Dynamic Proxy Review
- Almost all Java-related frameworks require dynamic proxy tools; 【 Personal understanding has the following two points 】
- Strongly typed: Java is a strongly typed language with type detection at compile time
- Faceted programming: Before, after user code execution… Weave into common processing logic
- The JDK dynamic Proxy classes have related Java. Lang. Reflect the Proxy, Java. Lang. Reflect. InvocationHandler
- To create a Proxy class, the JDK implements the InvocationHandler interface, which is used as a parameter to further create the corresponding Proxy class
- InvocationHandler: Object invoke(Object Proxy, Method Method, Object[] args) there is only one interface Method, usually we just need to implement the Method, not explicitly called, proxy Object will call this Method
- Proxy: nested objects such as proxy1 -> proxy2 ->… -> originObject
- When the proxy object method is called, the InvocationHandler#invoke method is called
- JDK dynamic proxies require interface definitions; A Javassist or ASM component can have no interface
- Dynamic proxy related document links
An overview of the
- Dubbo provides dynamic proxy factories including JdkProxyFactory and JavassistProxyFactory
- As you can see from the @spi annotation of the ProxyFactory interface, the default implementation is JavassistProxyFactory
- The core classes for generating Proxy class files using Javassist are Proxy, Wrapper
The role and necessity of dubbo dynamic proxy layer
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The RPC calls in the figure do not draw serialization, network layer… 【 Abstract 】
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Proxy-client, proxy-server only refers to the proxy layer in RPC framework. A number of proxy objects can be created
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The client and server are usually deployed on different servers, so the interface invocation and implementation needs to send network requests
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When the client invokes the RPC method:
- You can explicitly call each method of the RPC interface, actually calling the method of the proxy class.
- Method is usually broken down into classes, method names, parameters, return value types… Data such as
- Any interface method in proxy is nothing more than className, methodName, paramType, paramValue… Such data;
- From the specific interface method –> proxy object method –> encapsulation method data is req –> Send REq
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When the server receives the RPC method request:
- Parse reQ method data and create corresponding proxy objects;
- Why not create a concrete RPC interface implementation class object? Framework code can not call the method of the concrete implementation class, can only call the method of Proxy class;
- Proxy uses reflection to reference concrete implementation classes at user code runtime
- Receive REq –> parse REQ data –> proxy object –> interface implementation class
Dubbo dynamic proxy
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ProxyFactory uses JavassistProxyFactory by default
@SPI("javassist") public interface ProxyFactory { // This method is called more often in the service reference phase. // If called in the service reference phase, you usually need to create the corresponding Invoker instance based on the reference RPC interface // Create an unnormalized invocation proxy object @Adaptive({PROXY_KEY}) <T> T getProxy(Invoker<T> invoker) throws RpcException; // This method is called more often in the service reference phase. // If called in the service reference phase, you usually need to create the corresponding Invoker instance based on the reference RPC interface // generic: controls whether a proxy object is instantiated @Adaptive({PROXY_KEY}) <T> T getProxy(Invoker<T> invoker, boolean generic) throws RpcException; // This method is called more often in the service exposure phase. // proxy: RPC interface implementation class, or other... @Adaptive({PROXY_KEY}) <T> Invoker<T> getInvoker(T proxy, Class<T> type, URL url) throws RpcException; } Copy the code -
JavassistProxyFactory has two core classes, Proxy, Wrapper
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Note Proxy. GetProxy (interfaces). NewInstance (new InvokerInvocationHandler (invoker)); The return value is not a Proxy type
public class JavassistProxyFactory extends AbstractProxyFactory { @Override public <T> T getProxy(Invokerinvoker, Class [] interfaces) { Proxy#getProxy returns a Proxy object // Pass invoker in newInstance. / / [key] to generate specific Proxy objects (concrete Proxy class ClassType not org.apache.dubbo.com mon. The bytecode, Proxy 】 return (T) Proxy.getProxy(interfaces).newInstance(new InvokerInvocationHandler(invoker)); } @Override public <T> Invoker<T> getInvoker(T proxy, Class<T> type, URL url) { // Create the Wrapper class. final Wrapper wrapper = Wrapper.getWrapper(proxy.getClass().getName().indexOf('$') < 0 ? proxy.getClass() : type); // Create the Invoker object, which needs to be passed to proxy [e.g. RPC interface implementation class] return new AbstractProxyInvoker<T>(proxy, type, url) { // Invoke Object (Object proxy, Method Method, Object[] args) @Override protected Object doInvoke(T proxy, String methodName, Class [] parameterTypes, Object[] arguments) throws Throwable { // AbstractProxyInvoker#invoke calls the doInvoke method // the doInvoke method calls wrapper#invokeMethod // the wrapper#invokeMethod method calls the corresponding proxy method returnwrapper.invokeMethod(proxy, methodName, parameterTypes, arguments); }}; }}Copy the code
Dubbo Wrapper proxy class creation analysis
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The testDemoProtocol method requires invoker to execute the protocol.export(invoker) method
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This invoker is created using proxyFactory.getInvoker(***).
