You are free to use any of the standard Spring Framework techniques to define your beans and their injected dependencies.
We often find that using @ComponentScan (to find your beans) and using @Autowired (to do constructor injection) works well.
If you structure your code as suggested above (locating your application class in a root package), you can add @ComponentScan without any arguments.
All of your application components (@Component, @Service, @Repository, @Controller etc.) are automatically registered as Spring Beans.
The following example shows a @Service Bean that uses constructor injection to obtain a required RiskAssessor bean:
package com.example.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class DatabaseAccountService implements AccountService {
private final RiskAssessor riskAssessor;
@Autowired
public DatabaseAccountService(RiskAssessor riskAssessor) {
this.riskAssessor = riskAssessor;
}
// ...
}If a bean has one constructor, you can omit the @Autowired, as shown in the following example:
@Service
public class DatabaseAccountService implements AccountService {
private final RiskAssessor riskAssessor;
public DatabaseAccountService(RiskAssessor riskAssessor) {
this.riskAssessor = riskAssessor;
}
// ...
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Tip
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Notice how using constructor injection lets the riskAssessor field be marked as final, indicating that it cannot be subsequently changed.
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