我如何在配置 class 中查看自动装配方法的 output

Question

@Configuration
@ComponentScan(basePackages = "com.test")
public class Config {
    
    @Autowired
    public int fun(SampleClass obj) {
        return obj.num;
    }
    
    @Bean
    public SampleClass get() {
        return new SampleClass();
    }
    
}

In this code I can call the Bean method from my main class like this,

ApplicationContext ctx = new AnnotationConfigApplicationContext(Config.class);
SampleClass obj = ctx.getBean(SampleClass.class);

But how can I call the Autowired method. Or if i cannot then where can i see the output to the same.

And also this is my SampleClass.java

public class SampleClass {
    int num;
    SampleClass(){
        System.out.println("inside constructor of sample class");
        num = 4;
    }
}

Answer 1

Answering you question as-is

Config class is also a bean, so calling its method is quite straightforward:

ApplicationContext ctx = new AnnotationConfigApplicationContext(Config.class);
Config config = ctx.getBean(Config.class);
SampleClass sampleClass = ctx.getBean(SampleClass.class);
System.out.println(config.fun(sampleClass));

Possible misunderstanding of how @Autowired on method works

I think you might misunderstood how this works. When you put @Autowired on a regular method, spring only treats this method as init method , ie spring calls it once during context initialisation and that is it. It doesn't change behaviour of this method if you are going to call it directly.

As a hands-on exercise, add System.out.println("Init"); in fun() method and create context without any method calls ( ApplicationContext ctx = new AnnotationConfigApplicationContext(Config.class); You will see that Init will be printed.