如你希望Bean对象被创建过程中执行以下初始化动作，你可以通过实现InitializingBean接口或者使用@PostConstruct注解。
@Componentpublic class InitDataToRedis implements InitializingBean { public void afterPropertiesSet() throws Exception { }}
@Componentpublic class PersonService { @PostConstruct public void init() { }}
如希望在容器关闭时执行资源释放或者其它一些动作可以实现DisposableBean接口或者使用@PreDestroy注解。
public class Person implements DisposableBean { public void destroy() { }}@Componentpublic class PersonService { @PreDestroy public void destroy() { }}
@Component@Scope("prototype")public class PersonService {}@Controllerpublic class PersonController {}
如上如何在PersonController中注入PersonService呢？通过如下方法
@Lazyprivate PersonService personService ;
@Component@Scope(value = "prototype", proxyMode = ScopedProxyMode.TARGET_CLASS)public class PersonService {}
public class PersonController { @Resource private ApplicationContext context ; public Object index() { PersonService ps = this.context.getBean(PersonService.class) ; }}
如需要Bean在初始化前后执行相关的动作，可以通过实现该接口。
public class PackBeanPostProcessor implements BeanPostProcessor { @Override public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { } @Override public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { }}
4. BeanFactoryPostProcessor接口
如你希望在创建Bean对象之前修改BeanDefinition的相关属性可以通过实现该接口
public PackBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
@Override public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException { BeanDefinition definition = beanFactory.getBeanDefinition("person") ; definition.setScope("prototype") ; } }
如需要根据添加动态注册Bean，比如通过扫描包下的类符合条件的类注册为Bean对象，则可以通过如下的方式。
public class RepositoryBeanDefinitionRegister implements BeanDefinitionRegistryPostProcessor { @Override public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException { registry.registerBeanDefinition("person", BeanDefinitionBuilder.genericBeanDefinition(Person.class).getBeanDefinition()); }}
如需要在应用程序成功启动以后，执行一些任务，可以通过实现ApplicationRunner或者CommandLineRunner接口。
public class App implements CommandLineRunner { public void run(String... args) throws Exception { }}public class App implements ApplicationRunner { public void run(ApplicationArguments args) throws Exception { }}
当应用发生异常时可以通过注册全局异常处理，统一处理异常信息
@RestControllerAdvicepublic class GlobalControllerAdvice {
@ExceptionHandler({Exception.class}) public Object handle(Exception e) { // 其它处理 return R.failure(R.ResultCode.FAILURE, e.getMessage()) ; } }
public class CustomGenericConverter implements GenericConverter {
@Override public Set<ConvertiblePair> getConvertibleTypes() { ConvertiblePair teacherPair = new ConvertiblePair(String.class, Teacher.class) ; ConvertiblePair studentPair = new ConvertiblePair(String.class, Student.class) ; Set<ConvertiblePair> pairs = new HashSet<>() ; pairs.add(teacherPair) ; pairs.add(studentPair) ; return pairs ; }
@Override public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) { String str = null ; if (sourceType.getObjectType() == String.class) { str = (String) source ; } if (targetType.getObjectType() == Teacher.class) { String[] t = str.split("\\|") ; return new Teacher(t[0], Integer.valueOf(t[1])) ; } if (targetType.getObjectType() == Student.class) { String[] t = str.split("\\|") ; return new Student(t[0], t[1]) ; } return null ; }
}
@Componentpublic class WebConfig implements WebMvcConfigurer {
@Override public void addFormatters(FormatterRegistry registry) { registry.addConverter(new CustomGenericConverter()) ; } }
以上示例注册了一个，将字符串转换为Teacher和Student。
如果你希望在Bean中获取BeanFactory，可以通过实现BeanFactoryAware接口
@Servicepublic class PersonService implements BeanFactoryAware { private BeanFactory beanFactory;
@Override public void setBeanFactory(BeanFactory beanFactory) throws BeansException { this.beanFactory = beanFactory; }}
相关的*Aware接口，还有很多，如：ApplicationContextAware，ServletContextAware，BeanNameAware，EnvironmentAware等。
如你需要对某些接口进行鉴权或者其它一些处理，你可以注册自定义拦截器
@Componentpublic class WebConfig implements WebMvcConfigurer { @Override public void addInterceptors(InterceptorRegistry registry) { registry.addInterceptor(new HandlerInterceptor() { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out.println("preHandle method invoke...") ; return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { System.out.println("postHandle method invoke...") ; } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { System.out.println("afterCompletion method invoke...") ; } }).addPathPatterns("/**") ; } }}
BeanNameAutoProxyCreator
@Beanpublic BeanNameAutoProxyCreator beanNameAutoProxyCreator() { BeanNameAutoProxyCreator beanNameAutoProxyCreator = new BeanNameAutoProxyCreator(); beanNameAutoProxyCreator.setBeanNames("*Service") ; beanNameAutoProxyCreator.setInterceptorNames("tokenInterceptor"); return beanNameAutoProxyCreator ;}
上面的BeanNameAutoProxyCreator 是处理器类，只要beanName的后缀是Service结尾的都会被创建代理，然后通过以tokenInterceptor为beanName的拦截器增强。
以上是在SpringBoot项目开发中常用的一些技巧，希望本文对你有帮助。
