RegistryProtocol實現了Protocol介面，當作為服務提供者時實現服務註冊到註冊中心，當作為服務消費者時實現從註冊中心載入服務提供者URL,並通過提供者URL建立對應的協議實現類。
入參 url 資料如下 registry://zk.com:2181/com.alibaba.dubbo.registry.RegistryService?application=user&dubbo=2.8.4&organization=meitun&owner=wh-dengqiao&pid=13204&refer=遠端服務資訊（包括服務名稱，分組，重試，超時等資訊）®ister=true®istry=zookeeper×tamp=1542266415442
public class RegistryProtocol implements Protocol {
private Cluster cluster;
public void setCluster(Cluster cluster) {
this.cluster = cluster;
}
private Protocol protocol;
public void setProtocol(Protocol protocol) {
this.protocol = protocol;
}
private RegistryFactory registryFactory;
public void setRegistryFactory(RegistryFactory registryFactory) {
this.registryFactory = registryFactory;
}
private ProxyFactory proxyFactory;
public void setProxyFactory(ProxyFactory proxyFactory) {
this.proxyFactory = proxyFactory;
}
public <T> Invoker<T> refer(Class<T> type, URL url) throws RpcException {
//url被替換成zookeeper://zk.com:2181/com.alibaba.dubbo.registry.RegistryService
url = url.setProtocol(url.getParameter(Constants.REGISTRY_KEY, Constants.DEFAULT_REGISTRY)).removeParameter(Constants.REGISTRY_KEY);
//registryFactory為SPI介面，會根據url中protocol的值呼叫真實註冊工廠實現類獲取註冊服務，相當於呼叫Registry registry = zookeeperRegistryFactory.getRegistry(url);
Registry registry = registryFactory.getRegistry(url);
if (RegistryService.class.equals(type)) {
return proxyFactory.getInvoker((T) registry, type, url);
}
// group="a,b" or group="*"
Map<String, String> qs = StringUtils.parseQueryString(url.getParameterAndDecoded(Constants.REFER_KEY));
String group = qs.get(Constants.GROUP_KEY);
if (group != null && group.length() > 0 ) {
if ( ( Constants.COMMA_SPLIT_PATTERN.split( group ) ).length > 1
|| "*".equals( group ) ) {
return doRefer( getMergeableCluster(), registry, type, url );
}
}
return doRefer(cluster, registry, type, url);
}
private <T> Invoker<T> doRefer(Cluster cluster, Registry registry, Class<T> type, URL url) {
//RegistryDirectory作為服務提供者容器，儲存了服務提供者列表，並且實現了服務提供者根據註冊中心通知動態更新
RegistryDirectory<T> directory = new RegistryDirectory<T>(type, url);
directory.setRegistry(registry);
directory.setProtocol(protocol);
URL subscribeUrl = new URL(Constants.CONSUMER_PROTOCOL, NetUtils.getLocalHost(), 0, type.getName(), directory.getUrl().getParameters());
if (! Constants.ANY_VALUE.equals(url.getServiceInterface())
&& url.getParameter(Constants.REGISTER_KEY, true)) {
registry.register(subscribeUrl.addParameters(Constants.CATEGORY_KEY, Constants.CONSUMERS_CATEGORY,
Constants.CHECK_KEY, String.valueOf(false)));
}
//訂閱註冊中心資料變更
directory.subscribe(subscribeUrl.addParameter(Constants.CATEGORY_KEY,
Constants.PROVIDERS_CATEGORY
+ "," + Constants.CONFIGURATORS_CATEGORY
+ "," + Constants.ROUTERS_CATEGORY));
//cluster實現了將多個服務提供者轉換為單個服務提供者，使用的策略有failover失敗重試 failfast立即失敗 等等
return cluster.join(directory);
}
}
複製程式碼通過以上可以看到服務註冊和服務引用最核心的實現類RegistryDirectory，Registry實現類。 ZookeeperRegistry註冊中心目錄示意圖
public interface RegistryService {
/**
* 註冊資料，比如：提供者地址，消費者地址，路由規則，覆蓋規則，等資料。
*
* 註冊需處理契約：<br>
* 1. 當URL設定了check=false時，註冊失敗後不報錯，在後臺定時重試，否則丟擲異常。<br>
* 2. 當URL設定了dynamic=false引數，則需持久儲存，否則，當註冊者出現斷電等情況異常退出時，需自動刪除。<br>
* 3. 當URL設定了category=routers時，表示分類儲存，預設類別為providers，可按分類部分通知資料。<br>
* 4. 當註冊中心重啟，網路抖動，不能丟失資料，包括斷線自動刪除資料。<br>
* 5. 允許URI相同但引數不同的URL並存，不能覆蓋。<br>
*
* @param url 註冊資訊，不允許為空，如：dubbo://10.20.153.10/com.alibaba.foo.BarService?version=1.0.0&application=kylin
*/
void register(URL url);
/**
* 取消註冊.
