystemXmlApplicationContext, to be configured via setters, with an eventual AbstractApplicationContext.refresh() call activating the context.

org.springframework.context.support.GenericGroovyApplicationContext

An ApplicationContext implementation that extends GenericApplicationContext. [...] Consider this as the equivalent of GenericXmlApplicationContext for Groovy bean definitions, or even an upgrade thereof since it seamlessly understands XML bean definition files as well.

org.springframework.web.context.support.GenericWebApplicationContext

Subclass of GenericApplicationContext, suitable for web environments.

org.springframework.web.context.support.GroovyWebApplicationContext

WebApplicationContext implementation which takes its configuration from Groovy bean definition scripts and/or XML files, as understood by an GroovyBeanDefinitionReader. This is essentially the equivalent of GenericGroovyApplicationContext for a web environment.

org.springframework.jca.context.ResourceAdapterApplicationContext

ApplicationContext implementation for a JCA ResourceAdapter. Needs to be initialized with the JCA BootstrapContext, passing it on to Spring-managed beans that implement BootstrapContextAware.

org.springframework.context.support.StaticApplicationContext

ApplicationContext implementation which supports programmatic registration of beans and messages, rather than reading bean definitions from external configuration sources. Mainly useful for testing.

org.springframework.web.portlet.context.StaticPortletApplicationContext

Static Portlet-based ApplicationContext implementation for testing. Not intended for use in production applications.

org.springframework.web.context.support.StaticWebApplicationContext

Static WebApplicationContext implementation for testing. Not intended for use in production applications.

org.springframework.web.portlet.context.XmlPortletApplicationContext

Portlet-based WebApplicationContext implementation which takes its configuration from XML documents, understood by an XmlBeanDefinitionReader.

org.springframework.web.context.support.XmlWebApplicationContext

WebApplicationContext implementation which takes its configuration from XML documents, understood by an XmlBeanDefinitionReader. This is essentially the equivalent of GenericXmlApplicationContext for a web environment.