dubbo起停之服务暴露
由上一节可知带上dubbo@Service注解的对象，在注册成为bean之后会进一步注册一个ServiceBean，服务暴露便是在这里
public void afterPropertiesSet() throws Exception { if (getProvider() == null) { Map<String, ProviderConfig> providerConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProviderConfig.class, false, false); if (providerConfigMap != null && providerConfigMap.size() > 0) { Map<String, ProtocolConfig> protocolConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProtocolConfig.class, false, false); if ((protocolConfigMap == null || protocolConfigMap.size() == 0) && providerConfigMap.size() > 1) { // backward compatibility List<ProviderConfig> providerConfigs = new ArrayList<ProviderConfig>(); for (ProviderConfig config : providerConfigMap.values()) { if (config.isDefault() != null && config.isDefault().booleanValue()) { providerConfigs.add(config); } } if (!providerConfigs.isEmpty()) { setProviders(providerConfigs); } } else { ProviderConfig providerConfig = null; for (ProviderConfig config : providerConfigMap.values()) { if (config.isDefault() == null || config.isDefault().booleanValue()) { if (providerConfig != null) { throw new IllegalStateException("Duplicate provider configs: " + providerConfig + " and " + config); } providerConfig = config; } } if (providerConfig != null) { setProvider(providerConfig); } } } }
......
if (getPath() == null || getPath().length() == 0) {
if (beanName != null && beanName.length() > 0
&& getInterface() != null && getInterface().length() > 0
&& beanName.startsWith(getInterface())) {
setPath(beanName);
}
}
if (!isDelay()) {
export();
}
}
protected synchronized void doExport() { if (unexported) { throw new IllegalStateException("Already unexported!"); } if (exported) { return; } exported = true; if (interfaceName == null || interfaceName.length() == 0) { throw new IllegalStateException("<dubbo:service interface=\"\" /> interface not allow null!"); } ...... checkApplication(); checkRegistry(); checkProtocol(); appendProperties(this); checkStubAndMock(interfaceClass); if (path == null || path.length() == 0) { path = interfaceName; } doExportUrls(); ProviderModel providerModel = new ProviderModel(getUniqueServiceName(), this, ref); ApplicationModel.initProviderModel(getUniqueServiceName(), providerModel); }
doExportUrlsFor1Protocol一进去有相当长的逻辑是在各配置对象里搜罗必要的配置信息，在具体的暴露服务的代码之前我们可以得到这样一个map：
接着是暴露服务的逻辑
注意这里有个扩展点，大致的过程是根据url取到物理ip和端口 并从url中根据scope判断是本地的服务还是远程，这里先不关心本地服务的暴露 看下非本地的情况：
在为url和registryURL填充若干属性之后，url便填充registryURL的export属性，registryURL作为参数通过代理工厂实例化一个invoker对象。在之后invoker和serviceBean一起作为参数，暴露服务
仔细看一下
Invoker<?> invoker = proxyFactory.getInvoker(ref, (Class) interfaceClass, registryURL.addParameterAndEncoded(Constants.EXPORT_KEY, url.toFullString()));
调试时的参数，各入参值如下：
proxy指向EchoServiceImpl的实例，type为接口Class类，url为
registry://localhost:2181/com.alibaba.dubbo.registry.RegistryService?application=echo-annotation-provider&dubbo=2.0.2&export=dubbo://10.1.81.210:20880/facade.EchoService?anyhost=true&application=echo-annotation-provider&bean.name=ServiceBean:facade.EchoService&bind.ip=10.1.81.210&bind.port=20880&dubbo=2.0.2&generic=false&interface=facade.EchoService&methods=echo&pid=84968&side=provider×tamp=1572767833008&pid=84968®istry=zookeeper×tamp=1572767833000
深入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为每个Class维护了一个WRAPPER_MAP缓存，如果没有命中则初始化makeWrapper(c)：
private static Wrapper makeWrapper(Class<?> c) { if (c.isPrimitive()) throw new IllegalArgumentException("Can not create wrapper for primitive type: " + c); String name = c.getName(); ClassLoader cl = ClassHelper.getClassLoader(c); StringBuilder c1 = new StringBuilder("public void setPropertyValue(Object o, String n, Object v){ "); StringBuilder c2 = new StringBuilder("public Object getPropertyValue(Object o, String n){ "); StringBuilder c3 = new StringBuilder("public Object invokeMethod(Object o, String n, Class[] p, Object[] v) throws " + InvocationTargetException.class.getName() + "{ "); c1.append(name).append(" w; try{ w = ((").append(name).append(")$1); }catch(Throwable e){ throw new IllegalArgumentException(e); }"); c2.append(name).append(" w; try{ w = ((").append(name).append(")$1); }catch(Throwable e){ throw new IllegalArgumentException(e); }"); c3.append(name).append(" w; try{ w = ((").append(name).append(")$1); }catch(Throwable e){ throw new IllegalArgumentException(e); }"); Map<String, Class<?