org.springframework.context.annotation.Lazy#org.springframework.boot.autoconfigure.condition.ConditionalOnClass源码实例Demo

@Lazy
@Bean
@ConditionalOnMissingBean
@ConditionalOnClass(CamelContext.class)
public CamelReactiveStreamsService camelReactiveStreamsService(ApplicationContext ac) throws Exception {
    ReactiveStreamsEngineConfiguration engineConfiguration = new ReactiveStreamsEngineConfiguration();

    if (configuration.getReactiveStreamsEngineConfiguration() != null) {
        engineConfiguration = ac.getBean(configuration.getReactiveStreamsEngineConfiguration(), ReactiveStreamsEngineConfiguration.class);
    } else {
        engineConfiguration.setThreadPoolName(configuration.getThreadPoolName());
        if (configuration.getThreadPoolMinSize() != null) {
            engineConfiguration.setThreadPoolMinSize(configuration.getThreadPoolMinSize());
        }
        if (configuration.getThreadPoolMaxSize() != null) {
            engineConfiguration.setThreadPoolMinSize(configuration.getThreadPoolMaxSize());
        }
    }

    return ReactiveStreamsHelper.resolveReactiveStreamsService(context, configuration.getServiceType(), engineConfiguration);
}
 

/**
 * Build hibernate transaction manager.
 *
 * @param transactionManagerCustomizers transaction manager customizers
 * @return jpa transaction manager
 */
@Bean
@ConditionalOnMissingBean(PlatformTransactionManager.class)
@ConditionalOnClass(value = LocalContainerEntityManagerFactoryBean.class, name = "javax.persistence.EntityManager")
public PlatformTransactionManager jpaTransactionManager(final ObjectProvider<TransactionManagerCustomizers> transactionManagerCustomizers) {
    JpaTransactionManager result = new JpaTransactionManager();
    if (null != transactionManagerCustomizers.getIfAvailable()) {
        transactionManagerCustomizers.getIfAvailable().customize(result);
    }
    return result;
}
 

@Bean
@ConditionalOnClass(DefaultMQProducer.class)
@ConditionalOnMissingBean(DefaultMQProducer.class)
@ConditionalOnProperty(prefix = "spring.rocketmq", value = {"nameServer", "producer.group"})
public DefaultMQProducer mqProducer(RocketMQProperties rocketMQProperties) {

    RocketMQProperties.Producer producerConfig = rocketMQProperties.getProducer();
    String groupName = producerConfig.getGroup();
    Assert.hasText(groupName, "[spring.rocketmq.producer.group] must not be null");

    DefaultMQProducer producer = new DefaultMQProducer(producerConfig.getGroup());
    producer.setNamesrvAddr(rocketMQProperties.getNameServer());
    producer.setSendMsgTimeout(producerConfig.getSendMsgTimeout());
    producer.setRetryTimesWhenSendFailed(producerConfig.getRetryTimesWhenSendFailed());
    producer.setRetryTimesWhenSendAsyncFailed(producerConfig.getRetryTimesWhenSendAsyncFailed());
    producer.setMaxMessageSize(producerConfig.getMaxMessageSize());
    producer.setCompressMsgBodyOverHowmuch(producerConfig.getCompressMsgBodyOverHowmuch());
    producer.setRetryAnotherBrokerWhenNotStoreOK(producerConfig.isRetryAnotherBrokerWhenNotStoreOk());

    return producer;
}
 

/**
 * why use beanFactory to get DropWizardMetricsRegistry bean here?
 * because we do not want to import dropwizard dependencies indirectly!
 * let the application developer to decide whether or not to import.
 *
 * @return
 */
@Deprecated
@Bean
@ConditionalOnProperty(prefix = "com.alipay.sofa.lookout", name = "actuator-dropWizard-enabled", havingValue = "true", matchIfMissing = true)
@ConditionalOnClass(name = { "com.alipay.lookout.dropwizard.metrics.DropWizardMetricsRegistry",
        "com.codahale.metrics.MetricRegistry" })
public DropWizardMetricsRegistryFactory dropWizardMetricsRegistryFactory() {
    try {
        /*
         * In order to avoid [com.codahale.metrics.MetricRegistry] class not found.
         */
        com.codahale.metrics.MetricRegistry metricRegistry = beanFactory
            .getBean(com.codahale.metrics.MetricRegistry.class);
        if (metricRegistry == null) {
            logger
                .warn("spring boot actuator does not use dropwizard service,so lookout ignore dropwizard too!");
        } else {
            return new DropWizardMetricsRegistryFactory(metricRegistry);
        }
    } catch (NoClassDefFoundError e) {
        logger.debug("no dropwizard service found.");
    }
    return null;
}
 

