10.0 Spring Container Using Java Code

Spring Container Configuration using pure Java class

Instead of configuring Spring container using XML we'll use pure java class to configure.

Three ways to configure Spring container

1. Full XML Config
2. XML Component Scan
3. Java Configuration Class

Java Configuration Class for configuring Spring Container

Configuring Java class instead of xml

@Configuration

@ComponentScan("com.demo.spring")

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Movie.java

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package com.demo.spring;

public interface Movie {

public String getMovie();

public String getCategory();

}

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Category.java

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package com.demo.spring;

public interface Category {

public String getCategory();

}

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Comedy.java

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package com.demo.spring;

import org.springframework.stereotype.Component;

@Component

public class Comedy implements Category {

@Override

public String getCategory() {

return "Life is a comedy";

}

}

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Bollywood.java

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package com.demo.spring;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Component;

@Component("bollywood")

public class Bollywood implements Movie {

@Autowired

Category cat;

@Override

public String getMovie() {

return "Bollywood movies have thousands of varities";

}

@Override

public String getCategory() {

return cat.getCategory();

}

}

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Comedy.java

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package com.demo.spring;

import org.springframework.stereotype.Component;

@Component

public class Comedy implements Category {

@Override

public String getCategory() {

return "Life is a comedy";

}

}

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MyApp.java

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package com.demo.spring;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyApp {

public static void main(String args[])

{

AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext(MovieConfig.class);

Movie obj=context.getBean("bollywood",Movie.class);

System.out.println(obj.getMovie());

System.out.println(obj.getCategory());

context.close();

}

}

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MovieConfig.java

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package com.demo.spring;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.ComponentScan;

import org.springframework.context.annotation.Configuration;

import org.springframework.context.annotation.PropertySource;

@Configuration

@ComponentScan("com.demo.spring")

public class MovieConfig {

}

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OUTPUT

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Feb 27, 2018 3:07:54 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh

INFO: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@1963006a: startup date [Tue Feb 27 03:07:54 IST 2018]; root of context hierarchy

Bollywood movies have thousands of varities

Life is a comedy

Feb 27, 2018 3:07:54 AM org.springframework.context.support.AbstractApplicationContext doClose

INFO: Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@1963006a: startup date [Tue Feb 27 03:07:54 IST 2018]; root of context hierarchy

Configuring bean in java config without using  @ComponentScan

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Action.java // no @Component annotation

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package com.demo.spring;

public class Action implements Category {

@Override

public String getCategory() {

return "Coding is the only Action i believe in";

}

}

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Hollywood.java - // basic constructor injection

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package com.demo.spring;

import org.springframework.beans.factory.annotation.Value;

public class Hollywood implements Movie {

private Category cat;

public Hollywood(Category thecat){

cat=thecat;

}

@Override

public String getMovie() {

return "Graphics in Hollywood movies is a real-feel kind";

}

@Override

public String getCategory() {

return cat.getCategory();

}

}

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MovieConfig.java -// defining the individual bean without @ComponentScan

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package com.demo.spring;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.ComponentScan;

import org.springframework.context.annotation.Configuration;

import org.springframework.context.annotation.PropertySource;

@Configuration

public class MovieConfig {

//defining bean for action category note: getCategory() is the bean id

@Bean

public Category getCategory(){

return new Action();

}

//define bean for Hollywood and inject dependency // hollywood is the bean id

@Bean

public Movie hollywood(){

return new Hollywood(getCategory());

}

}

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HollywoodConfigJavaDemo.java

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package com.demo.spring;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class HollywoodConfigJavaDemo {

public static void main(String args[])

{

AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext(MovieConfig.class);

Movie obj=context.getBean("hollywood",Movie.class);

System.out.println(obj.getMovie());

System.out.println(obj.getCategory());

}

}

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OUTPUT

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Feb 27, 2018 3:14:45 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh

INFO: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@1963006a: startup date [Tue Feb 27 03:14:45 IST 2018]; root of context hierarchy

Graphics in Hollywood movies is a real-feel kind

Coding is the only Action i believe in

Feb 27, 2018 3:14:45 AM org.springframework.context.support.AbstractApplicationContext doClose

INFO: Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@1963006a: startup date [Tue Feb 27 03:14:45 IST 2018]; root of context hierarchy

Reading variables form a property file

literal injection using @PropertySource("classpath:bikesh.properties") &

@Value

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Hollywood.java

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package com.demo.spring;

import org.springframework.beans.factory.annotation.Value;

public class Hollywood implements Movie {

private Category cat;

@Value("${foo.name}")

private String name;

public String getName() {

return name;

}

public String getEmail() {

return email;

}

@Value("${foo.email}")

private String email;

public Hollywood(Category thecat){

cat=thecat;

}

@Override

public String getMovie() {

return "Graphics in Hollywood movies is a real-feel kind";

}

@Override

public String getCategory() {

return cat.getCategory();

}

}

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MovieConfig.java

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package com.demo.spring;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.ComponentScan;

import org.springframework.context.annotation.Configuration;

import org.springframework.context.annotation.PropertySource;

@Configuration

@PropertySource("classpath:bikesh.properties")

public class MovieConfig {

//defining bean for action category

@Bean

public Category getCategory(){

return new Action();

}

//define bean for Hollywood and inject dependency

@Bean

public Movie hollywood(){

return new Hollywood(getCategory());

}

}

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Hollywood.java

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package com.demo.spring;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class HollywoodConfigJavaDemo {

public static void main(String args[])

{

AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext(MovieConfig.class);

Movie obj=context.getBean("hollywood",Movie.class);

System.out.println(obj.getMovie());

System.out.println(obj.getCategory());

Hollywood obj1=context.getBean("hollywood",Hollywood.class);

System.out.println(obj1.getName());

System.out.println(obj1.getEmail());

context.close();

}

}

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OUTPUT

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Feb 27, 2018 3:15:26 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh

INFO: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@1963006a: startup date [Tue Feb 27 03:15:26 IST 2018]; root of context hierarchy

Graphics in Hollywood movies is a real-feel kind

Coding is the only Action i believe in

Bikesh Kumar

bikesh.kumar@tiwari.com

Feb 27, 2018 3:15:27 AM org.springframework.context.support.AbstractApplicationContext doClose

INFO: Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@1963006a: startup date [Tue Feb 27 03:15:26 IST 2018]; root of context hierarchy