spring service层循环引用问题


循环引用,也叫做循环依赖,就是AService类依赖了BService类,BService类又依赖AService类,例如:

public class AService{

@Autowired
private BService bService;

}


public class BService{

@Autowired
private AService aService;

}

在spring中,可以把A可以注入给B的同时,也可以把B注入给A,那么这时在该容器中,A和B就存在循环依赖问题。

报错信息如下:

Bean with name 'AServiceImpl' has been injected into other beans [BServiceImpl] in its raw version as part of a circular reference, but has eventually been wrapped. This means that said other beans do not use the final version of the bean. This is often the result of over-eager type matching - consider using 'getBeanNamesOfType' with the 'allowEagerInit' flag turned off, for example.

Spring中的bean根据作用域的不同,可以大体分为两类,singleton和prototype。singleton在一个容器中,只会有一个实例;而prototype在每次调用时,都会产生一个新的实例。

 

解决方法:

  •  可以在service中添加@lazy(true)。例如:
public class AService{

@Autowired
@Lazy(true)
private BService bService;

}


public class BService{

@Autowired
@Lazy(true)
private AService aService;

}
  • 在需要调用的函数中,手动获取spring容器中的bean。工具类如下:
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
@Component
public class SpringUtils implements BeanFactoryPostProcessor, ApplicationContextAware {

/** Spring应用上下文环境 */
private static ConfigurableListableBeanFactory beanFactory;

private static ApplicationContext applicationContext;

@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException
{
SpringUtils.beanFactory = beanFactory;
}

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

/**
* 获取对象
*
* @param name
* @return Object 一个以所给名字注册的bean的实例
* @throws org.springframework.beans.BeansException
*
*/
@SuppressWarnings("unchecked")
public static <T> T getBean(String name) throws BeansException
{
return (T) beanFactory.getBean(name);
}

/**
* 获取类型为requiredType的对象
*
* @param clz
* @return
* @throws org.springframework.beans.BeansException
*
*/
public static <T> T getBean(Class<T> clz) throws BeansException
{
T result = (T) beanFactory.getBean(clz);
return result;
}

/**
* 如果BeanFactory包含一个与所给名称匹配的bean定义,则返回true
*
* @param name
* @return boolean
*/
public static boolean containsBean(String name)
{
return beanFactory.containsBean(name);
}

/**
* 判断以给定名字注册的bean定义是一个singleton还是一个prototype。 如果与给定名字相应的bean定义没有被找到,将会抛出一个异常(NoSuchBeanDefinitionException)
*
* @param name
* @return boolean
* @throws org.springframework.beans.factory.NoSuchBeanDefinitionException
*
*/
public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException
{
return beanFactory.isSingleton(name);
}

/**
* @param name
* @return Class 注册对象的类型
* @throws org.springframework.beans.factory.NoSuchBeanDefinitionException
*
*/
public static Class<?> getType(String name) throws NoSuchBeanDefinitionException
{
return beanFactory.getType(name);
}

/**
* 如果给定的bean名字在bean定义中有别名,则返回这些别名
*
* @param name
* @return
* @throws org.springframework.beans.factory.NoSuchBeanDefinitionException
*
*/
public static String[] getAliases(String name) throws NoSuchBeanDefinitionException
{
return beanFactory.getAliases(name);
}

/**
* 获取aop代理对象
*
* @param invoker
* @return
*/
@SuppressWarnings("unchecked")
public static <T> T getAopProxy(T invoker)
{
return (T) AopContext.currentProxy();
}

/**
* 获取当前的环境配置,无配置返回null
*
* @return 当前的环境配置
*/
public static String[] getActiveProfiles()
{
return applicationContext.getEnvironment().getActiveProfiles();
}

/**
* 获取当前的环境配置,当有多个环境配置时,只获取第一个
*
* @return 当前的环境配置
*/
public static String getActiveProfile()
{
final String[] activeProfiles = getActiveProfiles();
return StringUtils.isNotEmpty(activeProfiles) ? activeProfiles[0] : null;
}
}

 


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