Java Spring:NullPointerException在为静态属性注入bean时

我的主要课程如下：

package main;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import testbean.MySpringBeanWithDependency;

public class Main {

    public static MySpringBeanWithDependency mySpringBeanWithDependency;

    @Autowired
    public void setTest(MySpringBeanWithDependency mySpringBeanWithDependency) {
        Main.mySpringBeanWithDependency = mySpringBeanWithDependency;
    }

    public static void main(String[] args) {
        ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
        mySpringBeanWithDependency.run();
    }

}

package main;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import testbean.MySpringBeanWithDependency;
import writer.NiceWriter;
import writer.Writer;

@PropertySource("atm.properties")
@Configuration
public class AppConfig {

    @Bean
    public MySpringBeanWithDependency mySpringBeanWithDependency() {
        return new MySpringBeanWithDependency();
    }

    @Bean
    public Writer writer() {
        return new Writer();
    }

    @Bean 
    public NiceWriter niceWriter() {
        return new NiceWriter();
    }

}

我的AppConfig类如下所示：

package main;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import testbean.MySpringBeanWithDependency;

public class Main {

    public static MySpringBeanWithDependency mySpringBeanWithDependency;

    @Autowired
    public void setTest(MySpringBeanWithDependency mySpringBeanWithDependency) {
        Main.mySpringBeanWithDependency = mySpringBeanWithDependency;
    }

    public static void main(String[] args) {
        ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
        mySpringBeanWithDependency.run();
    }

}

package main;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import testbean.MySpringBeanWithDependency;
import writer.NiceWriter;
import writer.Writer;

@PropertySource("atm.properties")
@Configuration
public class AppConfig {

    @Bean
    public MySpringBeanWithDependency mySpringBeanWithDependency() {
        return new MySpringBeanWithDependency();
    }

    @Bean
    public Writer writer() {
        return new Writer();
    }

    @Bean 
    public NiceWriter niceWriter() {
        return new NiceWriter();
    }

}

虽然我正在实例化名为mySpringBeanWithDependency的bean并将其分配给静态字段，但run（）方法命令抛出了一个NullPointerException

---

我在一些答案中看到了注入静态场的解决方法，但我想它对我不起作用。有人能指出我哪里出了问题，我应该如何做到这一点吗？

Main

不是bean，也不是实例化的。我相信可能有一种方法可以将bean注入到静态字段中，但在需要时从应用程序上下文获取bean会更有意义：

public static void main(String[] args) {
    ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
    MySpringBeanWithDependency bean = context.getBean(MySpringBeanWithDependency.class);
    bean.run();
}

---

这不是依赖注入的工作方式。初始化静态字段是反模式的我试图避免getBean，因为我在spring文档中读到它应该被避免，它写在最后一段中，我不知道它不鼓励使用

getBean（）

，谢谢你的澄清。在这种情况下，我认为这样做的方法是，初始化上下文，并用

@PostConstruct

注释

run（）

方法，这意味着它在实例化时被调用。如果bean不是

Lazy

，它应该运行您的应用程序。不知道这是不是一个更好的方法，tho。