>> pts = new HashMap<String, Class<?>>(); // <property name, property types> Map<String, Method> ms = new LinkedHashMap<String, Method>(); // <method desc, Method instance> List<String> mns = new ArrayList<String>(); // method names. List<String> dmns = new ArrayList<String>(); // declaring method names. // get all public field. for (Field f : c.getFields()) { String fn = f.getName(); Class<?> ft = f.getType(); if (Modifier.isStatic(f.getModifiers()) || Modifier.isTransient(f.getModifiers())) continue; c1.append(" if( $2.equals(\"").append(fn).append("\") ){ w.").append(fn).append("=").append(arg(ft, "$3")).append("; return; }"); c2.append(" if( $2.equals(\"").append(fn).append("\") ){ return ($w)w.").append(fn).append("; }"); pts.put(fn, ft); } Method[] methods = c.getMethods(); // get all public method. boolean hasMethod = hasMethods(methods); if (hasMethod) { c3.append(" try{"); } for (Method m : methods) { if (m.getDeclaringClass() == Object.class) //ignore Object's method. continue; String mn = m.getName(); c3.append(" if( \"").append(mn).append("\".equals( $2 ) "); int len = m.getParameterTypes().length; c3.append(" && ").append(" $3.length == ").append(len); boolean override = false; for (Method m2 : methods) { if (m != m2 && m.getName().equals(m2.getName())) { override = true; break; } } if (override) { if (len > 0) { for (int l = 0; l < len; l++) { c3.append(" && ").append(" $3[").append(l).append("].getName().equals(\"") .append(m.getParameterTypes()[l].getName()).append("\")"); } } } c3.append(" ) { "); if (m.getReturnType() == Void.TYPE) c3.append(" w.").append(mn).append('(').append(args(m.getParameterTypes(), "$4")).append(");").append(" return null;"); else c3.append(" return ($w)w.").append(mn).append('(').append(args(m.getParameterTypes(), "$4")).append(");"); c3.append(" }"); mns.add(mn); if (m.getDeclaringClass() == c) dmns.add(mn); ms.put(ReflectUtils.getDesc(m), m); } if (hasMethod) { c3.append(" } catch(Throwable e) { "); c3.append(" throw new java.lang.reflect.InvocationTargetException(e); "); c3.append(" }"); } c3.append(" throw new " + NoSuchMethodException.class.getName() + "(\"Not found method \\\"\"+$2+\"\\\" in class " + c.getName() + ".\"); }"); // deal with get/set method. Matcher matcher; for (Map.Entry<String, Method> entry : ms.entrySet()) { String md = entry.getKey(); Method method = (Method) entry.getValue(); if ((matcher = ReflectUtils.GETTER_METHOD_DESC_PATTERN.matcher(md)).matches()) { String pn = propertyName(matcher.group(1)); c2.append(" if( $2.equals(\"").append(pn).append("\") ){ return ($w)w.").append(method.getName()).append("(); }"); pts.put(pn, method.getReturnType()); } else if ((matcher = ReflectUtils.IS_HAS_CAN_METHOD_DESC_PATTERN.matcher(md)).matches()) { String pn = propertyName(matcher.group(1)); c2.append(" if( $2.equals(\"").append(pn).append("\") ){ return ($w)w.").append(method.getName()).append("(); }"); pts.put(pn, method.getReturnType()); } else if ((matcher = ReflectUtils.SETTER_METHOD_DESC_PATTERN.matcher(md)).matches()) { Class<?> pt = method.getParameterTypes()[0]; String pn = propertyName(matcher.group(1)); c1.append(" if( $2.equals(\"").append(pn).append("\") ){ w.").append(method.getName()).append("(").append(arg(pt, "$3")).append("); return; }"); pts.put(pn, pt); } } c1.append(" throw new " + NoSuchPropertyException.class.getName() + "(\"Not found property \\\"\"+$2+\"\\\" filed or setter method in class " + c.getName() + ".\"); }"); c2.append(" throw new " + NoSuchPropertyException.class.getName() + "(\"Not found property \\\"\"+$2+\"\\\" filed or setter method in class " + c.getName() + ".