pfinder實(shí)現(xiàn)原理揭秘

   @Override        public void visitCode() {            super.visitCode();            mv.visitFieldInsn(GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");            mv.visitLdcInsn("start");            mv.visitMethodInsn(INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V", false);        }        @Override        public void visitInsn(int opcode) {            if ((opcode >= Opcodes.IRETURN && opcode <= Opcodes.RETURN) || opcode == Opcodes.ATHROW) {                //方法在返回之前，打印"end"                mv.visitFieldInsn(GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");                mv.visitLdcInsn("end");                mv.visitMethodInsn(INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V", false);            }            mv.visitInsn(opcode);        }

        ClassPool cp = ClassPool.getDefault();        CtClass cc = cp.get("com.ggc.javassist.HelloWord");        CtMethod m = cc.getDeclaredMethod("printHelloWord");        m.insertBefore("{ System.out.println(\"start\"); }");        m.insertAfter("{ System.out.println(\"end\"); }");        Class c = cc.toClass();        cc.writeFile("/Users/gonghanglin/workspace/workspace_me/bytecode_enhance/bytecode_enhance_javassist/target/classes/com/ggc/javassist");        HelloWord h = (HelloWord)c.newInstance();        h.printHelloWord();

   // 使用ByteBuddy動(dòng)態(tài)生成一個(gè)新的HelloWord類        Class<?> dynamicType = new ByteBuddy()                .subclass(HelloWord.class) // 指定要修改的類                .method(ElementMatchers.named("printHelloWord")) // 指定要攔截的方法名                .intercept(MethodDelegation.to(LoggingInterceptor.class)) // 指定攔截器                .make()                .load(HelloWord.class.getClassLoader()) // 加載生成的類                .getLoaded();
        // 創(chuàng)建動(dòng)態(tài)生成類的實(shí)例，并調(diào)用方法        HelloWord dynamicService = (HelloWord) dynamicType.newInstance();        dynamicService.printHelloWord();

public class LoggingInterceptor {    @RuntimeType    public static Object intercept(@AllArguments Object[] allArguments, @Origin Method method, @SuperCall Callable<?> callable) throws Exception {        // 打印start        System.out.println("start");        try {            // 調(diào)用原方法            Object result = callable.call();            // 打印end            System.out.println("end");            return result;        } catch (Exception e) {            System.out.println("exception end");            throw e;        }    }}

 // Parse the defined Interceptor class and related annotations        DefaultInterceptorClassParser interceptorClassParser = new DefaultInterceptorClassParser();        List<InterceptorProcessor> processors = interceptorClassParser.parse(HelloWorldInterceptor.class);        // load bytecode        ClassNode classNode = AsmUtils.loadClass(HelloWord.class);        // Enhanced process of loaded bytecodes        for (MethodNode methodNode : classNode.methods) {            MethodProcessor methodProcessor = new MethodProcessor(classNode, methodNode);            for (InterceptorProcessor interceptor : processors) {                interceptor.process(methodProcessor);            }        }

public class HelloWorldInterceptor {    @AtEnter(inline = true)    public static void atEnter() {        System.out.println("start");    }
    @AtExit(inline = true)    public static void atEit() {        System.out.println("end");    }}

<archive>   <manifestEntries>       // 指定premain()的所在方法       <Agent-CLass>com.ggc.agent.GhlAgent</Agent-CLass>       <Premain-Class>com.ggc.agent.GhlAgent</Premain-Class>       <Can-Redefine-Classes>true</Can-Redefine-Classes>       <Can-Retransform-Classes>true</Can-Retransform-Classes>   </manifestEntries></archive>               

public class GhlAgent {    public static Logger log = LoggerFactory.getLogger(GhlAgent.class);
    public static void agentmain(String agentArgs, Instrumentation instrumentation) {        log.info("agentmain方法");        boot(instrumentation);    }    public static void premain(String agentArgs, Instrumentation instrumentation) {        log.info("premain方法");        boot(instrumentation);    }    private static void boot(Instrumentation instrumentation) {        //創(chuàng)建一個(gè)代理增強(qiáng)對(duì)象        new AgentBuilder.Default().type(ElementMatchers.nameStartsWith("com.jd.aviation.performance.service.impl"))//攔截指定的類                .transform((builder, typeDescription, classLoader, javaModule) ->                        builder.method(ElementMatchers.isMethod().and(ElementMatchers.isPublic())                                ).intercept(MethodDelegation.to(TimingInterceptor.class))                ).installOn(instrumentation);    }}

public class TimingInterceptor {    public static Logger log = LoggerFactory.getLogger(TimingInterceptor.class);    @RuntimeType    public static Object intercept(@SuperCall Callable<?> callable) throws Exception {        long start = System.currentTimeMillis();        try {            // 原方法調(diào)用            return callable.call();        } finally {            long end = System.currentTimeMillis();            log.info("Method call took {} ms",(end - start));        }    }}

