深入理解SpringCloud之DiscoveryClient探究 |
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深入理解SpringCloud之DiscoveryClient探究
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当我们使用@DiscoveryClient注解的时候，会不会有如下疑问：它为什么会进行注册服务的操作，它不是应该用作服务发现的吗？下面我们就来深入的探究一下其源码。 一、Springframework的LifeCycle接口要搞明白这个问题我们需要了解一下这个重要的接口：  
/*
* Copyright 2002-2015 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.context;
/**
* A common interface defining methods for start/stop lifecycle control.
* The typical use case for this is to control asynchronous processing.
* NOTE: This interface does not imply specific auto-startup semantics.
* Consider implementing {@link SmartLifecycle} for that purpose.
*
* Can be implemented by both components (typically a Spring bean defined in a * Spring context) and containers (typically a Spring {@link ApplicationContext} * itself). Containers will propagate start/stop signals to all components that * apply within each container, e.g. for a stop/restart scenario at runtime. * * Can be used for direct invocations or for management operations via JMX. * In the latter case, the {@link org.springframework.jmx.export.MBeanExporter} * will typically be defined with an * {@link org.springframework.jmx.export.assembler.InterfaceBasedMBeanInfoAssembler}, * restricting the visibility of activity-controlled components to the Lifecycle * interface. * * Note that the Lifecycle interface is only supported on top-level singleton * beans. On any other component, the Lifecycle interface will remain undetected * and hence ignored. Also, note that the extended {@link SmartLifecycle} interface * provides integration with the application context's startup and shutdown phases. * * @author Juergen Hoeller * @since 2.0 * @see SmartLifecycle * @see ConfigurableApplicationContext * @see org.springframework.jms.listener.AbstractMessageListenerContainer * @see org.springframework.scheduling.quartz.SchedulerFactoryBean */ public interface Lifecycle { /** * Start this component. * Should not throw an exception if the component is already running. * In the case of a container, this will propagate the start signal to all * components that apply. * @see SmartLifecycle#isAutoStartup() */ void start(); /** * Stop this component, typically in a synchronous fashion, such that the component is * fully stopped upon return of this method. Consider implementing {@link SmartLifecycle} * and its {@code stop(Runnable)} variant when asynchronous stop behavior is necessary. * Note that this stop notification is not guaranteed to come before destruction: On * regular shutdown, {@code Lifecycle} beans will first receive a stop notification before * the general destruction callbacks are being propagated; however, on hot refresh during a * context's lifetime or on aborted refresh attempts, only destroy methods will be called. * Should not throw an exception if the component isn't started yet. * In the case of a container, this will propagate the stop signal to all components * that apply. * @see SmartLifecycle#stop(Runnable) * @see org.springframework.beans.factory.DisposableBean#destroy() */ void stop(); /** * Check whether this component is currently running. * In the case of a container, this will return {@code true} only if all * components that apply are currently running. * @return whether the component is currently running */ boolean isRunning(); } View Code 该接口定义启动/停止生命周期控制方法，当spring ioc容器启动或停止时将发送一个启动或者停止的信号通知到各个组件，因此我们可以在对应的方法里做我们想要的事情。我们可以通过类图发现我们常用的ClasspathXmlApplicationContext类就实现了该接口
下面我们来简单演示一下案例，创建类MyLifeCycle：
package org.hzgj.spring.study.context;
import org.springframework.context.SmartLifecycle;
public class MyLifeCycle implements SmartLifecycle {
@Override
public void start() {
System.out.println("MyLifeCycle start ....");
}
@Override
public void stop() {
System.out.println("MyLifeCycle stop .....");
}
@Override
public boolean isRunning() {
return false;
}
@Override
public boolean isAutoStartup() {
return true;
}
@Override
public void stop(Runnable callback) {
}
@Override
public int getPhase() {
System.out.println("phase");
return 10;
}
}
View Code
在这里我们继承SmartLifeCycle该接口继承了LifeCycle, isRunning方法用于检测当前的组件是否处在运行状态，注意只有当isRunning返回值为false才可以运行 我们把MyLifeCycle配置到spring配置文件里，通过ClassPathXmlApplicationContext运行 会得到如下结果：
另外在这里的getPhase方法，这个是定义阶段值（可以理解为优先级，值越小对应的LifeCycle越先执行） 二、DiscoveryClient源码探究 @EnableDiscoveyClient
/*
* Copyright 2013-2015 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.cloud.client.discovery;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.springframework.context.annotation.Import;
/**
* Annotation to enable a DiscoveryClient implementation.
