springboot實戰 獲取spring上下文的4種方式

實際開發中我們經常需要通過spring上下文獲取一些配置信息，本文闡述springboot應用獲取spring上下文的幾種方式。

方式一：實現ApplicationContextAware接口

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

/**
 * 實現ApplicationContextAware接口設置applicationContext
 * 提供static方法供調用者使用，不要求使用者受spring容器管理
 */
@Component
public class SpringContextUtil1 implements ApplicationContextAware {

    public static ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        SpringContextUtil1.applicationContext = applicationContext;
    }

    public static ApplicationContext getApplicationContext() {
        return SpringContextUtil1.applicationContext;
    }

    public static Object getBean(String name) {
        return getApplicationContext().getBean(name);
    }

    public static <T> T getBean(Class<T> clazz) {
        return getApplicationContext().getBean(clazz);
    }

    public static <T> T getBean(String name, Class<T> clazz) {
        return getApplicationContext().getBean(name, clazz);
    }
}

方式二：非static方法版

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

/**
 * 實現ApplicationContextAware接口設置applicationContext
 * 如果使用者也是被spring管理的bean則可以使用注入的方式使用,而非調用static方法
 */
@Component
public class SpringContextUtil2 implements ApplicationContextAware {

    public ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

    public ApplicationContext getApplicationContext() {
        return this.applicationContext;
    }

    public Object getBean(String name) {
        return applicationContext.getBean(name);
    }

    public <T> T getBean(Class<T> clazz) {
        return applicationContext.getBean(clazz);
    }

    public <T> T getBean(String name, Class<T> clazz) {
        return getApplicationContext().getBean(name, clazz);
    }
}


@Component
public class ContextUser{

    /**
     * 使用者直接注入
     */
    @Autowired
    public SpringContextUtil2 springContextUtil2;
 
}

方式三：在springboot引導類裏設置

import org.springframework.context.ApplicationContext;

/**
 * 在springboot引導類裏設置applicationContext
 * 工具類無需實現ApplicationContextAware接口
 */

public class SpringContextUtil3 {

    public static ApplicationContext applicationContext;

    public static ApplicationContext getApplicationContext() {
        return SpringContextUtil3.applicationContext;
    }

    public static void setApplicationContext(ApplicationContext applicationContext) {
        SpringContextUtil3.applicationContext = applicationContext;
    }

    public static Object getBean(String name) {
        return getApplicationContext().getBean(name);
    }

    public static Object getBean(Class<?> requiredType) {
        return getApplicationContext().getBean(requiredType);
    }

    public static <T> T getBean(String name, Class<T> clazz) {
        return getApplicationContext().getBean(name, clazz);
    }
}


//在springboot引導類裏設置applicationContext
@SpringBootApplication
public class MainApplication {

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(MainApplication.class, args);
        SpringContextUtil3.setApplicationContext(context);
    }
}

方式四：直接注入ApplicationContext

@Component
public class ContextUser{

    /**
     * 在需要使用上下文的地方直接注入(前提：使用者受spring容器管理)
     */
   @Autowired
   public ApplicationContext applicationContext;
 
}