spring 应用程序上下文未找到配置 bean

Question

I have a configuration class:

@Configuration
public class MyConfig {
    @Value(value = "${com.test.myValue")
    private String myValue;
    
    public String getMyValue() {
        return myValue;
    }
}

And a non-bean class that use it:

public class MyPOJO {
    private static MyConfig config = SpringContext.getBean(MyConfig.class);
    
    public String getMyValue() {
        return config.getMyValue();
    }
}

And this is the SpringContext class that I use to get the bean:

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
public class SpringContext implements ApplicationContextAware {

    private static ApplicationContext context;

    /**
     * Returns the Spring managed bean instance of the given class type if it exists. Returns null
     * otherwise.
     * 
     * @param beanClass
     * @return
     */
    public static <T extends Object> T getBean (Class<T> beanClass) {
        return context.getBean(beanClass);
    }

    @Override
    public void setApplicationContext (ApplicationContext context) throws BeansException {
        SpringContext.context = context;
    }
}

but when I run this code:

MyPOJO pojo = new MyPOJO();
String value = pojo.getMyValue();

it fails on NullPointerException on return config.getMyValue(); which means config is null and wasn't created.

what could be the issue?

note that I don't believe it's an issue with component scan since i have an annotation that scan the entire package.

Answer 1

You have mistakes in the MyConfig class:

1. There is no closing curly bracket }
2. Two different types for the myValue .

@Configuration
public class MyConfig {
    @Value(value = "${com.test.myValue}")
    private Integer myValue;

    public Integer getMyValue() {
        return myValue;
    }
}

Also, it's important to know the context when you create the POJO. You should ensure that POJO creation is fulfilled before the Spring context is ready.