* @author Spencer Gibb
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@Import(EnableDiscoveryClientImportSelector.class)
public @interface EnableDiscoveryClient {
/**
* If true, the ServiceRegistry will automatically register the local server.
*/
boolean autoRegister() default true;
}
View Code
请注意 @Import(EnableDiscoveryClientImportSelector.class) 我们可以参考一下这个类：
/*
* Copyright 2013-2015 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.cloud.client.discovery;
import org.springframework.boot.bind.RelaxedPropertyResolver;
import org.springframework.cloud.commons.util.SpringFactoryImportSelector;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.AnnotationAttributes;
import org.springframework.core.annotation.Order;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.Environment;
import org.springframework.core.env.MapPropertySource;
import org.springframework.core.type.AnnotationMetadata;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedHashMap;
import java.util.List;
/**
* @author Spencer Gibb
*/
@Order(Ordered.LOWEST_PRECEDENCE - 100)
public class EnableDiscoveryClientImportSelector
extends SpringFactoryImportSelector {
@Override
public String[] selectImports(AnnotationMetadata metadata) {
String[] imports = super.selectImports(metadata);
AnnotationAttributes attributes = AnnotationAttributes.fromMap(
metadata.getAnnotationAttributes(getAnnotationClass().getName(), true));
boolean autoRegister = attributes.getBoolean("autoRegister");
if (autoRegister) {
List importsList = new ArrayList(Arrays.asList(imports));
importsList.add("org.springframework.cloud.client.serviceregistry.AutoServiceRegistrationConfiguration");
imports = importsList.toArray(new String[0]);
} else {
Environment env = getEnvironment();
if(ConfigurableEnvironment.class.isInstance(env)) {
ConfigurableEnvironment configEnv = (ConfigurableEnvironment)env;
LinkedHashMap map = new LinkedHashMap();
map.put("spring.cloud.service-registry.auto-registration.enabled", false);
MapPropertySource propertySource = new MapPropertySource(
"springCloudDiscoveryClient", map);
configEnv.getPropertySources().addLast(propertySource);
}
}
return imports;
}
@Override
protected boolean isEnabled() {
return new RelaxedPropertyResolver(getEnvironment()).getProperty(
"spring.cloud.discovery.enabled", Boolean.class, Boolean.TRUE);
}
@Override
protected boolean hasDefaultFactory() {
return true;
}
}
View Code
这个类重写的方法来自于接口 ImportSelector，我们可以根据 if(autoRegister)下的代码追踪到类：org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration，我们来看一下结构图：
我们可以得知这个类实现了Lifecycle接口，那么我们看一看start方法，此方法在它的父类AbstractDiscoveryLifecycle里：
/*
* Copyright 2013-2015 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.cloud.client.discovery;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import javax.annotation.PreDestroy;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeansException;
import org.springframework.boot.context.embedded.EmbeddedServletContainerInitializedEvent;
import org.springframework.cloud.client.discovery.event.InstanceRegisteredEvent;
import org.springframework.cloud.client.serviceregistry.ServiceRegistry;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationListener;
import org.springframework.core.env.Environment;
/**
* Lifecycle methods that may be useful and common to various DiscoveryClient implementations.
*
* @deprecated use {@link org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration} instead. This class will be removed in the next release train.
