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SpringBoot五種獲取ApplicationContext的實(shí)現(xiàn)方式

更新時(shí)間：2025年09月19日 09:27:58 作者：enjoy編程

本文系統(tǒng)梳理了獲取Spring ApplicationContext的多種方式,包括創(chuàng)建工具類、實(shí)現(xiàn)ApplicationContextInitializer接口、ApplicationListener接口、啟動(dòng)類配置、ApplicationContextAware接口及@Resource注解注入,提供便捷的bean獲取與容器操作方案

1. 概念

ApplicationContext是什么？

簡單來說就是Spring中的容器，可以用來獲取容器中的各種bean組件，注冊監(jiān)聽事件，加載資源文件等功能

2. 獲取ApplicationContext的方式

2.1 創(chuàng)建工具類

通過此工具類，可以方便的獲取bean組件, 獲取配置信息等

import org.apache.commons.lang3.BooleanUtils;
import org.apache.commons.lang3.math.NumberUtils;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.core.env.Environment;

public class SpringUtil {
    private static ApplicationContext applicationContext = null;
    private static Environment environment = null;

    public static void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        if (SpringUtil.applicationContext == null) {
            SpringUtil.applicationContext = applicationContext;
            environment = applicationContext.getEnvironment();
            //TODO 設(shè)置后，可以做一些操作
        }
    }

    //獲取applicationContext
    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    public static Environment getEnvironment() {
        return environment;
    }

    //通過name獲取 Bean.
    public static Object getBean(String name) {
        return getApplicationContext().getBean(name);

    }

    //通過class獲取Bean.
    public static <T> T getBean(Class<T> clazz) {
        return getApplicationContext().getBean(clazz);
    }

    //通過name,以及Clazz返回指定的Bean
    public static <T> T getBean(String name, Class<T> clazz) {
        return getApplicationContext().getBean(name, clazz);
    }

    public static String getString(String key) {
        return environment.getProperty(key);
    }

    public static int getInt(String key) {
        return NumberUtils.toInt(environment.getProperty(key));
    }

    public static long getLong(String key) {
        return NumberUtils.toLong(environment.getProperty(key));
    }

    public static boolean getBoolean(String key) {
        return BooleanUtils.toBoolean(environment.getProperty(key));
    }
}

方式1. 實(shí)現(xiàn)ApplicationContextInitializer接口

實(shí)現(xiàn)接口后，將此類注入到Spring容器中，有兩種方式。當(dāng)然也可以直接調(diào)用靜態(tài)方法

第一種：在此類上加`@Component`注解
第二種：在 `resources/META-INF/spring.factories`文件中添加以下配置: org.springframework.context.ApplicationContextInitializer=CustomerApplicationContextInitializer的路徑

實(shí)現(xiàn)ApplicationContextInitializer的源碼示例：

public class CustomApplicationContextInitializer implements ApplicationContextInitializer {
  @Override
  public void initialize(ConfigurableApplicationContext applicationContext) {    
     SpringBeanUtils.setApplicationContext(applicationContext);
  }
}

方式2. 實(shí)現(xiàn)ApplicationListener接口

實(shí)現(xiàn)接口后，將此類注入到Spring容器中，有兩種方式。當(dāng)然也可以直接調(diào)用靜態(tài)方法

第一種：在此類上加`@Component`注解
第二種：在 `resources/META-INF/spring.factories`文件中添加以下配置: org.springframework.context.ApplicationContextInitializer=CustomerApplicationListener的路徑

實(shí)現(xiàn)ApplicationListener的源碼示例:

public class CustomApplicationListener implements ApplicationListener<ApplicationContextEvent> {
  @Override
  public void onApplicationEvent(ApplicationContextEvent event) {        
     SpringBeanUtils.setApplicationContext(event.getApplicationContext());
  }
}

方式3. 在啟動(dòng)類main方法中設(shè)置

@SpringBootApplication
@EnableSwagger2
public class Application {
    public static void main(String[] args) {
        ConfigurableApplicationContext applicationContext = SpringApplication.run(WangMikeSpringApplication.class, args);        
        SpringBeanUtils.setApplicationContext(applicationContext);
    }
}

方式4. 實(shí)現(xiàn)ApplicationContextAware接口

@Component
public class SpringBeanUtils implements ApplicationContextAware {
    private static ApplicationContext applicationContext;
    public  void setApplicationContext(ApplicationContext applicationContext){
        SpringBeanUtils.applicationContext = applicationContext;
    }

    public static ApplicationContext getApplicationContext(
        return applicationContext;
    }
}

方式5. 直接通過@Resource注解注入

@Component
@Order(value = 1)
@Slf4j
public class AppStartRunner implements org.springframework.boot.ApplicationRunner {
    protected static Logger logger = LoggerFactory.getLogger(AppStartRunner.class);

    @Resource
    ApplicationContext applicationContext;