启用组件扫描时，如何通过子类构造函数注入父基元类型属性

Question

我有一个父类Car和一个子类Axio。因此，我正在尝试通过子构造函数中的super("Axio"(将参数传递给父类中的构造函数参数，然后将值分配给父类中定义的属性。当我尝试在 spring 启动中执行应用程序时，它会向我抛出一个异常，指出

Description:
Field car in com.test.efshop.controller.HelloController required a bean of type 'com.test.efshop.Axio' that could not be found.

Action:
Consider defining a bean of type 'com.test.efshop.Axio' in your configuration.

谁能告诉我如何在春季启动中实现这一目标？我的代码如下，

汽车类

package com.test.efshop;
public class Car {
private String carName;
public String getCarName() {
    return carName;
}
public void setCarName(String carName) {
    this.carName = carName;
}
public Car(String carName) {
    this.carName = carName;
}
public String print() {
    return "Car name is : "+carName;    
}
}

汽车类的子类，即 Axio

  package com.test.efshop;
    public class Axio extends Car{
    public Axio() {
        super("Axio");
    }   
    }

/

/主方法

package com.test.efshop;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.support.SpringBootServletInitializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;
@SpringBootApplication
public class DemoApplication extends SpringBootServletInitializer {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

控制器类

package com.test.efshop.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;
import com.test.efshop.Axio;
import com.test.efshop.Engine;
@Controller
public class HelloController {
    @Autowired
    private Axio car;
    @RequestMapping(value = "/hello")
    public ModelAndView print() {
        return new ModelAndView("index");
    }
    //This is the method which i used to return the value of Car class
    @RequestMapping(value = "/hello2")
    @ResponseBody
    public String print2() {
        return car.print();
    }

}

Answer 1

正如 pvpkiran 评论的那样，如果一个类不是春豆，你就不能@Autowire类。

选项 a( 将Axio类转换为服务或组件。

@Component
public class Axio extends Car {
    public Axio() {
        super("Axio");
    }   
}

选项 b( 定义类型 Axio 的 bean。

@SpringBootApplication
public class DemoApplication extends SpringBootServletInitializer {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
    @Bean
    public Axio myAxioBean() {
        return new Axio();
    }
}