Springboot 如何获取上下文对象

Springboot 上下文 对象获取

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									package it.benjamin.aspirinweb.mem; 

									import org.springframework.beans.BeansException;

									import org.springframework.context.ApplicationContext;

									import org.springframework.context.ApplicationContextAware;

									import org.springframework.stereotype.Component; 

									/**

									 * 获取Springboot上下文，通过上下文可以拿到配置文件中的配置参数

									 */

									@Component

									public class AppContextTool implements ApplicationContextAware {

									    private static ApplicationContext context;

									    public String getConfig(String key) {

									        return context.getEnvironment().getProperty(key);

									    }

									    @Override

									    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

									        this.context = applicationContext;

									    } 

									}

或者更简单的写法：

定义一个AppUtil.java类：

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									public class AppUtil {

									    public static ConfigurableApplicationContext CONTEXT;

									}

在启动类中进行赋值

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									public static void main(String[] args) {

									        AppUtil.CONTEXT = SpringApplication.run(RedisFlinkApplication.class, args);

									}

spring boot获取上下文随时取出被spring管理的bean对象

方法一：

实现ApplicationContextAware，重写setApplicationContext方法。这个方式下，工具类也被注册成了Bean，既然这样，那就必须确保该类能被Spring自动扫描到。

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									@Component

									public class SpringContextUtils implements ApplicationContextAware { 

									    private static ApplicationContext applicationContext;

									    @Override

									    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

									        SpringContextUtils.applicationContext = applicationContext;

									    }

									    public static <T> T getBean(Class<T> cls) {

									        if (applicationContext == null) {

									            throw new RuntimeException("applicationContext注入失败");

									        }

									        return applicationContext.getBean(cls);

									    }

									    public static Object getBean(String name) {

									        if (applicationContext == null) {

									            throw new RuntimeException("applicationContext注入失败");

									        }

									        return applicationContext.getBean(name);

									    }

									    public static <T> T getBean(String name, Class<T> cls) {

									        if (applicationContext == null) {

									            throw new RuntimeException("applicationContext注入失败");

									        }

									        return applicationContext.getBean(name, cls);

									    }

									    public static HttpServletRequest getRequest() {

									        ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder

									            .getRequestAttributes();

									        return requestAttributes == null ? null : requestAttributes.getRequest();

									    }

									}

方式二：

我想要的工具类，往往会部署在公共jar中，一般情况下不能被SpringBoot程序扫描到。所有就有手动注入上下文的方式。

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									@Slf4j

									public class SpringUtils { 

									    private SpringUtils() {

									    } 

									    private static ApplicationContext context = null;

									    /**

									     * 初始化Spring上下文

									     *

									     * @param ctx 上下文对象

									     */

									    public static void initContext(ApplicationContext ctx) {

									        if(ctx == null) {

									            log.warn("ApplicationContext is null.");

									            return;

									        }

									        context = ctx;

									    } 

									    /**

									     * 根据类型获取Bean

									     *

									     * @param cls Bean类

									     * @param <T> Bean类型

									     * @return Bean对象

									     */

									    public static <T> T getBean(Class<T> cls) {

									        return context == null ? null : context.getBean(cls);

									    }

									    /**

									     * 根据名称获取Bean

									     *

									     * @param name Bean名称

									     * @return Bean对象

									     */

									    public static Object getBean(String name) {

									        return context == null ? null : context.getBean(name);

									    }

									    /**

									     * 根据Bean名称和类获取Bean对象

									     *

									     * @param name Bean名称

									     * @param cls Bean类

									     * @param <T> Bean类型

									     * @return Bean对象

									     */

									    public static <T> T getBean(String name, Class<T> cls) {

									        return context == null ? null : context.getBean(name, cls);

									    }

									}

此种方式不用实现ApplicationContextAware接口，但是需要手动设置上下文。所以在程序入口处，需要调用initContext方法，完成上下文的初始化。

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									public static void main(String[] args) {

									    ApplicationContext context = SpringApplication.run(YCloudsServiceBApplication.class, args);

									    SpringUtils.initContext(context);

									}