Inject parameters to constructor through annotation in Spring

Question

I am using Spring Boot annotation configuration. I have a class whose constructor accepts 2 parameters (string, another class).

Fruit.java

public class Fruit {
    public Fruit(String FruitType, Apple apple) {
            this.FruitType = FruitType;
            this.apple = apple;
        }
}

Apple.java

public class Apple {

}

I have a class that needs to autowire the above class by injecting parameters to the constructor("iron Fruit",Apple class)

Cook.java

public class Cook {

    @Autowired
    Fruit applefruit;
}

The cook class need to autowire Fruit class with parameters("iron Fruit",Apple class)

The XML configuration looks like this:

<bean id="redapple" class="Apple" />
<bean id="greenapple" class="Apple" />
<bean name="appleCook" class="Cook">
          <constructor-arg index="0" value="iron Fruit"/>
          <constructor-arg index="1" ref="redapple"/>
</bean>
<bean name="appleCook2" class="Cook">
          <constructor-arg index="0" value="iron Fruit"/>
          <constructor-arg index="1" ref="greenapple"/>
</bean>

How to achieve it using annotation configuration only?

medvedev1088 medvedev1088 · Accepted Answer · 2015-05-29T14:53:35

Apple must be a spring-managed bean:

@Component
public class Apple{

}

Fruit as well:

@Component
public class Fruit {

    @Autowired
    public Fruit(
        @Value("iron Fruit") String FruitType,
        Apple apple
        ) {
            this.FruitType = FruitType;
            this.apple = apple;
        }
}

Note the usage of @Autowired and @Value annotations.

Cook should have @Component too.

Update

Or you could use @Configuration and @Bean annotations:

@Configuration 
public class Config {

    @Bean(name = "redapple")
    public Apple redApple() {
        return new Apple();
    }

    @Bean(name = "greeapple")
    public Apple greenApple() {
        retturn new Apple();
    }

    @Bean(name = "appleCook")
    public Cook appleCook() {
        return new Cook("iron Fruit", redApple());
    }
    ...
}

Inject parameters to constructor through annotation in Spring

1 Answers