*
* @author Spencer Gibb
*/
@Deprecated
public abstract class AbstractDiscoveryLifecycle implements DiscoveryLifecycle,
ApplicationContextAware, ApplicationListener {
private static final Log logger = LogFactory.getLog(AbstractDiscoveryLifecycle.class);
private boolean autoStartup = true;
private AtomicBoolean running = new AtomicBoolean(false);
private int order = 0;
private ApplicationContext context;
private Environment environment;
private AtomicInteger port = new AtomicInteger(0);
protected ApplicationContext getContext() {
return context;
}
@Override
public void setApplicationContext(ApplicationContext applicationContext)
throws BeansException {
this.context = applicationContext;
this.environment = this.context.getEnvironment();
}
@Deprecated
protected Environment getEnvironment() {
return environment;
}
@Deprecated
protected AtomicInteger getPort() {
return port;
}
@Override
public boolean isAutoStartup() {
return this.autoStartup;
}
@Override
public void stop(Runnable callback) {
try {
stop();
} catch (Exception e) {
logger.error("A problem occurred attempting to stop discovery lifecycle", e);
}
callback.run();
}
@Override
public void start() {
if (!isEnabled()) {
if (logger.isDebugEnabled()) {
logger.debug("Discovery Lifecycle disabled. Not starting");
}
return;
}
// only set the port if the nonSecurePort is 0 and this.port != 0
if (this.port.get() != 0 && getConfiguredPort() == 0) {
setConfiguredPort(this.port.get());
}
// only initialize if nonSecurePort is greater than 0 and it isn't already running
// because of containerPortInitializer below
if (!this.running.get() && getConfiguredPort() > 0) {
register();
if (shouldRegisterManagement()) {
registerManagement();
}
this.context.publishEvent(new InstanceRegisteredEvent(this,
getConfiguration()));
this.running.compareAndSet(false, true);
}
}
@Deprecated
protected abstract int getConfiguredPort();
@Deprecated
protected abstract void setConfiguredPort(int port);
/**
* @return if the management service should be registered with the {@link ServiceRegistry}
*/
protected boolean shouldRegisterManagement() {
return getManagementPort() != null && ManagementServerPortUtils.isDifferent(this.context);
}
/**
* @return the object used to configure the registration
*/
@Deprecated
protected abstract Object getConfiguration();
/**
* Register the local service with the DiscoveryClient
*/
protected abstract void register();
/**
* Register the local management service with the DiscoveryClient
*/
protected void registerManagement() {
}
/**
* De-register the local service with the DiscoveryClient
*/
protected abstract void deregister();
/**
* De-register the local management service with the DiscoveryClient
*/
protected void deregisterManagement() {
}
/**
* @return true, if the {@link DiscoveryLifecycle} is enabled
*/
protected abstract boolean isEnabled();
/**
* @return the serviceId of the Management Service
*/
@Deprecated
protected String getManagementServiceId() {
// TODO: configurable management suffix
return this.context.getId() + ":management";
}
/**
* @return the service name of the Management Service
*/
@Deprecated
protected String getManagementServiceName() {
// TODO: configurable management suffix
return getAppName() + ":management";
}
/**
* @return the management server port
*/
@Deprecated
protected Integer getManagementPort() {
return ManagementServerPortUtils.getPort(this.context);
}
/**
* @return the app name, currently the spring.application.name property
*/
@Deprecated
protected String getAppName() {
return this.environment.getProperty("spring.application.name", "application");
}
@Override
public void stop() {
if (this.running.compareAndSet(true, false) && isEnabled()) {
deregister();
if (shouldRegisterManagement()) {
deregisterManagement();
}
}
}
@PreDestroy
public void destroy() {
stop();
}
@Override
public boolean isRunning() {
return this.running.get();
}
protected AtomicBoolean getRunning() {
return running;
}
@Override
public int getOrder() {
return this.order;
}
@Override
public int getPhase() {
return 0;
}
@Override
@Deprecated
public void onApplicationEvent(EmbeddedServletContainerInitializedEvent event) {
// TODO: take SSL into account
// Don't register the management port as THE port
if (!"management".equals(event.getApplicationContext().getNamespace())) {
this.port.compareAndSet(0, event.getEmbeddedServletContainer().getPort());
this.start();
}
}
}
View Code
注意在start方法里有一段这个代码： if (!this.running.get() && getConfiguredPort() > 0) { register(); if (shouldRegisterManagement()) { registerManagement(); } this.context.publishEvent(new InstanceRegisteredEvent(this, getConfiguration())); this.running.compareAndSet(false, true); }请注意register() 这个方法是本类里的抽象方法。那么我们回过头看一下AbstractAutoServiceRegistration类里的代码，我这里只贴出关键部分：
//.....