*
* 取消註冊需處理契約：<br>
* 1. 如果是dynamic=false的持久儲存資料，找不到註冊資料，則拋IllegalStateException，否則忽略。<br>
* 2. 按全URL匹配取消註冊。<br>
*
* @param url 註冊資訊，不允許為空，如：dubbo://10.20.153.10/com.alibaba.foo.BarService?version=1.0.0&application=kylin
*/
void unregister(URL url);
/**
* 訂閱符合條件的已註冊資料，當有註冊資料變更時自動推送.
*
* 訂閱需處理契約：<br>
* 1. 當URL設定了check=false時，訂閱失敗後不報錯，在後臺定時重試。<br>
* 2. 當URL設定了category=routers，只通知指定分類的資料，多個分類用逗號分隔，並允許星號通配，表示訂閱所有分類資料。<br>
* 3. 允許以interface,group,version,classifier作為條件查詢，如：interface=com.alibaba.foo.BarService&version=1.0.0<br>
* 4. 並且查詢條件允許星號通配，訂閱所有介面的所有分組的所有版本，或：interface=*&group=*&version=*&classifier=*<br>
* 5. 當註冊中心重啟，網路抖動，需自動恢復訂閱請求。<br>
* 6. 允許URI相同但引數不同的URL並存，不能覆蓋。<br>
* 7. 必須阻塞訂閱過程，等第一次通知完後再返回。<br>
*
* @param url 訂閱條件，不允許為空，如：consumer://10.20.153.10/com.alibaba.foo.BarService?version=1.0.0&application=kylin
* @param listener 變更事件監聽器，不允許為空
*/
void subscribe(URL url, NotifyListener listener);
/**
* 取消訂閱.
*
* 取消訂閱需處理契約：<br>
* 1. 如果沒有訂閱，直接忽略。<br>
* 2. 按全URL匹配取消訂閱。<br>
*
* @param url 訂閱條件，不允許為空，如：consumer://10.20.153.10/com.alibaba.foo.BarService?version=1.0.0&application=kylin
* @param listener 變更事件監聽器，不允許為空
*/
void unsubscribe(URL url, NotifyListener listener);
/**
* 查詢符合條件的已註冊資料，與訂閱的推模式相對應，這裡為拉模式，只返回一次結果。
*
* @see com.alibaba.dubbo.registry.NotifyListener#notify(List)
* @param url 查詢條件，不允許為空，如：consumer://10.20.153.10/com.alibaba.foo.BarService?version=1.0.0&application=kylin
* @return 已註冊資訊列表，可能為空，含義同{@link com.alibaba.dubbo.registry.NotifyListener#notify(List<URL>)}的引數。
*/
List<URL> lookup(URL url);
}
public interface Registry extends Node, RegistryService {
}
複製程式碼註冊服務的類層次結構為Registry > AbstractRegistry > FailbackRegistry >ZookeeperRegistry
public abstract class AbstractRegistry implements Registry{
//記錄所有註冊的url
private final Set<URL> registered = new ConcurrentHashSet<URL>();
//記錄所有訂閱的url和通知監聽器
private final ConcurrentMap<URL, Set<NotifyListener>> subscribed = new ConcurrentHashMap<URL, Set<NotifyListener>>();
//記錄所有已經通知的url和服務提供者列表
private final ConcurrentMap<URL, Map<String, List<URL>>> notified = new ConcurrentHashMap<URL, Map<String, List<URL>>>();
public void register(URL url) {
if (url == null) {
throw new IllegalArgumentException("register url == null");
}
if (logger.isInfoEnabled()){
logger.info("Register: " + url);
}
registered.add(url);
}
public void subscribe(URL url, NotifyListener listener) {
if (url == null) {
throw new IllegalArgumentException("subscribe url == null");
}
if (listener == null) {
throw new IllegalArgumentException("subscribe listener == null");
}
if (logger.isInfoEnabled()){
logger.info("Subscribe: " + url);
}
Set<NotifyListener> listeners = subscribed.get(url);
if (listeners == null) {
subscribed.putIfAbsent(url, new ConcurrentHashSet<NotifyListener>());
listeners = subscribed.get(url);
}
listeners.add(listener);
}
}
public abstract class FailbackRegistry extends AbstractRegistry{
// 定時任務執行器
private final ScheduledExecutorService retryExecutor = Executors.newScheduledThreadPool(1, new NamedThreadFactory("DubboRegistryFailedRetryTimer", true));
// 記錄所有註冊失敗的URL列表
private final Set<URL> failedUnregistered = new ConcurrentHashSet<URL>();
// 記錄所有訂閱失敗的URL