@Bean
@ConditionalOnBean(GrayTrackFilter.class)
@ConditionalOnClass(FilterRegistrationBean.class)
public FilterRegistrationBean grayTraceFilter(GrayTrackFilter filter) {
    GrayTrackProperties.Web webProperties = grayTrackProperties.getWeb();
    FilterRegistrationBean registration = new FilterRegistrationBean();
    //注入过滤器
    registration.setFilter(filter);
    //拦截规则
    for (String pattern : webProperties.getPathPatterns()) {
        registration.addUrlPatterns(pattern);
    }
    //过滤器名称
    registration.setName("GrayTrackFilter");
    //过滤器顺序
    registration.setOrder(FilterRegistrationBean.LOWEST_PRECEDENCE);
    return registration;
}
 

@Bean
@ConditionalOnClass(FilterRegistrationBean.class)
@ConditionalOnMissingBean(RestDocConfig.HttpBasicAuth.class)
public FilterRegistrationBean<HttpBasicAuthFilter> swagger2HttpFilter(@Autowired(required = false) RestDocConfig restDocConfig) {
    RestDocConfig.HttpBasicAuth httpBasicAuth;
    if (restDocConfig == null || (httpBasicAuth = restDocConfig.getHttpBasicAuth()) == null)
        httpBasicAuth = new RestDocConfig.HttpBasicAuth(null, null);

    FilterRegistrationBean<HttpBasicAuthFilter> filterBean = new FilterRegistrationBean<>();
    HttpBasicAuthFilter authFilter = new HttpBasicAuthFilter(httpBasicAuth.getUsername(), httpBasicAuth.getPassword());
    filterBean.addUrlPatterns("/swagger2-ui/**","/swagger2.json","/swagger-ui/*","/swagger.json");
    filterBean.setFilter(authFilter);
    return filterBean;
}
 

@Bean
@ConditionalOnClass(DefaultMQProducer.class)
@ConditionalOnMissingBean(DefaultMQProducer.class)
public DefaultMQProducer mqProducer() {
    DefaultMQProducer producer = new DefaultMQProducer();
    producer.setProducerGroup(rocketMqProperties.getProducerGroupName());
    producer.setNamesrvAddr(rocketMqProperties.getNameServer());

    producer.setSendMsgTimeout(rocketMqProperties.getProducerSendMsgTimeout());
    producer.setRetryTimesWhenSendFailed(rocketMqProperties.getProducerRetryTimesWhenSendFailed());
    producer.setRetryTimesWhenSendAsyncFailed(rocketMqProperties.getProducerRetryTimesWhenSendAsyncFailed());
    producer.setMaxMessageSize(rocketMqProperties.getProducerMaxMessageSize());
    producer.setCompressMsgBodyOverHowmuch(rocketMqProperties.getProducerCompressMsgBodyOverHowMuch());
    producer.setRetryAnotherBrokerWhenNotStoreOK(rocketMqProperties.isProducerRetryAnotherBrokerWhenNotStoreOk());

    Runtime.getRuntime().addShutdownHook(new Thread(() -> {
        LOGGER.info("producer shutdown");
        producer.shutdown();
        LOGGER.info("producer has shutdown");
    }));

    try {
        producer.start();
        LOGGER.info("rocketmq producer started, nameserver:{}, group:{}", rocketMqProperties.getNameServer(),
                rocketMqProperties.getProducerGroupName());
    } catch (MQClientException e) {
        LOGGER.error("producer start error, nameserver:{}, group:{}", rocketMqProperties.getNameServer(),
                rocketMqProperties.getProducerGroupName(), e);
    }

    return producer;
}
 

/**
 * Creates a GrpcServerFactory using the non-shaded netty. This is the fallback, if the shaded one is not present.
 *
 * @param properties The properties used to configure the server.
 * @param serviceDiscoverer The discoverer used to identify the services that should be served.
 * @param serverConfigurers The server configurers that contain additional configuration for the server.
 * @return The shadedNettyGrpcServerFactory bean.
 */
@ConditionalOnMissingBean(ShadedNettyGrpcServerFactory.class)
@Conditional(ConditionalOnInterprocessServer.class)
@ConditionalOnClass(name = {"io.netty.channel.Channel", "io.grpc.netty.NettyServerBuilder"})
@Bean
public NettyGrpcServerFactory nettyGrpcServerFactory(final GrpcServerProperties properties,
        final GrpcServiceDiscoverer serviceDiscoverer, final List<GrpcServerConfigurer> serverConfigurers) {
    final NettyGrpcServerFactory factory = new NettyGrpcServerFactory(properties, serverConfigurers);
    for (final GrpcServiceDefinition service : serviceDiscoverer.findGrpcServices()) {
        factory.addService(service);
    }
    return factory;
}
 