protected AbstractAutoServiceRegistration(ServiceRegistry serviceRegistry, AutoServiceRegistrationProperties properties) {
this.serviceRegistry = serviceRegistry;
this.properties = properties;
}
//......
/**
* Register the local service with the {@link ServiceRegistry}
*/
@Override
protected void register() {
this.serviceRegistry.register(getRegistration());
}
View Code
我们可以发现在构造函数里传了一个ServiceRegistry类型，这个接口是SpringCloud给我们提供用于服务注册的接口。在这里EurekaServiceRegistry就是实现了此接口：
/*
* Copyright 2013-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.springframework.cloud.netflix.eureka.serviceregistry;
import java.util.HashMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.cloud.client.serviceregistry.ServiceRegistry;
import com.netflix.appinfo.InstanceInfo;
/**
* @author Spencer Gibb
*/
public class EurekaServiceRegistry implements ServiceRegistry {
private static final Log log = LogFactory.getLog(EurekaServiceRegistry.class);
@Override
public void register(EurekaRegistration reg) {
maybeInitializeClient(reg);
if (log.isInfoEnabled()) {
log.info("Registering application " + reg.getInstanceConfig().getAppname()
+ " with eureka with status "
+ reg.getInstanceConfig().getInitialStatus());
}
reg.getApplicationInfoManager()
.setInstanceStatus(reg.getInstanceConfig().getInitialStatus());
if (reg.getHealthCheckHandler() != null) {
reg.getEurekaClient().registerHealthCheck(reg.getHealthCheckHandler());
}
}
private void maybeInitializeClient(EurekaRegistration reg) {
// force initialization of possibly scoped proxies
reg.getApplicationInfoManager().getInfo();
reg.getEurekaClient().getApplications();
}
@Override
public void deregister(EurekaRegistration reg) {
if (reg.getApplicationInfoManager().getInfo() != null) {
if (log.isInfoEnabled()) {
log.info("Unregistering application " + reg.getInstanceConfig().getAppname()
+ " with eureka with status DOWN");
}
reg.getApplicationInfoManager().setInstanceStatus(InstanceInfo.InstanceStatus.DOWN);
//shutdown of eureka client should happen with EurekaRegistration.close()
//auto registration will create a bean which will be properly disposed
//manual registrations will need to call close()
}
}
@Override
public void setStatus(EurekaRegistration registration, String status) {
InstanceInfo info = registration.getApplicationInfoManager().getInfo();
//TODO: howto deal with delete properly?
if ("CANCEL_OVERRIDE".equalsIgnoreCase(status)) {
registration.getEurekaClient().cancelOverrideStatus(info);
return;
}
//TODO: howto deal with status types across discovery systems?