private final ConcurrentMap<URL, Set<NotifyListener>> failedSubscribed = new ConcurrentHashMap<URL, Set<NotifyListener>>();
// 記錄所有取消訂閱失敗的URL
private final ConcurrentMap<URL, Set<NotifyListener>> failedUnsubscribed = new ConcurrentHashMap<URL, Set<NotifyListener>>();
// 記錄所有取消通知失敗的URL
private final ConcurrentMap<URL, Map<NotifyListener, List<URL>>> failedNotified = new ConcurrentHashMap<URL, Map<NotifyListener, List<URL>>>();
public FailbackRegistry(URL url) {
super(url);
int retryPeriod = url.getParameter(Constants.REGISTRY_RETRY_PERIOD_KEY, Constants.DEFAULT_REGISTRY_RETRY_PERIOD);
this.retryFuture = retryExecutor.scheduleWithFixedDelay(new Runnable() {
public void run() {
// 檢測並連線註冊中心
try {
retry();
} catch (Throwable t) { // 防禦性容錯
logger.error("Unexpected error occur at failed retry, cause: " + t.getMessage(), t);
}
}
}, retryPeriod, retryPeriod, TimeUnit.MILLISECONDS);
}
@Override
public void register(URL url) {
super.register(url);
failedRegistered.remove(url);
failedUnregistered.remove(url);
try {
// 向伺服器端傳送註冊請求
doRegister(url);
} catch (Exception e) {
Throwable t = e;
// 如果開啟了啟動時檢測，則直接丟擲異常
boolean check = getUrl().getParameter(Constants.CHECK_KEY, true)
&& url.getParameter(Constants.CHECK_KEY, true)
&& ! Constants.CONSUMER_PROTOCOL.equals(url.getProtocol());
boolean skipFailback = t instanceof SkipFailbackWrapperException;
if (check || skipFailback) {
if(skipFailback) {
t = t.getCause();
}
throw new IllegalStateException("Failed to register " + url + " to registry " + getUrl().getAddress() + ", cause: " + t.getMessage(), t);
} else {
logger.error("Failed to register " + url + ", waiting for retry, cause: " + t.getMessage(), t);
}
// 將失敗的註冊請求記錄到失敗列表，定時重試
failedRegistered.add(url);
}
}
public void subscribe(URL url, NotifyListener listener) {
super.subscribe(url, listener);
removeFailedSubscribed(url, listener);
try {
// 向伺服器端傳送訂閱請求
doSubscribe(url, listener);
} catch (Exception e) {
Throwable t = e;
List<URL> urls = getCacheUrls(url);
if (urls != null && urls.size() > 0) {
notify(url, listener, urls);
logger.error("Failed to subscribe " + url + ", Using cached list: " + urls + " from cache file: " + getUrl().getParameter(Constants.FILE_KEY, System.getProperty("user.home") + "/dubbo-registry-" + url.getHost() + ".cache") + ", cause: " + t.getMessage(), t);
} else {
// 如果開啟了啟動時檢測，則直接丟擲異常
boolean check = getUrl().getParameter(Constants.CHECK_KEY, true)
&& url.getParameter(Constants.CHECK_KEY, true);
boolean skipFailback = t instanceof SkipFailbackWrapperException;
if (check || skipFailback) {
if(skipFailback) {
t = t.getCause();
}
throw new IllegalStateException("Failed to subscribe " + url + ", cause: " + t.getMessage(), t);
} else {
logger.error("Failed to subscribe " + url + ", waiting for retry, cause: " + t.getMessage(), t);
}
}
// 將失敗的訂閱請求記錄到失敗列表，定時重試
addFailedSubscribed(url, listener);
}
}
//失去和註冊中心連線後重新註冊和訂閱
protected void recover() throws Exception {
// register
Set<URL> recoverRegistered = new HashSet<URL>(getRegistered());
if (! recoverRegistered.isEmpty()) {
if (logger.isInfoEnabled()) {
logger.info("Recover register url " + recoverRegistered);
}
for (URL url : recoverRegistered) {
failedRegistered.add(url);
}
}
// subscribe
