注册中心代码使用 zookeeper 实现，我们通过图片来看看我们注册中心的架构。
首先说明， zookeeper 的实现思路和代码是参考架构探险这本书上的，另外在 github 和我前面配置文件中的 zookeeper 服务器是用的1个月免费适用的阿里云，大家也可以用它当测试用。
不多说，一次性给出注册中心全部代码。
客户端对应的注册中心接口
public interface RegisterCenter4Consumer {
/**
* 消费端初始化服务提供者信息本地缓存
*/
public void initProviderMap();
/**
* 消费端获取服务提供者信息
* @return
*/
public Map<String,List<ServiceProvider>> getServiceMetaDataMap4Consumer();
/**
* 消费端将消费者信息注册到 zookeeper 对应的节点下
* @param invokers
*/
public void registerConsumer(final List<ServiceConsumer> invokers);
}
服务端对应的注册中心接口
public interface RegisterCenter4Provider {
/**
* 服务端将服务提供者信息注册到 zookeeper 对应的节点下
* @param serivceList
*/
public void registerProvider(final List<ServiceProvider> serivceList);
/**
* 服务端获取服务提供者信息
* @return key：服务提供者接口 value：服务提供者服务方法列表
*/
public Map<String, List<ServiceProvider>> getProviderService();
}
注册中心实现类：
public class ZookeeperRegisterCenter implements RegisterCenter4Provider, RegisterCenter4Consumer {
private static ZookeeperRegisterCenter registerCenter = new ZookeeperRegisterCenter();
private ZookeeperRegisterCenter(){};
public static ZookeeperRegisterCenter getInstance(){
return registerCenter;
}
//服务提供者列表，key：服务提供者接口，value：服务提供者服务方法列表
private static final Map<String,List<ServiceProvider>> providerServiceMap = new ConcurrentHashMap<>();
//服务端 zookeeper 元信息，选择服务（第一次从zookeeper 拉取，后续由zookeeper监听机制主动更新）
private static final Map<String,List<ServiceProvider>> serviceData4Consumer = new ConcurrentHashMap<>();
//从配置文件中获取 zookeeper 服务地址列表
private static String ZK_SERIVCE = Configuration.getInstance().getAddress();
//从配置文件中获取 zookeeper 会话超时时间配置
private static int ZK_SESSION_TIME_OUT = 5000;
//从配置文件中获取 zookeeper 连接超时事件配置
private static int ZK_CONNECTION_TIME_OUT = 5000;
private static String ROOT_PATH = "/rpc_register";
public static String PROVIDER_TYPE = "/provider";
public static String CONSUMER_TYPE = "/consumer";
private static volatile ZkClient zkClient = null;
@Override
public void initProviderMap() {
if(serviceData4Consumer.isEmpty()){
serviceData4Consumer.putAll(fetchOrUpdateServiceMetaData());
}
}
@Override
public Map<String, List<ServiceProvider>> getServiceMetaDataMap4Consumer() {
return serviceData4Consumer;
}
@Override
public void registerConsumer(List<ServiceConsumer> consumers) {
if(consumers == null || consumers.size() == 0){
return;
}
//连接 zookeeper ，注册服务
synchronized (ZookeeperRegisterCenter.class){
if(zkClient == null){
zkClient = new ZkClient(ZK_SERIVCE,ZK_SESSION_TIME_OUT,ZK_CONNECTION_TIME_OUT, new SerializableSerializer());
}
//创建 zookeeper 命名空间
boolean exist = zkClient.exists(ROOT_PATH);
if(!exist){
zkClient.createPersistent(ROOT_PATH,true);
}
//创建服务提供者节点
exist = zkClient.exists((ROOT_PATH));
if(!exist){
zkClient.createPersistent(ROOT_PATH);
}
for(int i = 0; i< consumers.size();i++) {
ServiceConsumer consumer = consumers.get(i);
//创建服务消费者节点
String serviceNode = consumer.getConsumer().getName();
String servicePath = ROOT_PATH + CONSUMER_TYPE + "/" + serviceNode;
exist = zkClient.exists(servicePath);
System.out.println("exist:" + exist);
System.out.println("servicePath:" + servicePath);
if (!exist) {
zkClient.createPersistent(servicePath, true);
}
//创建当前服务器节点
InetAddress addr = null;
try {
addr = InetAddress.getLocalHost();
} catch (UnknownHostException e) {
e.printStackTrace();
}
String ip = addr.getHostAddress();
String currentServiceIpNode = servicePath + "/" + ip;