@Lazy
@Bean(name = "dns-service-discovery")
@ConditionalOnClass(CamelContext.class)
public ServiceDiscovery configureServiceDiscoveryFactory() throws Exception {
    DnsServiceDiscoveryFactory factory = new DnsServiceDiscoveryFactory();

    IntrospectionSupport.setProperties(
        camelContext,
        camelContext.getTypeConverter(),
        factory,
        IntrospectionSupport.getNonNullProperties(configuration));

    return factory.newInstance(camelContext);
}
 

@Bean(name = HystrixConstants.DEFAULT_HYSTRIX_CONFIGURATION_ID)
@ConditionalOnClass(CamelContext.class)
@ConditionalOnMissingBean(name = HystrixConstants.DEFAULT_HYSTRIX_CONFIGURATION_ID)
public HystrixConfigurationDefinition defaultHystrixConfigurationDefinition() throws Exception {
    Map<String, Object> properties = new HashMap<>();

    IntrospectionSupport.getProperties(config, properties, null, false);
    HystrixConfigurationDefinition definition = new HystrixConfigurationDefinition();
    IntrospectionSupport.setProperties(camelContext, camelContext.getTypeConverter(), definition, properties);

    return definition;
}
 

@Bean(name = ResilienceConstants.DEFAULT_RESILIENCE_CONFIGURATION_ID)
@ConditionalOnClass(CamelContext.class)
@ConditionalOnMissingBean(name = ResilienceConstants.DEFAULT_RESILIENCE_CONFIGURATION_ID)
public Resilience4jConfigurationDefinition defaultResilienceConfigurationDefinition() throws Exception {
    Map<String, Object> properties = new HashMap<>();

    IntrospectionSupport.getProperties(config, properties, null, false);
    Resilience4jConfigurationDefinition definition = new Resilience4jConfigurationDefinition();
    IntrospectionSupport.setProperties(camelContext, camelContext.getTypeConverter(), definition, properties);

    return definition;
}
 

@Lazy
@Bean(name = "ribbon-load-balancer")
@ConditionalOnClass(CamelContext.class)
public ServiceLoadBalancer configureLoadBalancerFactory() throws Exception {
    RibbonServiceLoadBalancerFactory factory = new RibbonServiceLoadBalancerFactory();

    IntrospectionSupport.setProperties(
        camelContext,
        camelContext.getTypeConverter(),
        factory,
        IntrospectionSupport.getNonNullProperties(configuration));

    return factory.newInstance(camelContext);
}
 

@ConditionalOnProperty(name = BASE_PACKAGES_PROPERTY_NAME)
@ConditionalOnClass(ConfigurationPropertySources.class)
@Bean
public FeignClientToDubboProviderBeanPostProcessor feignClientToDubboProviderBeanPostProcessor(Environment environment) {
    Set<String> packagesToScan = environment.getProperty(BASE_PACKAGES_PROPERTY_NAME, Set.class, emptySet());
    return new FeignClientToDubboProviderBeanPostProcessor(packagesToScan);
}
 

/**
 * 自定义网关监控端点
 *
 * @param context
 * @param bus
 * @return
 */
@Bean
@ConditionalOnEnabledEndpoint
@ConditionalOnClass({Endpoint.class})
public ApiEndpoint apiEndpoint(ApplicationContext context, BusProperties bus) {
    ApiEndpoint endpoint = new ApiEndpoint(context, bus.getId());
    log.info("ApiEndpoint [{}]", endpoint);
    return endpoint;
}
 

/**
 * 网关bus端点
 *
 * @param context
 * @param bus
 * @return
 */
@Bean
@ConditionalOnEnabledEndpoint
@ConditionalOnClass({Endpoint.class})
public ApiEndpoint apiEndpoint(ApplicationContext context, BusProperties bus) {
    ApiEndpoint endpoint = new ApiEndpoint(context, bus.getId());
    log.info("ApiEndpoint [{}]", endpoint);
    return endpoint;
}
 

