背景

在平时的工作中存在一些我们new出来的对象,这些对象需要依赖Spring容器中的bean。

但是如何优雅地设置Spring容器中的bean到我们new出来的对象中呢。

1.使用FactoryBean

package dcs.thread;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
 
@Component
public class DataCompareRunnableFactoryBean implements FactoryBean {
​
    @Autowired
    DataCompareService dataCompareService;
​
    @Override
    public Object getObject() throws Exception {
        return new DataCompareRunnable(dataCompareService);
    }
​
    @Override
    public Class<?> getObjectType() {
        return DataCompareRunnable.class;
    }
​
    @Override
    public boolean isSingleton() {
        return false;
    }
}

2.使用SpringContextUtil

package utils;
​
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
​
import java.util.Map;
import java.util.Optional;
​
/**
 * @Description: Spring 上下文工具, 可用于获取spring 容器中的Bean
 */
@Component
public class SpringContextUtil implements ApplicationContextAware {
​
    private static ApplicationContext applicationContext;
​
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        SpringContextUtil.applicationContext = applicationContext;
    }
​
    /**
     * @Description: 获取spring容器中的bean,通过bean名称获取
     * @param beanName bean名称
     * @return: Object 返回Object,需要做强制类型转换
     */
    public static Object getBean(String beanName){
        return applicationContext.getBean(beanName);
    }
​
    /**
     * @Description: 获取spring容器中的bean, 通过bean类型获取
     * @param beanClass bean 类型
     * @return: T 返回指定类型的bean实例
     */
    public static <T> T getBean(Class<T> beanClass) {
​
        return applicationContext.getBean(beanClass);
    }
​
    public static <T> Optional<T> getBeanOptional(Class<T> beanClass) {
        try {
            T bean = applicationContext.getBean(beanClass);
            return Optional.of(bean);
        } catch (Exception e) {
            return Optional.empty();
        }
    }
​
    /**
     * @Description: 获取spring容器中的bean, 通过bean名称和bean类型精确获取
     * @param beanName bean 名称
     * @param beanClass bean 类型
     * @return: T 返回指定类型的bean实例
​
     */
    public static <T> T getBean(String beanName, Class<T> beanClass){
        return applicationContext.getBean(beanName,beanClass);
    }
​
    public static <T> Map<String, T> getBeansOfType(Class<T> beanClass) {
        return applicationContext.getBeansOfType(beanClass);
    }
​
}

举例说明:

public class MyClass {
    private OtherClass otherClass = SpringContextUtil.getBeansOfType(OtherClass.class)
}