Map<URL, Set<NotifyListener>> recoverSubscribed = new HashMap<URL, Set<NotifyListener>>(getSubscribed());
if (! recoverSubscribed.isEmpty()) {
if (logger.isInfoEnabled()) {
logger.info("Recover subscribe url " + recoverSubscribed.keySet());
}
for (Map.Entry<URL, Set<NotifyListener>> entry : recoverSubscribed.entrySet()) {
URL url = entry.getKey();
for (NotifyListener listener : entry.getValue()) {
addFailedSubscribed(url, listener);
}
}
}
}
// 重試失敗的動作
protected void retry() {
if (! failedRegistered.isEmpty()) {
Set<URL> failed = new HashSet<URL>(failedRegistered);
if (failed.size() > 0) {
if (logger.isInfoEnabled()) {
logger.info("Retry register " + failed);
}
try {
for (URL url : failed) {
try {
doRegister(url);
failedRegistered.remove(url);
} catch (Throwable t) { // 忽略所有異常，等待下次重試
logger.warn("Failed to retry register " + failed + ", waiting for again, cause: " + t.getMessage(), t);
}
}
} catch (Throwable t) { // 忽略所有異常，等待下次重試
logger.warn("Failed to retry register " + failed + ", waiting for again, cause: " + t.getMessage(), t);
}
}
}
if(! failedUnregistered.isEmpty()) {
Set<URL> failed = new HashSet<URL>(failedUnregistered);
if (failed.size() > 0) {
if (logger.isInfoEnabled()) {
logger.info("Retry unregister " + failed);
}
try {
for (URL url : failed) {
try {
doUnregister(url);
failedUnregistered.remove(url);
} catch (Throwable t) { // 忽略所有異常，等待下次重試
logger.warn("Failed to retry unregister " + failed + ", waiting for again, cause: " + t.getMessage(), t);
}
}
} catch (Throwable t) { // 忽略所有異常，等待下次重試
logger.warn("Failed to retry unregister " + failed + ", waiting for again, cause: " + t.getMessage(), t);
}
}
}
if (! failedSubscribed.isEmpty()) {
Map<URL, Set<NotifyListener>> failed = new HashMap<URL, Set<NotifyListener>>(failedSubscribed);
for (Map.Entry<URL, Set<NotifyListener>> entry : new HashMap<URL, Set<NotifyListener>>(failed).entrySet()) {
if (entry.getValue() == null || entry.getValue().size() == 0) {
failed.remove(entry.getKey());
}
}
if (failed.size() > 0) {
if (logger.isInfoEnabled()) {
logger.info("Retry subscribe " + failed);
}
try {
for (Map.Entry<URL, Set<NotifyListener>> entry : failed.entrySet()) {
URL url = entry.getKey();
Set<NotifyListener> listeners = entry.getValue();
for (NotifyListener listener : listeners) {
try {
doSubscribe(url, listener);
listeners.remove(listener);
} catch (Throwable t) { // 忽略所有異常，等待下次重試
logger.warn("Failed to retry subscribe " + failed + ", waiting for again, cause: " + t.getMessage(), t);
}
}
}
} catch (Throwable t) { // 忽略所有異常，等待下次重試
logger.warn("Failed to retry subscribe " + failed + ", waiting for again, cause: " + t.getMessage(), t);
}
}
}
if (! failedUnsubscribed.isEmpty()) {
Map<URL, Set<NotifyListener>> failed = new HashMap<URL, Set<NotifyListener>>(failedUnsubscribed);
for (Map.Entry<URL, Set<NotifyListener>> entry : new HashMap<URL, Set<NotifyListener>>(failed).entrySet()) {
if (entry.getValue() == null || entry.getValue().size() == 0) {
failed.remove(entry.getKey());
}
}
if (failed.size() > 0) {
if (logger.isInfoEnabled()) {
logger.info("Retry unsubscribe " + failed);
}
try {
for (Map.Entry<URL, Set<NotifyListener>> entry : failed.entrySet()) {
URL url = entry.getKey();
Set<NotifyListener> listeners = entry.getValue();