@Bean
@ConditionalOnClass({ AliyunSmsSenderImpl.class })
public SmsSender smsSender(AliyunSmsProperties aliyunSmsProperties) {
       AliyunSmsSenderImpl sender = new AliyunSmsSenderImpl();
	BeanUtils.copyProperties(aliyunSmsProperties, sender);
	return sender;
}
 

/**
 * Springdoc bean factory post processor bean factory post processor.
 *
 * @return the bean factory post processor
 */
@Bean
@Conditional(CacheOrGroupedOpenApiCondition.class)
@ConditionalOnClass(name = BINDRESULT_CLASS)
@Lazy(false)
static BeanFactoryPostProcessor springdocBeanFactoryPostProcessor() {
	return new SpringdocBeanFactoryConfigurer();
}
 

@Bean
@ConditionalOnClass({AliyunSmsSender.class})
@ConditionalOnProperty(name = "spring.notify.sms.aliyun.accessKeyId")
public SmsSender smsSender() {
	AliyunSmsSender sender = new AliyunSmsSender();
	BeanUtils.copyProperties(aliyunSmsProperties, sender);
	return sender;
}
 

@Bean
@RxMVC
@ConditionalOnMissingBean
@ConditionalOnClass(Observable.class)
public ObservableReturnValueHandler observableReturnValueHandler() {
    return new ObservableReturnValueHandler();
}
 

@Bean
@RxMVC
@ConditionalOnMissingBean
@ConditionalOnClass(Single.class)
public SingleReturnValueHandler singleReturnValueHandler() {
    return new SingleReturnValueHandler();
}
 

/**
 * Build hibernate transaction manager.
 *
 * @param transactionManagerCustomizers transaction manager customizers
 * @return jpa transaction manager
 */
@Bean
@ConditionalOnMissingBean(PlatformTransactionManager.class)
@ConditionalOnClass(value = LocalContainerEntityManagerFactoryBean.class, name = "javax.persistence.EntityManager")
public PlatformTransactionManager jpaTransactionManager(final ObjectProvider<TransactionManagerCustomizers> transactionManagerCustomizers) {
    JpaTransactionManager result = new JpaTransactionManager();
    if (null != transactionManagerCustomizers.getIfAvailable()) {
        transactionManagerCustomizers.getIfAvailable().customize(result);
    }
    return result;
}
 

@ConditionalOnMissingBean(GrpcChannelFactory.class)
@ConditionalOnClass(name = {"io.grpc.netty.shaded.io.netty.channel.Channel",
        "io.grpc.netty.shaded.io.grpc.netty.NettyChannelBuilder"})
@Bean
@Lazy
GrpcChannelFactory shadedNettyGrpcChannelFactory(final GrpcChannelsProperties properties,
        final GlobalClientInterceptorRegistry globalClientInterceptorRegistry,
        final List<GrpcChannelConfigurer> channelConfigurers) {
    final ShadedNettyChannelFactory channelFactory =
            new ShadedNettyChannelFactory(properties, globalClientInterceptorRegistry, channelConfigurers);
    final InProcessChannelFactory inProcessChannelFactory =
            new InProcessChannelFactory(properties, globalClientInterceptorRegistry, channelConfigurers);
    return new InProcessOrAlternativeChannelFactory(properties, inProcessChannelFactory, channelFactory);
}
 

@Bean
@ConditionalOnProperty(prefix = "quickfixj.client", name = "jmx-enabled", havingValue = "true")
@ConditionalOnClass(JmxExporter.class)
@ConditionalOnSingleCandidate(Initiator.class)
@ConditionalOnMissingBean(name = "clientInitiatorMBean", value = ObjectName.class)
public ObjectName clientInitiatorMBean(Initiator clientInitiator) {
	try {
		JmxExporter exporter = new JmxExporter();
		exporter.setRegistrationBehavior(REGISTRATION_REPLACE_EXISTING);
		return exporter.register(clientInitiator);
	} catch (Exception e) {
		throw new ConfigurationException(e.getMessage(), e);
	}
}
 

/**
 * JSON 格式 {@link Formatter} Bean
 *
 * @return {@link JsonFormatter}
 */
@Bean
@ConditionalOnClass(name = "com.fasterxml.jackson.databind.ObjectMapper")
@ConditionalOnMissingBean(type = "com.fasterxml.jackson.databind.ObjectMapper")
public Formatter jsonFormatter() {
    return new JsonFormatter();
}
 

