bean in spring

Innocent Iguana answered on March 20, 2024 Popularity 9/10 Helpfulness 3/10

answer bean in spring

bean in spring

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// POJO: Any java object is POJO or Plain Old Java Object
// Java Bean (or EJB): POJO with 3 restrictions (No argument constructor, getters and setters, implements Serializable)
// Spring Bean: Anything that is managed by Spring IoC (POJO or even struct like int, double etc)
// Person.java
public record Person (String name, int age, Address address) { };

// Address.java
public record Address(String firstLine, String city){ };

@Configuration
public class HelloWorldConfiguration {
	
	// Creating Independent Beans
	@Bean //  Bean 1 : Independent
	public String name() {
		return "Abir";
	}
	
	@Bean // Bean 2 : Independent
	public int age() {
		return 32;
	}
	
	@Bean(name = "customAddress") // Bean 3 : Independent with custom bean name
	@Primary // If there are multiple candidate Beans of same class type, make one bean as default bean 
	public Address address() {
		return new Address("Uttara", "Dhaka");		
	}

	@Bean // Bean 4 : Independent 
	@Qualifier("address2qualifier") 
	public Address address2() {
		return new Address("Rampura", "Dhaka");		
	}

	@Bean //  Bean 5 : Independent
	public Person person1() {
		return new Person("Ashik", 26, new Address("Narail", "Khulna"));		
	}

	@Bean // Bean 6 : Dependent on Bean 1,2 and 3 (uses method call to get the required Beans)
	public Person person2MethodCall() {
		return new Person(name(), age(), address()); //name, age		
	}

	@Bean // Bean 7 : Dependent on Bean 1,2 and 3 (uses method names as parameters to get the required Beans) 
	@Primary // If there are multiple candidate Beans of same class type, make one bean as default bean 
	// No ...... available: expected single matching bean but found 2: customAddress,address2
	public Person person3ParameterCall(String name, int age, Address someAddress) {
		return new Person(name, age, customAddress);	
	}

	@Bean // Bean 8 : Dependent on Bean 1,2 and 4 (uses method names as parameters to get the required Beans) 
	// If there are multiple candidate Beans of same type, make each bean hold an identity called qualifier that will autowire it
	public Person person5Qualifier(String name, int age, @Qualifier("address2qualifier") Address anotherAddress) {
		return new Person(name, age, anotherAddress); //name, age		
	}

	
}

Popularity 9/10 Helpfulness 3/10 Language java

Source: Grepper

Tags: java spring

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Contributed on Mar 20 2024

Innocent Iguana

0 Answers Avg Quality 2/10

bean in spring

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