for (NotifyListener listener : listeners) {
try {
doUnsubscribe(url, listener);
listeners.remove(listener);
} catch (Throwable t) { // 忽略所有異常，等待下次重試
logger.warn("Failed to retry unsubscribe " + failed + ", waiting for again, cause: " + t.getMessage(), t);
}
}
}
} catch (Throwable t) { // 忽略所有異常，等待下次重試
logger.warn("Failed to retry unsubscribe " + failed + ", waiting for again, cause: " + t.getMessage(), t);
}
}
}
if (! failedNotified.isEmpty()) {
Map<URL, Map<NotifyListener, List<URL>>> failed = new HashMap<URL, Map<NotifyListener, List<URL>>>(failedNotified);
for (Map.Entry<URL, Map<NotifyListener, List<URL>>> entry : new HashMap<URL, Map<NotifyListener, List<URL>>>(failed).entrySet()) {
if (entry.getValue() == null || entry.getValue().size() == 0) {
failed.remove(entry.getKey());
}
}
if (failed.size() > 0) {
if (logger.isInfoEnabled()) {
logger.info("Retry notify " + failed);
}
try {
for (Map<NotifyListener, List<URL>> values : failed.values()) {
for (Map.Entry<NotifyListener, List<URL>> entry : values.entrySet()) {
try {
NotifyListener listener = entry.getKey();
List<URL> urls = entry.getValue();
listener.notify(urls);
values.remove(listener);
} catch (Throwable t) { // 忽略所有異常，等待下次重試
logger.warn("Failed to retry notify " + failed + ", waiting for again, cause: " + t.getMessage(), t);
}
}
}
} catch (Throwable t) { // 忽略所有異常，等待下次重試
logger.warn("Failed to retry notify " + failed + ", waiting for again, cause: " + t.getMessage(), t);
}
}
}
}
}
public class ZookeeperRegistry extends FailbackRegistry {
private final ConcurrentMap<URL, ConcurrentMap<NotifyListener, ChildListener>> zkListeners = new ConcurrentHashMap<URL, ConcurrentMap<NotifyListener, ChildListener>>();
private final ZookeeperClient zkClient;
public ZookeeperRegistry(URL url, ZookeeperTransporter zookeeperTransporter) {
super(url);
if (url.isAnyHost()) {
throw new IllegalStateException("registry address == null");
}
String group = url.getParameter(Constants.GROUP_KEY, DEFAULT_ROOT);
if (! group.startsWith(Constants.PATH_SEPARATOR)) {
group = Constants.PATH_SEPARATOR + group;
}
this.root = group;
zkClient = zookeeperTransporter.connect(url);
zkClient.addStateListener(new StateListener() {
public void stateChanged(int state) {
if (state == RECONNECTED) {
try {
recover();
} catch (Exception e) {
logger.error(e.getMessage(), e);
}
}
}
});
}
protected void doRegister(URL url) {
try {
zkClient.create(toUrlPath(url), url.getParameter(Constants.DYNAMIC_KEY, true));
} catch (Throwable e) {
throw new RpcException("Failed to register " + url + " to zookeeper " + getUrl() + ", cause: " + e.getMessage(), e);
}
}
protected void doSubscribe(final URL url, final NotifyListener listener) {
try {
if (Constants.ANY_VALUE.equals(url.getServiceInterface())) {
String root = toRootPath();
ConcurrentMap<NotifyListener, ChildListener> listeners = zkListeners.get(url);
if (listeners == null) {
zkListeners.putIfAbsent(url, new ConcurrentHashMap<NotifyListener, ChildListener>());
listeners = zkListeners.get(url);
}
ChildListener zkListener = listeners.get(listener);
if (zkListener == null) {
listeners.putIfAbsent(listener, new ChildListener() {
public void childChanged(String parentPath, List<String> currentChilds) {