\"); }"); // make class long id = WRAPPER_CLASS_COUNTER.getAndIncrement(); ClassGenerator cc = ClassGenerator.newInstance(cl); cc.setClassName((Modifier.isPublic(c.getModifiers()) ? Wrapper.class.getName() : c.getName() + "$sw") + id); cc.setSuperClass(Wrapper.class); cc.addDefaultConstructor(); cc.addField("public static String[] pns;"); // property name array. cc.addField("public static " + Map.class.getName() + " pts;"); // property type map. cc.addField("public static String[] mns;"); // all method name array. cc.addField("public static String[] dmns;"); // declared method name array. for (int i = 0, len = ms.size(); i < len; i++) cc.addField("public static Class[] mts" + i + ";"); cc.addMethod("public String[] getPropertyNames(){ return pns; }"); cc.addMethod("public boolean hasProperty(String n){ return pts.containsKey($1); }"); cc.addMethod("public Class getPropertyType(String n){ return (Class)pts.get($1); }"); cc.addMethod("public String[] getMethodNames(){ return mns; }"); cc.addMethod("public String[] getDeclaredMethodNames(){ return dmns; }"); cc.addMethod(c1.toString()); cc.addMethod(c2.toString()); cc.addMethod(c3.toString()); try { Class<?> wc = cc.toClass(); // setup static field. wc.getField("pts").set(null, pts); wc.getField("pns").set(null, pts.keySet().toArray(new String[0])); wc.getField("mns").set(null, mns.toArray(new String[0])); wc.getField("dmns").set(null, dmns.toArray(new String[0])); int ix = 0; for (Method m : ms.values()) wc.getField("mts" + ix++).set(null, m.getParameterTypes()); return (Wrapper) wc.newInstance(); } catch (RuntimeException e) { throw e; } catch (Throwable e) { throw new RuntimeException(e.getMessage(), e); } finally { cc.release(); ms.clear(); mns.clear(); dmns.clear(); } }
我们修改源码试图将javasisst生成的代码导出：
mCtc.writeFile("/Users/lichengcheng/dubbo");
重新打包，可以看到生成的代理class如下：
package com.alibaba.dubbo.common.bytecode; import facade.EchoService; import java.lang.reflect.InvocationTargetException; import java.util.Map; public class Wrapper0 extends Wrapper implements ClassGenerator.DC { public static String[] pns; public static Map pts; public static String[] mns; public static String[] dmns; public static Class[] mts0; public String[] getPropertyNames() { return pns; } public boolean hasProperty(String paramString) { return pts.containsKey(paramString); } public Class getPropertyType(String paramString) { return (Class)pts.get(paramString); } public String[] getMethodNames() { return mns; } public String[] getDeclaredMethodNames() { return dmns; } public void setPropertyValue(Object paramObject1, String paramString, Object paramObject2) { try { EchoService localEchoService = (EchoService)paramObject1; } catch (Throwable localThrowable) { throw new IllegalArgumentException(localThrowable); } throw new NoSuchPropertyException("Not found property \"" + paramString + "\" filed or setter method in class facade.EchoService."); } public Object getPropertyValue(Object paramObject, String paramString) { try { EchoService localEchoService = (EchoService)paramObject; } catch (Throwable localThrowable) { throw new IllegalArgumentException(localThrowable); } throw new NoSuchPropertyException("Not found property \"" + paramString + "\" filed or setter method in class facade.EchoService."); } public Object invokeMethod(Object paramObject, String paramString, Class[] paramArrayOfClass, Object[] paramArrayOfObject) throws InvocationTargetException { EchoService localEchoService; try { localEchoService = (EchoService)paramObject; } catch (Throwable localThrowable1) { throw new IllegalArgumentException(localThrowable1); } try { if ((!"echo".equals(paramString)) || (paramArrayOfClass.length == 1)) { return localEchoService.echo((String)paramArrayOfObject[0]); } } catch (Throwable localThrowable2) { throw new InvocationTargetException(localThrowable2); } throw new NoSuchMethodException("Not found method \"" + paramString + "\" in class facade.EchoService."); } }
这里开始是一连串的拦截器，最后会到DubboProtocol#export暴露服务：
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