【SpringBoot】在IOC之外的類中使用IOC內部的Bean

某些時候，某些類是不歸IOC管的，如我們的一些Util，如何使用IOC中的Bean？

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1、寫一個SpringUtil類，該類用于操縱Spring的ApplicationContext

@Component的注解是需要的，該Util是要被Spring管理的。

@Component
public class SpringUtil implements ApplicationContextAware
{private static ApplicationContext applicationContext;@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException{if (SpringUtil.applicationContext == null){SpringUtil.applicationContext = applicationContext;}}public static ApplicationContext getApplicationContext(){return 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);}
}

2、通過@Bean注解，返回一個Bean；

@Component
@Transactional
public class SysParamBusiness
{@Autowiredprivate SysParamDao sysParamDao;public void modify(SysParamMO mo) throws LittleCatException{sysParamDao.modify(mo);}public String getValueByName(String name) throws LittleCatException{return sysParamDao.getValueByName(name).getValue();}public List<SysParamMO> getList() throws LittleCatException{return sysParamDao.getList();}@Bean(name="SysParamBusiness") public SysParamBusiness getSysParamBusiness(){return new SysParamBusiness();}
}

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3、在我們自己的Util中使用

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public class SysParamUtil
{public static String PARAM_NAME_MEMBER_ENABLE_DAYS = "member_enable_days";private static final SysParamBusiness sysParamBusiness = (SysParamBusiness) SpringUtil.getBean("SysParamBusiness");public static String getValueByName(String name) throws LittleCatException{return sysParamBusiness.getValueByName(name);}
}

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注：

也可以這樣使用（如果沒有特殊邏輯，推薦使用這種方法）：

private static final SysParamBusiness sysParamBusiness = SpringUtil.getBean(SysParamBusiness.class);

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這樣，第二步就可以省略了。

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