for (String child : currentChilds) {
child = URL.decode(child);
if (! anyServices.contains(child)) {
anyServices.add(child);
subscribe(url.setPath(child).addParameters(Constants.INTERFACE_KEY, child,
Constants.CHECK_KEY, String.valueOf(false)), listener);
}
}
}
});
zkListener = listeners.get(listener);
}
zkClient.create(root, false);
List<String> services = zkClient.addChildListener(root, zkListener);
if (services != null && services.size() > 0) {
for (String service : services) {
service = URL.decode(service);
anyServices.add(service);
subscribe(url.setPath(service).addParameters(Constants.INTERFACE_KEY, service,
Constants.CHECK_KEY, String.valueOf(false)), listener);
}
}
} else {
List<URL> urls = new ArrayList<URL>();
for (String path : toCategoriesPath(url)) {
ConcurrentMap<NotifyListener, ChildListener> listeners = zkListeners.get(url);
if (listeners == null) {
zkListeners.putIfAbsent(url, new ConcurrentHashMap<NotifyListener, ChildListener>());
listeners = zkListeners.get(url);
}
ChildListener zkListener = listeners.get(listener);
if (zkListener == null) {
listeners.putIfAbsent(listener, new ChildListener() {
public void childChanged(String parentPath, List<String> currentChilds) {
ZookeeperRegistry.this.notify(url, listener, toUrlsWithEmpty(url, parentPath, currentChilds));
}
});
zkListener = listeners.get(listener);
}
zkClient.create(path, false);
List<String> children = zkClient.addChildListener(path, zkListener);
if (children != null) {
urls.addAll(toUrlsWithEmpty(url, path, children));
}
}
//該方法會呼叫listener.notify(urls)方法，也就是RegistryDirectory的notify(urls)方法
notify(url, listener, urls);
}
} catch (Throwable e) {
throw new RpcException("Failed to subscribe " + url + " to zookeeper " + getUrl() + ", cause: " + e.getMessage(), e);
}
}
}
public class RegistryDirectory<T> extends AbstractDirectory<T> implements NotifyListener {
// Map<url, Invoker> cache service url to invoker mapping.
private volatile Map<String, Invoker<T>> urlInvokerMap; // 初始為null以及中途可能被賦為null，請使用區域性變數引用
// Map<methodName, Invoker> cache service method to invokers mapping.
private volatile Map<String, List<Invoker<T>>> methodInvokerMap; // 初始為null以及中途可能被賦為null，請使用區域性變數引用
public void subscribe(URL url) {
setConsumerUrl(url);
//注意這個地方RegistryDirectory實現了NotifyListener介面
registry.subscribe(url, this);
}
public synchronized void notify(List<URL> urls) {
List<URL> invokerUrls = new ArrayList<URL>();
List<URL> routerUrls = new ArrayList<URL>();
List<URL> configuratorUrls = new ArrayList<URL>();
for (URL url : urls) {
String protocol = url.getProtocol();
String category = url.getParameter(Constants.CATEGORY_KEY, Constants.DEFAULT_CATEGORY);
if (Constants.ROUTERS_CATEGORY.equals(category)
|| Constants.ROUTE_PROTOCOL.equals(protocol)) {
routerUrls.add(url);
} else if (Constants.CONFIGURATORS_CATEGORY.equals(category)
|| Constants.OVERRIDE_PROTOCOL.equals(protocol)) {
configuratorUrls.add(url);
} else if (Constants.PROVIDERS_CATEGORY.equals(category)) {
invokerUrls.add(url);
} else {
logger.warn("Unsupported category " + category + " in notified url: " + url + " from registry " + getUrl().getAddress() + " to consumer " + NetUtils.getLocalHost());