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The JavassistProxyFactory#getInvoker method is called by default; Call the Wrapper-related methods further
public class DubboProtocolTest { private Protocol protocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension(); private ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension(); @Test public void testDemoProtocol(a) throws Exception { // Interface implementation object DemoService service = new DemoServiceImpl(); int port = NetUtils.getAvailablePort(); // Parsing entry: service exposure phase call Proxy#getInvoker [with exceptions] protocol.export(proxyFactory.getInvoker(service, DemoService.class, URL.valueOf("Dubbo: / / 127.0.0.1." + port + "/" + DemoService.class.getName() + "? codec=exchange"))); service = proxyFactory.getProxy(protocol.refer(DemoService.class, URL.valueOf("Dubbo: / / 127.0.0.1." + port + "/" + DemoService.class.getName() + "? codec=exchange").addParameter("timeout".3000L))); assertEquals(service.getSize(new String[]{""."".""}), 3); }... }Copy the code
org.apache.dubbo.common.bytecode.Wrapper
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Proxy.getinvoker (***) executes the Wrapper#getWrapper method
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Wrapper#makeWrapper primarily calls the javassist API to generate dynamic proxy classes
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Debug to cc.toclass () manually run cc.mctc.writefile (“/doc”); You will see the Wrapper*.class file in the /doc/** directory
public abstract class Wrapper { private static finalMap<Class<? >, Wrapper> WRAPPER_MAP =newConcurrentHashMap<Class<? >, Wrapper>();//class wrapper map private static final String[] EMPTY_STRING_ARRAY = new String[0]; private static final String[] OBJECT_METHODS = new String[]{"getClass"."hashCode"."toString"."equals"}; private static AtomicLong WRAPPER_CLASS_COUNTER = new AtomicLong(0); // The argument object Class here is usually the Class of the propped object public static Wrapper getWrapper(Class c) { // If the proxy type is already dynamic while (ClassGenerator.isDynamicClass(c)) // can not wrapper on dynamic class. { c = c.getSuperclass(); } if (c == Object.class) { return OBJECT_WRAPPER; } // There will be a cache return WRAPPER_MAP.computeIfAbsent(c, key -> makeWrapper(key)); } // Create the dynamic proxy Wrapper class // Call the Javassist utility class to generate a class file. This method is very long. // Those interested in the Javassist API can read the source code 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 = ClassUtils.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($1 ")); }catch(Throwable e){ throw new IllegalArgumentException(e); }"); Map<String, Class<? >> pts =new HashMap<>(); // <property name, property types> Map<String, Method> ms = new LinkedHashMap<>(); // <method desc, Method instance> List<String> mns = new ArrayList<>(); // method names. List<String> dmns = new ArrayList<>(); // declaring method names. for(map.entry <String, Method> Entry: Ms. EntrySet ()) {... }long id = WRAPPER_CLASS_COUNTER.getAndIncrement(); ClassGenerator cc = ClassGenerator.newInstance(cl); // Dynamic proxy class names are usually Wrapper0, Wrapper1... // The dynamic proxy class is in the same package as the Wrapper cc.setClassName((Modifier.isPublic(c.getModifiers()) ? Wrapper.class.getName() : c.getName() + "$sw") + id); // The dynamic proxy class extends Wrapper cc.setSuperClass(Wrapper.class); try { // Generate the Class Class // debug to run cc.mctc.writefile ("/doc"); Can generate dynamic proxy class file decompilation can see the corresponding codeClass<? > 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(); }}//final Wrapper wrapper = Wrapper.getWrapper(proxy.getClass()); Will implement this class // instance abstract public Object invokeMethod(Object instance, String mn, Class [] types, Object[] args) throws NoSuchMethodException, InvocationTargetException; } Copy the code
Dynamic proxy file wrapper0.class created from Wrapper
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Wrapper0 is a class generated by calling wrapper.getwrapper (DemoServicePl.class). This method is usually called during service exposure to uniformly convert all RPC interface implementation classes into subclasses of Wrapper.