exist = zkClient.exists(currentServiceIpNode);
if (!exist) {
zkClient.createEphemeral(currentServiceIpNode);
}
}
}
}
@Override
public void registerProvider(List<ServiceProvider> serivceList) {
if(serivceList == null || serivceList.size() == 0){
return;
}
//连接 zookeeper，注册服务,加锁，将所有需要注册的服务放到providerServiceMap里面
synchronized (ZookeeperRegisterCenter.class){
for(ServiceProvider provider:serivceList){
//获取接口名称
String serviceItfKey = provider.getProvider().getName();
//先从当前服务提供者的集合里面获取
List<ServiceProvider> providers = providerServiceMap.get(serviceItfKey);
if(providers == null){
providers = new ArrayList<>();
}
providers.add(provider);
providerServiceMap.put(serviceItfKey,providers);
}
if(zkClient == null){
zkClient = new ZkClient(ZK_SERIVCE,ZK_SESSION_TIME_OUT,ZK_CONNECTION_TIME_OUT,new SerializableSerializer());
}
//创建当前应用 zookeeper 命名空间
boolean exist = zkClient.exists(ROOT_PATH);
if(!exist){
zkClient.createPersistent(ROOT_PATH,true);
}
//服务提供者节点
exist = zkClient.exists((ROOT_PATH));
if(!exist){
zkClient.createPersistent(ROOT_PATH);
}
for(Map.Entry<String,List<ServiceProvider>> entry:providerServiceMap.entrySet()){
//创建服务提供者节点
String serviceNode = entry.getKey();
String servicePath = ROOT_PATH +PROVIDER_TYPE +"/" + serviceNode;
exist = zkClient.exists(servicePath);
if(!exist){
zkClient.createPersistent(servicePath,true);
}
//创建当前服务器节点，这里是注册时使用，一个接口对应的ServiceProvider 只有一个
int serverPort = entry.getValue().get(0).getPort();
InetAddress addr = null;
try {
addr = InetAddress.getLocalHost();
} catch (UnknownHostException e) {
e.printStackTrace();
}
String ip = addr.getHostAddress();
String impl = (String)entry.getValue().get(0).getServiceObject();
String serviceIpNode = servicePath +"/" + ip + "|" + serverPort + "|" + impl;
System.out.println("serviceIpNode:" + serviceIpNode);
exist = zkClient.exists(serviceIpNode);
if(!exist){
//创建临时节点
zkClient.createEphemeral(serviceIpNode);
}
//监听注册服务的变化，同时更新数据到本地缓存
zkClient.subscribeChildChanges(servicePath, new IZkChildListener() {
@Override
public void handleChildChange(String s, List<String> list) throws Exception {
if(list == null){
list = new ArrayList<>();
}
//存活的服务 IP 列表
List<String> activeServiceIpList = new ArrayList<>();
for(String input:list){
String ip = StringUtils.split(input, "|").get(0);
activeServiceIpList.add(ip);
}
refreshActivityService(activeServiceIpList);
}
});
}
}
}
/**
*
* 在某个服务端获取自己暴露的服务
*/
@Override
public Map<String, List<ServiceProvider>> getProviderService() {
return providerServiceMap;
}
//利用ZK自动刷新当前存活的服务提供者列表数据
private void refreshActivityService(List<String> serviceIpList) {
if (serviceIpList == null||serviceIpList.isEmpty()) {
serviceIpList = new ArrayList<>();
}
Map<String, List<ServiceProvider>> currentServiceMetaDataMap = new HashMap<>();
for (Map.Entry<String, List<ServiceProvider>> entry : providerServiceMap.entrySet()) {
String key = entry.getKey();
List<ServiceProvider> providerServices = entry.getValue();
List<ServiceProvider> serviceMetaDataModelList = currentServiceMetaDataMap.get(key);
if (serviceMetaDataModelList == null) {
serviceMetaDataModelList = new ArrayList<>();
}
for (ServiceProvider serviceMetaData : providerServices) {
if (serviceIpList.contains(serviceMetaData.getIp())) {
serviceMetaDataModelList.add(serviceMetaData);
}
}
currentServiceMetaDataMap.put(key, serviceMetaDataModelList);
}
providerServiceMap.clear();
providerServiceMap.putAll(currentServiceMetaDataMap);