}
}
// configurators
if (configuratorUrls != null && configuratorUrls.size() >0 ){
this.configurators = toConfigurators(configuratorUrls);
}
// routers
if (routerUrls != null && routerUrls.size() >0 ){
List<Router> routers = toRouters(routerUrls);
if(routers != null){ // null - do nothing
setRouters(routers);
}
}
List<Configurator> localConfigurators = this.configurators; // local reference
// 合併override引數
this.overrideDirectoryUrl = directoryUrl;
if (localConfigurators != null && localConfigurators.size() > 0) {
for (Configurator configurator : localConfigurators) {
this.overrideDirectoryUrl = configurator.configure(overrideDirectoryUrl);
}
}
// providers
refreshInvoker(invokerUrls);
}
/**
* 根據invokerURL列表轉換為invoker列表。轉換規則如下：
* 1.如果url已經被轉換為invoker，則不在重新引用，直接從快取中獲取，注意如果url中任何一個引數變更也會重新引用
* 2.如果傳入的invoker列表不為空，則表示最新的invoker列表
* 3.如果傳入的invokerUrl列表是空，則表示只是下發的override規則或route規則，需要重新交叉對比，決定是否需要重新引用。
* @param invokerUrls 傳入的引數不能為null
*/
private void refreshInvoker(List<URL> invokerUrls){
if (invokerUrls != null && invokerUrls.size() == 1 && invokerUrls.get(0) != null
&& Constants.EMPTY_PROTOCOL.equals(invokerUrls.get(0).getProtocol())) {
this.forbidden = true; // 禁止訪問
this.methodInvokerMap = null; // 置空列表
destroyAllInvokers(); // 關閉所有Invoker
} else {
this.forbidden = false; // 允許訪問
Map<String, Invoker<T>> oldUrlInvokerMap = this.urlInvokerMap; // local reference
if (invokerUrls.size() == 0 && this.cachedInvokerUrls != null){
invokerUrls.addAll(this.cachedInvokerUrls);
} else {
this.cachedInvokerUrls = new HashSet<URL>();
this.cachedInvokerUrls.addAll(invokerUrls);//快取invokerUrls列表，便於交叉對比
}
if (invokerUrls.size() ==0 ){
return;
}
Map<String, Invoker<T>> newUrlInvokerMap = toInvokers(invokerUrls) ;// 將URL列表轉成Invoker列表
Map<String, List<Invoker<T>>> newMethodInvokerMap = toMethodInvokers(newUrlInvokerMap); // 換方法名對映Invoker列表
// state change
//如果計算錯誤，則不進行處理.
if (newUrlInvokerMap == null || newUrlInvokerMap.size() == 0 ){
logger.error(new IllegalStateException("urls to invokers error .invokerUrls.size :"+invokerUrls.size() + ", invoker.size :0. urls :"+invokerUrls.toString()));
return ;
}
this.methodInvokerMap = multiGroup ? toMergeMethodInvokerMap(newMethodInvokerMap) : newMethodInvokerMap;
this.urlInvokerMap = newUrlInvokerMap;
try{
destroyUnusedInvokers(oldUrlInvokerMap,newUrlInvokerMap); // 關閉未使用的Invoker
}catch (Exception e) {
logger.warn("destroyUnusedInvokers error. ", e);
}
}
}
}
/**
* 將urls轉成invokers,如果url已經被refer過，不再重新引用。
*
* @param urls
* @param overrides
* @param query
* @return invokers
*/
private Map<String, Invoker<T>> toInvokers(List<URL> urls) {
Map<String, Invoker<T>> newUrlInvokerMap = new HashMap<String, Invoker<T>>();
if(urls == null || urls.size() == 0){
return newUrlInvokerMap;
}
Set<String> keys = new HashSet<String>();
String queryProtocols = this.queryMap.get(Constants.PROTOCOL_KEY);
for (URL providerUrl : urls) {
//如果reference端配置了protocol，則只選擇匹配的protocol
if (queryProtocols != null && queryProtocols.length() >0) {
boolean accept = false;
String[] acceptProtocols = queryProtocols.split(",");
for (String acceptProtocol : acceptProtocols) {
if (providerUrl.getProtocol().equals(acceptProtocol)) {
accept = true;
