@(dubbo源碼分析)[#rpc]
dubbo源碼分析（三）：dubbo服務(wù)暴露-本地服務(wù)暴露分析
暴露過程分為兩步
- 將本地接口實(shí)現(xiàn)類轉(zhuǎn)化為invoker
- 將invoker轉(zhuǎn)化為ExPorter
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private void exportLocal(URL url) {
if (!Constants.LOCAL_PROTOCOL.equalsIgnoreCase(url.getProtocol())) {
URL local = URL.valueOf(url.toFullString())
.setProtocol(Constants.LOCAL_PROTOCOL)
.setHost(NetUtils.LOCALHOST)
.setPort(0);
Exporter<?> exporter = protocol.export(
proxyFactory.getInvoker(ref, (Class) interfaceClass, local));
exporters.add(exporter);
logger.info("Export dubbo service " + interfaceClass.getName() + " to local registry");
}
}
一澄步、本地方法轉(zhuǎn)為invoker
proxyFactory.getInvoker(ref, (Class) interfaceClass, local)
這部分代碼是如何將本地接口實(shí)現(xiàn)類轉(zhuǎn)化為Invoker的
通過debug的方式，進(jìn)入了JavassistProxyFactory中
ProxyFactory$Adpative
public com.alibaba.dubbo.rpc.Invoker getInvoker(java.lang.Object arg0, java.lang.Class arg1, com.alibaba.dubbo.common.URL arg2) throws com.alibaba.dubbo.rpc.RpcException {
if (arg2 == null) throw new IllegalArgumentException("url == null");
com.alibaba.dubbo.common.URL url = arg2;
String extName = url.getParameter("proxy", "javassist");
if (extName == null)
throw new IllegalStateException("Fail to get extension(com.alibaba.dubbo.rpc.ProxyFactory) name from url(" + url.toString() + ") use keys([proxy])");
com.alibaba.dubbo.rpc.ProxyFactory extension = (com.alibaba.dubbo.rpc.ProxyFactory) ExtensionLoader.getExtensionLoader(com.alibaba.dubbo.rpc.ProxyFactory.class).getExtension(extName);
return extension.getInvoker(arg0, arg1, arg2);
}
這段代碼需要先說明下
因?yàn)榻涌赑roxyFactory下
@Adaptive({Constants.PROXY_KEY})
<T> Invoker<T> getInvoker(T proxy, Class<T> type, URL url) throws RpcException;
故而該方法是通過動(dòng)態(tài)編譯的方式去實(shí)現(xiàn)的
StubProxyFactoryWrapper.getInvoker
public <T> Invoker<T> getInvoker(T proxy, Class<T> type, URL url) throws RpcException {
return proxyFactory.getInvoker(proxy, type, url);
}
JavassistProxyFactory.getInvoker
public <T> Invoker<T> getInvoker(T proxy, Class<T> type, URL url) {
// TODO Wrapper類不能正確處理帶$的類名
final Wrapper wrapper = Wrapper.getWrapper(proxy.getClass().getName().indexOf('$') < 0 ? proxy.getClass() : type);
return new AbstractProxyInvoker<T>(proxy, type, url) {
@Override
protected Object doInvoke(T proxy, String methodName,
Class<?>[] parameterTypes,
Object[] arguments) throws Throwable {
return wrapper.invokeMethod(proxy, methodName, parameterTypes, arguments);
}
};
}
Wrapper.getWrapper
public static Wrapper getWrapper(Class<?> c) {
while (ClassGenerator.isDynamicClass(c)) // can not wrapper on dynamic class.
