java / beginner
Snippet
Constructor Dependency Injection
Constructor injection is the recommended way to handle dependencies in Spring. It ensures the object is always in a valid state and facilitates testing.
snippet.java
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@RestControllerpublic class CheckoutController {private final PaymentProcessor processor;public CheckoutController(PaymentProcessor processor) {this.processor = processor;}}
spring
Breakdown
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private final PaymentProcessor processor
The dependency is declared as final, ensuring it cannot be changed after initialization.
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public CheckoutController(...)
The constructor where Spring automatically injects the required dependency bean.