/**
 * Create a {@code ReactiveClientRegistrationRepository} bean for use with an
 * OAuth2-enabled {@code ReactiveCredHubTemplate}, in case
 * {@link ReactiveOAuth2ClientAutoConfiguration} doesn't configure one.
 * @return the {@code ReactiveClientRegistrationRepository}
 */
@Bean
@ConditionalOnMissingBean
@ConditionalOnClass(name = "org.springframework.web.reactive.function.client.WebClient")
public ReactiveClientRegistrationRepository credHubReactiveClientRegistrationRepository() {
	List<ClientRegistration> registrations = new ArrayList<>(
			OAuth2ClientPropertiesRegistrationAdapter.getClientRegistrations(this.properties).values());
	return new InMemoryReactiveClientRegistrationRepository(registrations);
}
 

@Bean
@Scope("prototype")
@ConditionalOnClass(name = { "com.netflix.hystrix.HystrixCommand", "feign.hystrix.HystrixFeign" })
@ConditionalOnProperty(name = "feign.hystrix.enabled", havingValue = "true")
Feign.Builder feignHystrixBuilder() {
    return SofaTracerHystrixFeignBuilder.builder();
}
 

@ConditionalOnMissingBean(GrpcChannelFactory.class)
@ConditionalOnClass(name = {"io.netty.channel.Channel", "io.grpc.netty.NettyChannelBuilder"})
@Bean
@Lazy
GrpcChannelFactory nettyGrpcChannelFactory(final GrpcChannelsProperties properties,
        final GlobalClientInterceptorRegistry globalClientInterceptorRegistry,
        final List<GrpcChannelConfigurer> channelConfigurers) {
    final NettyChannelFactory channelFactory =
            new NettyChannelFactory(properties, globalClientInterceptorRegistry, channelConfigurers);
    final InProcessChannelFactory inProcessChannelFactory =
            new InProcessChannelFactory(properties, globalClientInterceptorRegistry, channelConfigurers);
    return new InProcessOrAlternativeChannelFactory(properties, inProcessChannelFactory, channelFactory);
}
 

/**
 * Creates a GrpcServerFactory using the shaded netty. This is the recommended default for gRPC.
 *
 * @param properties The properties used to configure the server.
 * @param serviceDiscoverer The discoverer used to identify the services that should be served.
 * @param serverConfigurers The server configurers that contain additional configuration for the server.
 * @return The shadedNettyGrpcServerFactory bean.
 */
@ConditionalOnClass(name = {"io.grpc.netty.shaded.io.netty.channel.Channel",
        "io.grpc.netty.shaded.io.grpc.netty.NettyServerBuilder"})
@Conditional(ConditionalOnInterprocessServer.class)
@Bean
public ShadedNettyGrpcServerFactory shadedNettyGrpcServerFactory(final GrpcServerProperties properties,
        final GrpcServiceDiscoverer serviceDiscoverer, final List<GrpcServerConfigurer> serverConfigurers) {
    final ShadedNettyGrpcServerFactory factory = new ShadedNettyGrpcServerFactory(properties, serverConfigurers);
    for (final GrpcServiceDefinition service : serviceDiscoverer.findGrpcServices()) {
        factory.addService(service);
    }
    return factory;
}
 

@ConditionalOnProperty(name = BASE_PACKAGES_PROPERTY_NAME)
@ConditionalOnClass(ConfigurationPropertySources.class)
@Bean
public FeignClientToDubboProviderBeanPostProcessor feignClientToDubboProviderBeanPostProcessor(Environment environment) {
    Set<String> packagesToScan = environment.getProperty(BASE_PACKAGES_PROPERTY_NAME, Set.class, emptySet());
    return new FeignClientToDubboProviderBeanPostProcessor(packagesToScan);
}
 

/**
 * It is used to register the tomcat valve with the tomcat container.
 * 
 * @return embeddedTomcat
 */
@Bean
@ConditionalOnClass({ Servlet.class, Tomcat.class })
public ServletWebServerFactory servletContainerWithSemaphoreRateLimiterValve() {
	TomcatServletWebServerFactory embeddedTomcat = new TomcatServletWebServerFactory();
	embeddedTomcat.addEngineValves(new ProductShedLoadSemaphoreValve(shedLoad));
	return embeddedTomcat;
}