InstanceInfo.InstanceStatus newStatus = InstanceInfo.InstanceStatus.toEnum(status);
registration.getEurekaClient().setStatus(newStatus, info);
}
@Override
public Object getStatus(EurekaRegistration registration) {
HashMap status = new HashMap();
InstanceInfo info = registration.getApplicationInfoManager().getInfo();
status.put("status", info.getStatus().toString());
status.put("overriddenStatus", info.getOverriddenStatus().toString());
return status;
}
public void close() {
}
}
View Code
那么至此我们可以总结如下几点： 1、使用@DiscoveryClient注册服务是利用了LifeCycle机制，在容器启动时会执行ServiceRegistry的register()方法。 2、使用@DiscoveryClient要比@EnableEurekaClient与@EnableEurekaServer更灵活，因为它屏蔽了对服务注册的实现，我们甚至可以自定义注册中心。 3、它还会自动去寻找DiscoveryClient接口的实现用作服务发现 三、Discoveryclient实战之redis注册中心 下面我们实现一个基于redis为注册中心的需求，来理解一下Discoveryclient。顺便理解一下Springcloud重要的接口：ServiceRegistry,ServiceInstance，再此之前我们先添加对redis的支持： compile group: 'org.springframework.boot', name: 'spring-boot-starter-data-redis' 1、实现Registration接口
package com.hzgj.lyrk.member;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.client.serviceregistry.Registration;
import org.springframework.stereotype.Component;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.URI;
import java.util.Enumeration;
import java.util.Map;
@Component
public class RedisRegistration implements Registration {
@Value("${server.port}")
private Integer port;
@Value("${spring.application.name}")
private String applicationName;
private String host;
public void setHost(String host) {
this.host = host;
}
public void setPort(Integer port) {
this.port = port;
}
public void setApplicationName(String applicationName) {
this.applicationName = applicationName;
}
@Override
public String getServiceId() {
return applicationName + ":" + getHost() + ":" + getPort();
}
@Override
public String getHost() {
try {
if (host == null)
return getLocalHostLANAddress().getHostAddress();
else
return host;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
public int getPort() {
return port;
}
@Override
public boolean isSecure() {
return false;
}
@Override
public URI getUri() {
return null;
}
@Override
public Map getMetadata() {
return null;
}
public String getServiceName() {
return this.applicationName;
}
public InetAddress getLocalHostLANAddress() throws Exception {
try {
InetAddress candidateAddress = null;
// 遍历所有的网络接口
for (Enumeration ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements(); ) {
NetworkInterface iface = (NetworkInterface) ifaces.nextElement();
// 在所有的接口下再遍历IP
for (Enumeration inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements(); ) {
InetAddress inetAddr = (InetAddress) inetAddrs.nextElement();
if (!inetAddr.isLoopbackAddress()) {// 排除loopback类型地址
if (inetAddr.isSiteLocalAddress()) {
// 如果是site-local地址，就是它了
return inetAddr;
} else if (candidateAddress == null) {
// site-local类型的地址未被发现，先记录候选地址
candidateAddress = inetAddr;
}
}
}
}
if (candidateAddress != null) {
return candidateAddress;
}
// 如果没有发现 non-loopback地址.只能用最次选的方案
InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
return jdkSuppliedAddress;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
View Code
该接口继承了ServiceIntance,那么此接口最主要作用就是定义了一个服务实例的规范，比如说它的serviceId是什么，端口号是什么等 2、实现ServiceRegistry的接口
package com.hzgj.lyrk.member;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.serviceregistry.ServiceRegistry;
import org.springframework.data.redis.core.StringRedisTemplate;
public class RedisServiceRegistry implements ServiceRegistry {
@Autowired
private StringRedisTemplate redisTemplate;
@Override
public void register(RedisRegistration registration) {
String serviceId = registration.getServiceId();
redisTemplate.opsForList().leftPush(serviceId, registration.getHost() + ":" + registration.getPort());
}
@Override
public void deregister(RedisRegistration registration) {
redisTemplate.opsForList().remove(registration.getServiceId(), 1, registration.getHost() + ":" + registration.getPort());
}
@Override
public void close() {
//redisTemplate.d
System.out.println("closed ...");
}
@Override
public void setStatus(RedisRegistration registration, String status) {
}
@Override
public T getStatus(RedisRegistration registration) {
return null;
}
}
View Code
该接口主要作用是定义如何进行服务注册 ，服务注销，设置与获取服务状态等操作 3、继承 AbstractAutoServiceRegistration抽象类
package com.hzgj.lyrk.member;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration;
