spring 3 annotation dependency injection

Question

For a new legacy application I have to use Latest Spring framework 3.x with Hibernate 3.x. Earlier I used Spring IoC with xml configuration. Now i would like to go for annotation based IoC.

Below link from rose india shows use annotation without xml file. rose india

but i have found some other way of implementing in another site: blog

I am confused here which way to implement IoC with latest technology. Please refer some good site for sample. Also please share some sample code for IoC with annotation.

EDIT:

Spring reference document 3.x says use @Configuration or xml configuration i.e. with annotation <context:annotation-config/>. Which one is better to use? Why?

Solution 1

Your best bet is to start with the Spring 3.0 Documentation. If you already are familiar with Dependency Injection using xml configuration, take a look at Spring's annotation support in Section 3.9 Annotation-based container configuration. There should be plenty of details there to help get you started.

If this is not a WebApp, and you need to load the ApplicationContext yourself, you should take a look at Section 3.11 Java-based container configuration. This section details how you can create your ApplicationContext with your xml configuration.

I would recommend using the @Autowired annotations for wiring with @Component annotation for defining beans within the ApplicationContext, and use the scan(String) method provided by the AnnotationConfigApplicationContext to find all annotated components:

public static void main(String[] args) {
  AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
  ctx.scan("your.package.here");
  ctx.refresh();
  MyService myService = ctx.getBean(MyService.class);
  //use myService
}

Solution 2

Here is a simple and clear one:

http://www.simplespringtutorial.com/annotations.html

Solution 3

I suggest going with adding: <context:annotation-config /> to your xml context file to have it load the annotations. Then use: <context:component-scan base-package="my.package" /> to import all the annotated classes. This requires no code whatsoever and is incredibly clean. You can also add include/exclude filters to the scan in the xml file.

Then, just use whatever annotations you want in your classes. Make sure of the annotation construction to give them IDs for referencing later, i.e. @Component("mycomponentbean").

Comments

[TechFind]

do i need to use new AnnotationConfigApplicationContext(); to load xml file? only bean declaration is sufficient in xml file?

[TechFind]

ok, in my context xml file do i need to specify bean id and its property for IoC?

[Tony]

You can just add: <context:annotation-config /> to your context.xml file to have it load the annotations. Then use: <context:component-scan base-package="my.package" /> to import all the annotated classes. This requires no code whatsoever.

[hellojava]

@gupta59 Thanks. Fixed