break;
}
}
if (!accept) {
continue;
}
}
if (Constants.EMPTY_PROTOCOL.equals(providerUrl.getProtocol())) {
continue;
}
if (! ExtensionLoader.getExtensionLoader(Protocol.class).hasExtension(providerUrl.getProtocol())) {
logger.error(new IllegalStateException("Unsupported protocol " + providerUrl.getProtocol() + " in notified url: " + providerUrl + " from registry " + getUrl().getAddress() + " to consumer " + NetUtils.getLocalHost()
+ ", supported protocol: "+ExtensionLoader.getExtensionLoader(Protocol.class).getSupportedExtensions()));
continue;
}
URL url = mergeUrl(providerUrl);
String key = url.toFullString(); // URL引數是排序的
if (keys.contains(key)) { // 重複URL
continue;
}
keys.add(key);
// 快取key為沒有合併消費端引數的URL，不管消費端如何合併引數，如果服務端URL發生變化，則重新refer
Map<String, Invoker<T>> localUrlInvokerMap = this.urlInvokerMap; // local reference
Invoker<T> invoker = localUrlInvokerMap == null ? null : localUrlInvokerMap.get(key);
if (invoker == null) { // 快取中沒有，重新refer
try {
boolean enabled = true;
if (url.hasParameter(Constants.DISABLED_KEY)) {
enabled = ! url.getParameter(Constants.DISABLED_KEY, false);
} else {
enabled = url.getParameter(Constants.ENABLED_KEY, true);
}
if (enabled) {
invoker = new InvokerDelegete<T>(protocol.refer(serviceType, url), url, providerUrl);
}
} catch (Throwable t) {
logger.error("Failed to refer invoker for interface:"+serviceType+",url:("+url+")" + t.getMessage(), t);
}
if (invoker != null) { // 將新的引用放入快取
newUrlInvokerMap.put(key, invoker);
}
}else {
newUrlInvokerMap.put(key, invoker);
}
}
keys.clear();
return newUrlInvokerMap;
}
//通過遠端呼叫入參查詢匹配的Invoker列表
public List<Invoker<T>> doList(Invocation invocation) {
if (forbidden) {
throw new RpcException(RpcException.FORBIDDEN_EXCEPTION, "Forbid consumer " + NetUtils.getLocalHost() + " access service " + getInterface().getName() + " from registry " + getUrl().getAddress() + " use dubbo version " + Version.getVersion() + ", Please check registry access list (whitelist/blacklist).");
}
List<Invoker<T>> invokers = null;
Map<String, List<Invoker<T>>> localMethodInvokerMap = this.methodInvokerMap; // local reference
if (localMethodInvokerMap != null && localMethodInvokerMap.size() > 0) {
String methodName = RpcUtils.getMethodName(invocation);
Object[] args = RpcUtils.getArguments(invocation);
if(args != null && args.length > 0 && args[0] != null
&& (args[0] instanceof String || args[0].getClass().isEnum())) {
invokers = localMethodInvokerMap.get(methodName + "." + args[0]); // 可根據第一個引數列舉路由
}
if(invokers == null) {
invokers = localMethodInvokerMap.get(methodName);
}
if(invokers == null) {
invokers = localMethodInvokerMap.get(Constants.ANY_VALUE);
}
if(invokers == null) {
Iterator<List<Invoker<T>>> iterator = localMethodInvokerMap.values().iterator();
if (iterator.hasNext()) {
invokers = iterator.next();
}
}
}
return invokers == null ? new ArrayList<Invoker<T>>(0) : invokers;
}
複製程式碼RegistryDirectory實現的功能如下： 呼叫Registry註冊服務訂閱服務提供者列表，RegistryDirectory實現了NotifyListener通知回撥介面，當註冊中心服務提供者有變更時回撥RegistryDirectory的notify方法。 然後根據通知回撥返回的url 呼叫protocol.refer(serviceType, url) 建立真正的Invoker, protocol為自適應實現類，根據url引數中的protocol呼叫真正的protocol實現類，如果是dubbo協議提供者 會呼叫DubboProtocol建立Invoker,接下來要介紹DubboProtocol類。