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Within each method in Wrapper0, there is a line of code that converts the parameter to type DemoServiceImpl
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In the proxy class instance [e.g., Wrapper0] and proxy class instance creation phase only need to pass in the class type of the proxied object; [Formal parameters]
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Wrapper0#invokeMethod (); Wrapper0#invokeMethod
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Wrapper0 does not have the proxied object instance as an attribute; A Proxy generates a Proxy object that has instances of the proxied object as properties
// In the same package as the Wrapper package org.apache.dubbo.common.bytecode; import java.lang.reflect.InvocationTargetException; import java.util.Map; import org.apache.dubbo.rpc.protocol.dubbo.support.CustomArgument; import org.apache.dubbo.rpc.protocol.dubbo.support.DemoServiceImpl; import org.apache.dubbo.rpc.protocol.dubbo.support.Man; import org.apache.dubbo.rpc.protocol.dubbo.support.NonSerialized; import org.apache.dubbo.rpc.protocol.dubbo.support.Person; import org.apache.dubbo.rpc.protocol.dubbo.support.Type; // Implement the classGenerator. DC interface to indicate that Wrapper0 is a dynamic proxy class 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 static Class[] mts1; public static Class[] mts2; public static Class[] mts3; public static Class[] mts4; public static Class[] mts5; public static Class[] mts6; public static Class[] mts7; public static Class[] mts8; public static Class[] mts9; public static Class[] mts10; public static Class[] mts11; public static Class[] mts12; public static Class[] mts13; public static Class[] mts14; public static Class[] mts15; public static Class[] mts16; public static Class[] mts17; public static Class[] mts18; public static Class[] mts19; public static Class[] mts20; public static Class[] mts21; 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 { DemoServiceImpl demoServiceImpl = (DemoServiceImpl)paramObject1; } catch (Throwable throwable) { throw new IllegalArgumentException(throwable); } throw new NoSuchPropertyException("Not found property \"" + paramString + "\" field or setter method in class org.apache.dubbo.rpc.protocol.dubbo.support.DemoServiceImpl."); } public Object getPropertyValue(Object paramObject, String paramString) { DemoServiceImpl demoServiceImpl; try { demoServiceImpl = (DemoServiceImpl)paramObject; } catch (Throwable throwable) { throw new IllegalArgumentException(throwable); } if (paramString.equals("threadName")) return demoServiceImpl.getThreadName(); if (paramString.equals("remoteApplicationName")) return demoServiceImpl.getRemoteApplicationName(); throw new NoSuchPropertyException("Not found property \"" + paramString + "\" field or setter method in class org.apache.dubbo.rpc.protocol.dubbo.support.DemoServiceImpl."); } // All DemoService method call entries public Object invokeMethod(Object paramObject, String paramString, Class[] paramArrayOfClass, Object[] paramArrayOfObject) throws InvocationTargetException { // Execute to wrapper.getwrapper (demoServiceImpl.class); // All methods in Wrapper0 call the demoServiceImpl method internally DemoServiceImpl demoServiceImpl; try { demoServiceImpl = (DemoServiceImpl)paramObject; } catch (Throwable throwable) { throw new IllegalArgumentException(throwable); } // See this string if else also slightly drunk // All methods of the DemoService interface are in the following method names // The options are EchoService and Destroyable // AbstractProxyFactory has code to add *EchoService, Destroyable* try { if (!"invoke".equals(paramString) || paramArrayOfClass.length ! =2) { if (!"add".equals(paramString) || paramArrayOfClass.length ! =2) { if (!"get".equals(paramString) || paramArrayOfClass.length ! =1) { if (!"getInt".equals(paramString) || paramArrayOfClass.length ! =1) { if (!"timestamp".equals(paramString) || paramArrayOfClass.length ! =0) { if (!"keys".equals(paramString) || paramArrayOfClass.length ! =1) { if (!"getType".equals(paramString) || paramArrayOfClass.length ! =1) { if (!"getSize".equals(paramString) || paramArrayOfClass.length ! =1| |! paramArrayOfClass[0].getName().equals("[Ljava.lang.Object;")) { if (!"getSize".equals(paramString) || paramArrayOfClass.length ! =1| |! paramArrayOfClass[0].getName().equals("[Ljava.lang.String;")) { if (!"getPerson".equals(paramString) || paramArrayOfClass.length ! =2| |! paramArrayOfClass[0].getName().equals("org.apache.dubbo.rpc.protocol.dubbo.support.Person") | |! paramArrayOfClass[1].getName().equals("org.apache.dubbo.rpc.protocol.dubbo.support.Person")) { if (!"getPerson".equals(paramString) || paramArrayOfClass.length ! =1| |! paramArrayOfClass[0].getName().equals("org.apache.dubbo.rpc.protocol.dubbo.support.Man")) { if (!"getPerson".equals(paramString) || paramArrayOfClass.length ! =1| |! paramArrayOfClass[0].getName().equals("org.apache.dubbo.rpc.protocol.dubbo.support.Person")) { if (!"getThreadName".equals(paramString) || paramArrayOfClass.length ! =0) { if (!"echo".equals(paramString) || paramArrayOfClass.length ! =1| |! paramArrayOfClass[0].getName().equals("java.lang.String")) { if (!"echo".equals(paramString) || paramArrayOfClass.length ! =1| |! paramArrayOfClass[0].getName().equals("java.util.Map")) { if (!"enumlength".equals(paramString) || paramArrayOfClass.length ! =1) { if (!"stringLength".equals(paramString) || paramArrayOfClass.length ! =1) { if (!"sayHello".equals(paramString) || paramArrayOfClass.length ! =1) { if (!"nonSerializedParameter".equals(paramString) || paramArrayOfClass.length ! =1) { if (!"returnNonSerialized".equals(paramString) || paramArrayOfClass.length ! =0) { if (!"getRemoteApplicationName".equals(paramString) || paramArrayOfClass.length ! =0) { if (!"gerPerson".equals(paramString) || paramArrayOfClass.length ! =1) throw new NoSuchMethodException("Not found method \"" + paramString + "\" in class org.apache.dubbo.rpc.protocol.dubbo.support.DemoServiceImpl."); return demoServiceImpl.gerPerson((Person)paramArrayOfObject[0]); } return demoServiceImpl.getRemoteApplicationName(); } return demoServiceImpl.returnNonSerialized(); } demoServiceImpl.nonSerializedParameter((NonSerialized)paramArrayOfObject[0]); return null; } demoServiceImpl.sayHello((String)paramArrayOfObject[0]); return null; } new Integer(); super(new Integer()); return new Integer(); } return demoServiceImpl.enumlength((Type[])paramArrayOfObject[0]); } return demoServiceImpl.echo((Map)paramArrayOfObject[0]); } return demoServiceImpl.echo((String)paramArrayOfObject[0]); } return demoServiceImpl.getThreadName(); } new Integer(); super(new Integer()); return new Integer(); } return demoServiceImpl.getPerson((Man)paramArrayOfObject[0]); } new Integer(); super(new Integer()); return new Integer(); } new Integer(); super(new Integer()); return new Integer(); } new Integer(); super(new Integer()); return new Integer(); } return demoServiceImpl.getType((Type)paramArrayOfObject[0]); } return demoServiceImpl.keys((Map)paramArrayOfObject[0]); } new Long(); super(new Long()); return new Long(); } new Integer(); super(new Integer()); return new Integer(); } return demoServiceImpl.get((CustomArgument)paramArrayOfObject[0]); } new Long(); super(new Long()); return new Long(); } return demoServiceImpl.invoke((String)paramArrayOfObject[0], (String)paramArrayOfObject[1]); } catch (Throwable throwable) { throw newInvocationTargetException(throwable); }}}Copy the code
Dubbo Proxy Proxy class creation analysis
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The testDemoProtocol method calls protocol.refer(***) to generate the Invoke object
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proxyFactory#getProxy –> Proxy.getProxy(interfaces).newInstance(new InvokerInvocationHandler(invoker));
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Invoke is called proxyFactory.getProxy(invoke) as a proxied object to generate a proxy object.
