@Configuration+@Bean & @Component & @Resource/@autowired/@Inject

@Configuration+@Bean

示例代码：

@Configuration@ComponentScan(basePackages = WebConfig.PACKAGE_NAMESPACE)@EnableWebMvcpublic class WebConfig extends WebMvcConfigurerAdapter implements ApplicationContextAware {private ApplicationContext applicationContext;

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@Beanpublic CommonsMultipartResolver multipartResolver() {final CommonsMultipartResolver commonsMultipartResolver = new CommonsMultipartResolver();commonsMultipartResolver.setMaxUploadSize(MAX_UPLOAD_SIZE);return commonsMultipartResolver;}@Beanpublic TemplateEngine templateEngine() {final SpringTemplateEngine engine = new SpringTemplateEngine();engine.setEnableSpringELCompiler(true);engine.setTemplateResolver(this.templateResolver());return engine;}@Bean(name = "messageSource")public ReloadableResourceBundleMessageSource getMessageSource() {final ReloadableResourceBundleMessageSource resource = new ReloadableResourceBundleMessageSource();resource.setBasenames("classpath:i18n/application-messages");resource.setDefaultEncoding("UTF-8");return resource;}

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}

@Configuration相当于<beans>标签，所以此处WebConfig.class相当于一个xml配置文件而不是一个bean

@Bean相当于<bean>标签，但我的理解是，它所描述的bean只能是没有引入其他类的简单的bean

@Component

示例代码：

@Service@Transactionalpublic class XXServiceImpl implements XXService{@AutowiredTerminalRepository terminalRepository;@AutowiredProductRepository productRepository;...........

@Component(@Controller  @Service  @Repository) 也相当于<bean>标签，但我的理解是，他们所描述的不是像@Bean那样简单的bean

@Resource/@autowired/@Inject

前面的都是注入的注解，相当于“存”，而这三个就相当于“取”