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springautowiredconvention-over-configur

Is there anyway to eliminate spring-context xml and turn on annotations programatically?


I am new bee in spring and was playing with 'Autowired' annotation in my small test program. So far, I have learned that to make 'Autowired' annotation work we need to turn it on from the spring- context xml using the tag:

<context:annotation-config />

I was wondering if there is any way to eliminate xml and turn on annotation from program.

Here is my spring program that is working with spring context defined in xml .

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


            <context:annotation-config />

            <!-- bean definitions go here -->

            <bean id="mainClass" class="com.myproject.spring.MyTester" />
            <bean id="student" class="com.myproject.spring.model.Student" scope="prototype" />
</beans>

My Bean:

package com.myproject.spring.model;



public class Student
{
    private String name = "Johhn Hasel";


    public String getName()
    {
        return name;
    }


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

    @Override 
    public String toString() {
        return name;
    }

}

And my main class for this application :

package com.myproject.spring;

import com.myproject.spring.model.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTester
{

    @Autowired
    private Student student;


    public static void main( String[] args )
    {

       ApplicationContext context = new ClassPathXmlApplicationContext("SpringContext.xml");
        MyTester mtster = context.getBean( MyTester.class );

        System.out.println(mtster.student.toString()); 

    }



}

Solution

  • If you have a pure standalone application you need at minimum to

    1. annotate your student class with @Component
    2. Annotate your MyTester class with @ComponentScan and @Configuration
    3. Exchange the ClassPathXmlApplicationContext(..) with new AnnotationConfigApplicationContext(MyTester.class)

    What happen behind the scenes is

    1. that you mark your Student as a class available for auto-discovery
    2. set the MyTester class as the starting point for scanning components and as a class which may contain configurations like @Bean definitions
    3. Tell Spring to use the Annotation driven configuration with the starting point in MyTester class