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Proxy.getproxy (interfaces) returns a subclass of Proxy,
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NewInstance (New InvokerInvocationHandler(invoker)); The return value is the implementation class of the concrete interface
public class DubboProtocolTest { private Protocol protocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension(); private ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension(); @Test public void testDemoProtocol(a) throws Exception { DemoService service = new DemoServiceImpl(); int port = NetUtils.getAvailablePort(); protocol.export(proxyFactory.getInvoker(service, DemoService.class, URL.valueOf("Dubbo: / / 127.0.0.1." + port + "/" + DemoService.class.getName() + "? codec=exchange"))); // analysis entry: proxyFactory#getProxy is invoked in the service reference phase. service = proxyFactory.getProxy(protocol.refer(DemoService.class, URL.valueOf("Dubbo: / / 127.0.0.1." + port + "/" + DemoService.class.getName() + "? codec=exchange").addParameter("timeout".3000L))); assertEquals(service.getSize(new String[]{""."".""}), 3); }... }Copy the code
org.apache.dubbo.common.bytecode.Proxy
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Entry method: Proxy#getProxy
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Proxy also uses Javassist to generate Proxy objects
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Proxy# getProxy call mon org.apache.dubbo.com. There are two times in the bytecode. ClassGenerator# toClass (); Ccp.toclass (); and ccm.toclass ();
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Calling toClass twice is one of the easier areas to confuse the reader
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Pay attention to the CCP. ToClass is org.apache.dubbo.com mon. The bytecode. Proxy0 type “lowercase p”
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Note that CCM toClass is org.apache.dubbo.com mon. The bytecode. Proxy0 type [uppercase P]
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Debug toClass manually execute ccm.mctc.writefile (“/doc”); ccp.mCtc.writeFile(“/doc”); The corresponding class file can be generated
public abstract class Proxy { private static final AtomicLong PROXY_CLASS_COUNTER = new AtomicLong(0); private static final String PACKAGE_NAME = Proxy.class.getPackage().getName(); // The proxy generates the cache private static final Map<ClassLoader, Map<String, Object>> PROXY_CACHE_MAP = new WeakHashMap<ClassLoader, Map<String, Object>>(); private static final Object PENDING_GENERATION_MARKER = new Object(); protected Proxy(a) {}.../** * Get proxy. * * @param ics interface class array. * @return Proxy instance. */ public static Proxy getProxy(Class ... ics) { return getProxy(ClassUtils.getClassLoader(Proxy.class), ics); } public static Proxy getProxy(ClassLoader cl, Class ... ics) { if (ics.length > MAX_PROXY_COUNT) { throw new IllegalArgumentException("interface limit exceeded"); } StringBuilder sb = new StringBuilder(); for (int i = 0; i < ics.length; I++) {... }// use interface class name list as key. String key = sb.toString(); // get cache by class loader. final Map<String, Object> cache; synchronized (PROXY_CACHE_MAP) { cache = PROXY_CACHE_MAP.computeIfAbsent(cl, k -> new HashMap<>()); } Proxy proxy = null; long id = PROXY_CLASS_COUNTER.getAndIncrement(); String pkg = null; ClassGenerator ccp = null, ccm = null; try { ccp = ClassGenerator.newInstance(cl); Set<String> worked = new HashSet<>(); List<Method> methods = new ArrayList<>(); if (pkg == null) { pkg = PACKAGE_NAME; }...// The most confusing piece of code // what is the relationship between CCP and CCM / / CCP. Mon toClass is org.apache.dubbo.com. The bytecode. Proxy0 type "lowercase p" / / CCM. Mon toClass is org.apache.dubbo.com. The bytecode. Proxy0 type [uppercase P] // CCP only has definitions, but is not returned or referenced. / / CCP. Actually means org.apache.dubbo.com mon toClass method. The bytecode. Proxy0 class has been the class loader loads CCM and CCP are only associated with the PCN class name string. / / CCM. ToClass executes the PCN to check the org.apache.dubbo.com mon. The bytecode. Proxy0 】 exists // create ProxyInstance class. String pcn = pkg + ".proxy" + id; // ccp: org.apache.dubbo.common.bytecode.proxy0 ccp.setClassName(pcn); ccp.addField("public static java.lang.reflect.Method[] methods;"); ccp.addField("private " + InvocationHandler.class.getName() + " handler;"); ccp.addConstructor(Modifier.PUBLIC, newClass<? >[]{InvocationHandler.class},newClass<? > [0]."handler=$1;"); ccp.addDefaultConstructor(); Class<? > clazz = ccp.toClass(); clazz.getField("methods").set(null, methods.toArray(new Method[0])); // create Proxy class. String fcn = Proxy.class.getName() + id; ccm = ClassGenerator.newInstance(cl); ccm.setClassName(fcn); ccm.addDefaultConstructor(); ccm.setSuperClass(Proxy.class); ccm.addMethod("public Object newInstance(" + InvocationHandler.class.getName() + " h){ return new " + pcn + "($1); }"); Class<? > pc = ccm.toClass(); proxy = (Proxy) pc.newInstance(); }catch (RuntimeException e) { throw e; } catch (Exception e) { throw new RuntimeException(e.getMessage(), e); } finally { // release ClassGenerator if(ccp ! =null) { ccp.release(); } if(ccm ! =null) { ccm.release(); } synchronized (cache) { if (proxy == null) { cache.remove(key); } else { cache.put(key, newWeakReference<Proxy>(proxy)); } cache.notifyAll(); }}return proxy; } // Create a proxy class that implements this interface // handler: proxied object abstract public Object newInstance(InvocationHandler handler); } Copy the code
Create dynamic Proxy file proxy0.class
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Proxy0 is a subclass of Proxy with an abstract implementation method: Proxy#newInstance
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Ccm.toclass () generates Proxy0 by requiring the presence of Proxy0
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Proxy0 can be seen as a factory for Proxy0
/******* caller code **********/ @Override @SuppressWarnings("unchecked") public <T> T getProxy(Invokerinvoker, Class [] interfaces) { // proxy.getProxy (interfaces) returns Proxy0 // interfaces will return proxy0 return (T) Proxy.getProxy(interfaces).newInstance(new InvokerInvocationHandler(invoker)); } / * * * * * * * * * * * * * * * * * / / / Proxy0 code package org.apache.dubbo.common.bytecode; import java.lang.reflect.InvocationHandler; public class Proxy0 extends Proxy implements ClassGenerator.DC { public Object newInstance(InvocationHandler paramInvocationHandler) { // return proxy0 [interfaces] return newproxy0(paramInvocationHandler); }}Copy the code
Create dynamic Proxy file proxy0.class
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Proxy0 holds the attribute InvocationHandler
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InvocationHandler holds the Invoker attribute.
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Proxy0 is the implementation class of DemoService
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InvocationHandler –> Invoker
package org.apache.dubbo.common.bytecode; import com.alibaba.dubbo.rpc.service.EchoService; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import java.util.Map; import java.util.Set; import org.apache.dubbo.rpc.protocol.dubbo.support.CustomArgument; import org.apache.dubbo.rpc.protocol.dubbo.support.DemoService; import org.apache.dubbo.rpc.protocol.dubbo.support.Man; import org.apache.dubbo.rpc.protocol.dubbo.support.NonSerialized; import org.apache.dubbo.rpc.protocol.dubbo.support.Person; import org.apache.dubbo.rpc.protocol.dubbo.support.Type; import org.apache.dubbo.rpc.service.Destroyable; public class proxy0 implements ClassGenerator.DC.Destroyable.DemoService.EchoService { public static Method[] methods; private InvocationHandler handler; public Object $echo(Object paramObject) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramObject; Object object = this.handler.invoke(this, methods[0], arrayOfObject); return (Object)object; } public void $destroy() { Object[] arrayOfObject = new Object[0]; Object object = this.handler.invoke(this, methods[1], arrayOfObject); } public Object invoke(String paramString1, String paramString2) throws Exception { Object[] arrayOfObject = new Object[2]; arrayOfObject[0] = paramString1; arrayOfObject[1] = paramString2; Object object = this.handler.invoke(this, methods[2], arrayOfObject); return (Object)object; } public long add(int paramInt, long paramLong) { Object[] arrayOfObject = new Object[2]; new Integer(); super(new Integer()); false[new Integer()] = new Integer(); new Long(); super(new Long()); true[new Long()] = new Long(); Object object = this.handler.invoke(this, methods[3], arrayOfObject); return (object == null)?false : ((Long)object).longValue(); } public String get(CustomArgument paramCustomArgument) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramCustomArgument; Object object = this.handler.invoke(this, methods[4], arrayOfObject); return (String)object; } public int getInt(int paramInt) { Object[] arrayOfObject = new Object[1]; new Integer(); super(new Integer()); false[new Integer()] = new Integer(); Object object = this.handler.invoke(this, methods[5], arrayOfObject); return (object == null)?0 : ((Integer)object).intValue(); } public long timestamp(a) { Object[] arrayOfObject = new Object[0]; Object object = this.handler.invoke(this, methods[6], arrayOfObject); return (object == null)?false : ((Long)object).longValue(); } public Set keys(Map paramMap) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramMap; Object object = this.handler.invoke(this, methods[7], arrayOfObject); return (Set)object; } public Type getType(Type paramType) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramType; Object object = this.handler.invoke(this, methods[8], arrayOfObject); return (Type)object; } public int getSize(Object[] paramArrayOfObject) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramArrayOfObject; Object object = this.handler.invoke(this, methods[9], arrayOfObject); return (object == null)?0 : ((Integer)object).intValue(); } public int getSize(String[] paramArrayOfString) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramArrayOfString; Object object = this.handler.invoke(this, methods[10], arrayOfObject); return (object == null)?0 : ((Integer)object).intValue(); } public void sayHello(String paramString) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramString; Object object = this.handler.invoke(this, methods[11], arrayOfObject); } public Map echo(Map paramMap) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramMap; Object object = this.handler.invoke(this, methods[12], arrayOfObject); return (Map)object; } public String echo(String paramString) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramString; Object object = this.handler.invoke(this, methods[13], arrayOfObject); return (String)object; } public Type enumlength(Type[] paramArrayOfType) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramArrayOfType; Object object = this.handler.invoke(this, methods[14], arrayOfObject); return (Type)object; } public int stringLength(String paramString) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramString; Object object = this.handler.invoke(this, methods[15], arrayOfObject); return (object == null)?0 : ((Integer)object).intValue(); } public void nonSerializedParameter(NonSerialized paramNonSerialized) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramNonSerialized; Object object = this.handler.invoke(this, methods[16], arrayOfObject); } public NonSerialized returnNonSerialized(a) { Object[] arrayOfObject = new Object[0]; Object object = this.handler.invoke(this, methods[17], arrayOfObject); return (NonSerialized)object; } public String getRemoteApplicationName(a) { Object[] arrayOfObject = new Object[0]; Object object = this.handler.invoke(this, methods[18], arrayOfObject); return (String)object; } public String getPerson(Man paramMan) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramMan; Object object = this.handler.invoke(this, methods[19], arrayOfObject); return (String)object; } public int getPerson(Person paramPerson1, Person paramPerson2) { Object[] arrayOfObject = new Object[2]; arrayOfObject[0] = paramPerson1; arrayOfObject[1] = paramPerson2; Object object = this.handler.invoke(this, methods[20], arrayOfObject); return (object == null)?0 : ((Integer)object).intValue(); } public int getPerson(Person paramPerson) { Object[] arrayOfObject = new Object[1]; arrayOfObject[0] = paramPerson; Object object = this.handler.invoke(this, methods[21], arrayOfObject); return (object == null)?0 : ((Integer)object).intValue(); } public String getThreadName(a) { Object[] arrayOfObject = new Object[0]; Object object = this.handler.invoke(this, methods[22], arrayOfObject); return (String)object; } public proxy0(a) {} public proxy0(InvocationHandler paramInvocationHandler) { this.handler = paramInvocationHandler; }}Copy the code
Wrapper and Proxy differences
- Wrapper only generated proxy class Wrapper*
- Proxy generates a Proxy* [Proxy subclass], Proxy* [interface implementation class]
- Wrapper* is a proxy for the proxied object, but does not hold properties of the proxied object
- Proxy* is not a Proxy for the propped object, but can be created using the newInstance method
- Proxy * is the proxy of the proxied object and holds the properties of the proxied object
- The service caller must have a process to create the corresponding Proxy * [RPC interface implementation class Proxy] object through Proxy; Because the user code needs to explicitly call the interface methods
- Wrapper * does not implement any interface and therefore cannot be explicitly called, usually within the framework using a method call to convert any RPC interface implementation class into a unified object. [With exceptions]