c = c.getSuperclass();
if (c == Object.class)
return OBJECT_WRAPPER;
Wrapper ret = WRAPPER_MAP.get(c);
if (ret == null) {
ret = makeWrapper(c);
WRAPPER_MAP.put(c, ret);
}
return ret;
}
Wrapper.makeWrapper(Class<?> c)//該方法主要是用來實(shí)現(xiàn)類的包裝對(duì)象Wrapper
其中傳入?yún)?shù) Class<?> c即為接口實(shí)現(xiàn)類的Class對(duì)象 绒疗，例如下面
com.alibaba.dubbo.demo.provider.DemoServiceImpl
二、invoker轉(zhuǎn)為exporter
private void exportLocal(URL url) {
if (!Constants.LOCAL_PROTOCOL.equalsIgnoreCase(url.getProtocol())) {
URL local = URL.valueOf(url.toFullString())
.setProtocol(Constants.LOCAL_PROTOCOL)
.setHost(NetUtils.LOCALHOST)
.setPort(0);
Exporter<?> exporter = protocol.export(
proxyFactory.getInvoker(ref, (Class) interfaceClass, local));
exporters.add(exporter);
logger.info("Export dubbo service " + interfaceClass.getName() + " to local registry");
}
}
其中
protocol.export(proxyFactory.getInvoker(ref, (Class) interfaceClass, local));
拆成兩個(gè)步驟就是
- Invoker invoker=proxyFactory.getInvoker(ref, (Class) interfaceClass, local)
- protocol.export(invoker)
接下來我們來看protocol.export(invoker)是如何將invoker轉(zhuǎn)為exporter
protocol.export(invoker)這一步debug進(jìn)去后為
Protocol$Adpative.export//這也是動(dòng)態(tài)編譯生產(chǎn)的類
public com.alibaba.dubbo.rpc.Exporter export(com.alibaba.dubbo.rpc.Invoker arg0) throws com.alibaba.dubbo.rpc.RpcException {
if (arg0 == null) throw new IllegalArgumentException("com.alibaba.dubbo.rpc.Invoker argument == null");
if (arg0.getUrl() == null)
throw new IllegalArgumentException("com.alibaba.dubbo.rpc.Invoker argument getUrl() == null");
com.alibaba.dubbo.common.URL url = arg0.getUrl();
String extName = (url.getProtocol() == null ? "dubbo" : url.getProtocol());
if (extName == null)
throw new IllegalStateException("Fail to get extension(com.alibaba.dubbo.rpc.Protocol) name from url(" + url.toString() + ") use keys([protocol])");
com.alibaba.dubbo.rpc.Protocol extension = (com.alibaba.dubbo.rpc.Protocol) ExtensionLoader.getExtensionLoader(com.alibaba.dubbo.rpc.Protocol.class).getExtension(extName);
return extension.export(arg0);
}
ProtocolFilterWrapper.export
public <T> Exporter<T> export(Invoker<T> invoker) throws RpcException {
if (Constants.REGISTRY_PROTOCOL.equals(invoker.getUrl().getProtocol())) {
return protocol.export(invoker);
}
return protocol.export(buildInvokerChain(invoker, Constants.SERVICE_FILTER_KEY, Constants.PROVIDER));
}
ProtocolFilterWrapper.buildInvokerChain
private static <T> Invoker<T> buildInvokerChain(final Invoker<T> invoker, String key, String group) {
Invoker<T> last = invoker;
List<Filter> filters = ExtensionLoader.getExtensionLoader(Filter.class).getActivateExtension(invoker.getUrl(), key, group);
if (filters.size() > 0) {
for (int i = filters.size() - 1; i >= 0; i--) {
final Filter filter = filters.get(i);
final Invoker<T> next = last;
last = new Invoker<T>() {
public Class<T> getInterface() {
return invoker.getInterface();
}
public URL getUrl() {
return invoker.getUrl();
}
public boolean isAvailable() {
return invoker.isAvailable();
}
public Result invoke(Invocation invocation) throws RpcException {
return filter.invoke(next, invocation);
}
public void destroy() {
invoker.destroy();
}
@Override
public String toString() {
return invoker.toString();
}
};
}
}
return last;
}
ProtocolListenerWrapper.export
public <T> Exporter<T> export(Invoker<T> invoker) throws RpcException {
if (Constants.REGISTRY_PROTOCOL.equals(invoker.getUrl().getProtocol())) {
return protocol.export(invoker);
}
return new ListenerExporterWrapper<T>(protocol.export(invoker),
Collections.unmodifiableList(ExtensionLoader.getExtensionLoader(ExporterListener.class)
.getActivateExtension(invoker.getUrl(), Constants.EXPORTER_LISTENER_KEY)));
}
InjvmProtocol.export
public <T> Exporter<T> export(Invoker<T> invoker) throws RpcException {
//目的：exporterMap.put(key, this)//key=com.alibaba.dubbo.demo.DemoService, this=InjvmExporter
return new InjvmExporter<T>(invoker, invoker.getUrl().getServiceKey(), exporterMap);
}