}
private void refreshServiceMetaDataMap(List<String> serviceIpList) {
if (serviceIpList == null) {
serviceIpList = new ArrayList<>();
}
Map<String, List<ServiceProvider>> currentServiceMetaDataMap = new HashMap<>();
for (Map.Entry<String, List<ServiceProvider>> entry : serviceData4Consumer.entrySet()) {
String serviceItfKey = entry.getKey();
List<ServiceProvider> serviceList = entry.getValue();
List<ServiceProvider> providerServiceList = currentServiceMetaDataMap.get(serviceItfKey);
if (providerServiceList == null) {
providerServiceList = new ArrayList<>();
}
for (ServiceProvider serviceMetaData : serviceList) {
if (serviceIpList.contains(serviceMetaData.getIp())) {
providerServiceList.add(serviceMetaData);
}
}
currentServiceMetaDataMap.put(serviceItfKey, providerServiceList);
}
serviceData4Consumer.clear();
serviceData4Consumer.putAll(currentServiceMetaDataMap);
}
private Map<String, List<ServiceProvider>> fetchOrUpdateServiceMetaData() {
final Map<String, List<ServiceProvider>> providerServiceMap = new ConcurrentHashMap<>();
//连接zk
synchronized (ZookeeperRegisterCenter.class) {
if (zkClient == null) {
zkClient = new ZkClient(ZK_SERIVCE, ZK_SESSION_TIME_OUT, ZK_CONNECTION_TIME_OUT, new SerializableSerializer());
}
}
//从ZK获取服务提供者列表
String providePath = ROOT_PATH+PROVIDER_TYPE;
System.out.println("111111:"+providePath);
List<String> providerServices = zkClient.getChildren(providePath);
System.out.println(providerServices.toString());
for (String serviceName : providerServices) {
String servicePath = providePath +"/"+ serviceName;
System.out.println("1100:"+servicePath);
List<String> ipPathList = zkClient.getChildren(servicePath);
System.out.println("ipPathList:"+ipPathList.toString());
for (String ipPath : ipPathList) {
String serverIp = ipPath.split("\|")[0];
String serverPort = ipPath.split("\|")[1];
String impl = ipPath.split("\|")[2];
List<ServiceProvider> providerServiceList = providerServiceMap.get(serviceName);
if (providerServiceList == null) {
providerServiceList = new ArrayList<>();
}
ServiceProvider providerService = new ServiceProvider();
try {
Class clazz = Class.forName(serviceName);
providerService.setProvider(clazz);
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
providerService.setIp(serverIp);
providerService.setPort(Integer.parseInt(serverPort));
providerService.setServiceObject(impl);
providerService.setGroupName("");
providerServiceList.add(providerService);
providerServiceMap.put(serviceName, providerServiceList);
}
//监听注册服务的变化,同时更新数据到本地缓存
zkClient.subscribeChildChanges(servicePath, new IZkChildListener() {
@Override
public void handleChildChange(String parentPath, List<String> currentChilds) throws Exception {
if (currentChilds == null) {
currentChilds = new ArrayList<>();
}
List<String> activeServiceIpList = new ArrayList<>();
for(String input:currentChilds){
String ip = StringUtils.split(input, "|").get(0);
activeServiceIpList.add(ip);
}
refreshServiceMetaDataMap(activeServiceIpList);
}
});
}
return providerServiceMap;
}
}
写完这部分整个 rpc 框架也就实现了，测试的客户端和服务端在代码里也有，这里就不贴出来了。平时时间有限，只能下班和周末的时间来写，整个框架肯定有不足和错误的地方，也有可以改进的地方。希望大家能够不吝指教，互相进步。
我只是想将自己思考的过程给大家展示出来，希望大家一起讨论这些问题，看看还有哪些能够改进的地方。
需要改进的地方：
- 服务端的启动方式。
- 更高并发的改进。
- 服务治理。
- 监测中心。
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最后给出源码 github 地址，源码 编码和码字不易，如果您觉得学到了东西就请在 github 上加个 star， 当然在 github 上提出问题一起改进是最好的。