Utils：获取SpringContext上下文中的Bean

在使用多线程环境时，有些对象不是拖管在 Spring 容器中，但需要拿到 Bean 资源，是无法通过注入的方式的，就需要通过外部工具类来获取 Spring 上下文，再获取 Bean。

SpringContextUtil

@Component
public class SpringContextUtil implements ApplicationContextAware {

    private static ApplicationContext context;

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

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

    //通过name获取 Bean.
    /*public static Object getBean(String name) {
        return context.getBean(name);
    }*/

    //通过name获取 Bean.
    public static <T> T getBean(String beanName) {
        return (T) getApplicationContext().getBean(beanName);
    }

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

    //通过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);
    }

}

若是 SSM 框架项目,则需要在 XML 文件中将 SpringContextUtil 配置为 Bean

<!-- 注册为 bean -->
<bean id="springContextUtil" class="com.xxxxx.SpringContextUtil" scope="singleton" />

SpringUtils

import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationEvent;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Component;

import java.util.Map;

/**
 * Spring工具类
 */
@Slf4j
@Component
public class SpringUtil implements ApplicationContextAware {

    /**
     * spring全局配置项
     */
    private static ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext context) throws BeansException {
        if (applicationContext == null) {
            applicationContext = context;
            log.info("ApplicationContext init success,you can invoke by SpringUtil.getApplicationContext() to get ApplicationContext,init bean count="
                    + applicationContext.getBeanDefinitionCount() + ",bean=" + JSONObject.toJSONString(applicationContext.getBeanDefinitionNames()));
        }
    }

    /**
     * @return spring全局配置项
     */
    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    /**
     * 通过name获取 Bean.
     *
     * @param name
     * @return
     */
    public static <T> T getBean(String name) {
        return (T) applicationContext.getBean(name);
    }

    /**
     * 通过class获取Bean.
     *
     * @param clazz
     * @return
     */
    public static <T> T getBean(Class<T> clazz) {
        return applicationContext.getBean(clazz);
    }

    /**
     * 通过name,以及Clazz返回指定的Bean
     *
     * @param name
     * @param clazz
     * @return
     */
    public static <T> T getBean(String name, Class<T> clazz) {
        return applicationContext.getBean(name, clazz);
    }

    /**
     * 获取实现相关接口的类关系
     *
     * @param clazz
     * @return
     */
    public static <T> Map<String, T> getBeansOfType(Class<T> clazz) {
        return applicationContext.getBeansOfType(clazz);
    }

    /**
     * 发布事件
     *
     * @param event
     */
    public static void publishEvent(ApplicationEvent event) {
        applicationContext.publishEvent(event);
    }

    /**
     * 获取环境信息
     */
    public static Environment getEnvironment() {
        return applicationContext.getEnvironment();
    }
}

@Slf4j是基于Lombok的插件。