import org.springframework.cloud.client.serviceregistry.AutoServiceRegistrationProperties;
import org.springframework.cloud.client.serviceregistry.ServiceRegistry;
public class RedisAutoServiceRegistration extends AbstractAutoServiceRegistration {
@Autowired
private RedisRegistration redisRegistration;
protected RedisAutoServiceRegistration(ServiceRegistry serviceRegistry, AutoServiceRegistrationProperties properties) {
super(serviceRegistry, properties);
// serviceRegistry.register(getRegistration());
}
@Override
protected int getConfiguredPort() {
return redisRegistration.getPort();
}
@Override
protected void setConfiguredPort(int port) {
}
@Override
protected Object getConfiguration() {
return null;
}
@Override
protected boolean isEnabled() {
return true;
}
@Override
protected RedisRegistration getRegistration() {
return redisRegistration;
}
@Override
protected RedisRegistration getManagementRegistration() {
return null;
}
}
View Code
4、定义DiscoveryClient的实现类RedisDiscoveryClient
package com.hzgj.lyrk.member;
import org.apache.commons.lang.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.data.redis.core.StringRedisTemplate;
import java.util.ArrayList;
import java.util.List;
import java.util.function.Function;
import java.util.stream.Collectors;
public class RedisDiscoveryClient implements DiscoveryClient {
@Autowired
private StringRedisTemplate redisTemplate;
@Override
public String description() {
return "redis注册中心的服务发现";
}
@Override
public ServiceInstance getLocalServiceInstance() {
return null;
}
@Override
public List getInstances(String serviceId) {
return redisTemplate.opsForList().range(serviceId, 0, -1).
parallelStream().map((Function) s -> {
RedisRegistration redisRegistration = new RedisRegistration();
redisRegistration.setApplicationName(serviceId);
String hostName = StringUtils.split(s, ":")[0];
String port = StringUtils.split(s, ":")[1];
redisRegistration.setHost(hostName);
redisRegistration.setPort(Integer.parseInt(port));
//redisRegistration
return redisRegistration;
}).collect(Collectors.toList());
}
@Override
public List getServices() {
List list = new ArrayList();
list.addAll(redisTemplate.keys("*"));
return list;
}
}
View Code
该类主要是针对于redis注册中心的服务发现 5、定义自动装配的类用以创建对应的bean
package com.hzgj.lyrk.member;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.cloud.client.serviceregistry.AutoServiceRegistrationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
@Configuration
@EnableConfigurationProperties(RedisConfig.class)
@ConditionalOnProperty(value = "spring.redis.registry.enabled", matchIfMissing = true)
public class RedisRegistryAutoConfiguration {
@Bean
RedisServiceRegistry redisServiceRegistry(RedisConfig redisConfig) {
System.out.println(redisConfig.getHost());
return new RedisServiceRegistry();
}
@Bean
RedisAutoServiceRegistration redisAutoServiceRegistration(RedisServiceRegistry redisServiceRegistry) {
return new RedisAutoServiceRegistration(redisServiceRegistry, new AutoServiceRegistrationProperties());
}
@Bean
@Primary
RedisDiscoveryClient redisDiscoveryClient() {
return new RedisDiscoveryClient();
}
}
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6、定义启动类
package com.hzgj.lyrk.member;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.discovery.composite.CompositeDiscoveryClientAutoConfiguration;
import org.springframework.cloud.client.discovery.simple.SimpleDiscoveryClientAutoConfiguration;
import org.springframework.context.ConfigurableApplicationContext;
@EnableDiscoveryClient
@SpringBootApplication(exclude = {SimpleDiscoveryClientAutoConfiguration.class, CompositeDiscoveryClientAutoConfiguration.class})
public class MemberApplication {
public static void main(String[] args) {
ConfigurableApplicationContext applicationContext = SpringApplication.run(MemberApplication.class, args);
DiscoveryClient discoveryClient = applicationContext.getBean(DiscoveryClient.class);
discoveryClient.getServices().forEach(action -> {
System.out.println(action);
});
}
}
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这里在SpringbootApplication注解里排除DiscoveryClient的默认装配。 当我们启动成功后可以发现，控制台已经输出对应的服务名称与地址：
我们再次通过gradle打包生成jar文件并运行: java -jar member-server-0.0.1-SNAPSHOT.jar --server.port=8800我们可以看到redis里已经缓存的有服务注册的值了：
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