 protected boolean doInitialize(ProfilerContext profilerContext) {     AgentEnvService agentEnvService = (AgentEnvService)profilerContext.getService(AgentEnvService.class);     Instrumentation instrumentation = agentEnvService.instrumentation();     if (instrumentation == null) {       LOGGER.info("Instrumentation missing, PFinder PluginRegistrar enhance ignored!");       return false;     }     this.pluginLoaders = profilerContext.getAllService(PluginLoader.class);     this.enhanceHandler = new EnhancePluginHandler(profilerContext);     ElementMatcher.Junction<TypeDescription> typeMatcherChain = null;     for (PluginLoader pluginLoader : this.pluginLoaders) {       pluginLoader.loadPlugins(profilerContext);
       for (ElementMatcher.Junction<TypeDescription> typeMatcher : (Iterable<ElementMatcher.Junction<TypeDescription>>)pluginLoader.typeMatchers()) {         if (typeMatcherChain == null) {           typeMatcherChain = typeMatcher; continue;         }         typeMatcherChain = typeMatcherChain.or((ElementMatcher)typeMatcher);       }     }     if (typeMatcherChain == null) {       LOGGER.warn("no any enhance-point. pfinder enhance will be ignore.");       return false;     }     ConfigurationService configurationService = (ConfigurationService)profilerContext.getService(ConfigurationService.class);     String enhanceExcludePolicy = (String)configurationService.get(ConfigKey.PLUGIN_ENHANCE_EXCLUDE);
     LoadedClassSummaryHandler loadedClassSummaryHandler = null;     if (((Boolean)configurationService.get(ConfigKey.LOADED_CLASSES_SUMMARY_ENABLED, Boolean.valueOf(false))).booleanValue()) {       loadedClassSummaryHandler = new LoadedClassSummaryHandler.DefaultImpl(configurationService, ((ScheduledService)profilerContext.getService(ScheduledService.class)).getDefault());     }
     (new AgentBuilder.Default())
       .with(AgentBuilder.RedefinitionStrategy.RETRANSFORMATION)       .with(AgentBuilder.RedefinitionStrategy.REDEFINITION)       .with(new AgentBuilder.RedefinitionStrategy.Listener()         {           public void onBatch(int index, List<Class<?>> batch, List<Class<?>> types) {}           public Iterable<? extends List<Class<?>>> onError(int index, List<Class<?>> batch, Throwable throwable, List<Class<?>> types) {             return Collections.emptyList();           }           public void onComplete(int amount, List<Class<?>> types, Map<List<Class<?>>, Throwable> failures) {             for (Map.Entry<List<Class<?>>, Throwable> entry : failures.entrySet()) {               for (Class<?> aClass : entry.getKey()) {                 PluginRegistrar.LOGGER.warn("Redefine class: {} failure! ignored!", new Object[] { aClass.getName(), entry.getValue() });               }
             }           }         }).ignore((ElementMatcher)ElementMatchers.nameStartsWith("org.groovy.")         .or((ElementMatcher)ElementMatchers.nameStartsWith("jdk.nashorn."))         .or((ElementMatcher)ElementMatchers.nameStartsWith("javax.script."))         .or((ElementMatcher)ElementMatchers.nameContains("javassist"))         .or((ElementMatcher)ElementMatchers.nameContains(".asm."))         .or((ElementMatcher)ElementMatchers.nameContains("$EnhancerBySpringCGLIB$"))         .or((ElementMatcher)ElementMatchers.nameStartsWith("sun.reflect"))         .or((ElementMatcher)ElementMatchers.nameStartsWith("org.apache.jasper"))         .or((ElementMatcher)pfinderIgnoreMather())         .or((ElementMatcher)Matchers.forPatternLine(enhanceExcludePolicy))         .or((ElementMatcher)ElementMatchers.isSynthetic()))
       .type((ElementMatcher)typeMatcherChain)       .transform(this)       .with(new Listener(loadedClassSummaryHandler))       .installOn(instrumentation);     return true;   }

 public class TracingRunnable   implements PfinderWrappedRunnable {   private final Runnable origin;   private final TracingSnapshot<?> snapshot;   private final Component component;   private final String operationName;   private final String interceptorName;   private final InterceptorClassLoader interceptorClassLoader;
   public TracingRunnable(Runnable origin, TracingSnapshot<?> snapshot, Component component, String operationName, String interceptorName, InterceptorClassLoader interceptorClassLoader) {     this.origin = origin;     this.snapshot = snapshot;     this.component = component;     this.operationName = operationName;     this.interceptorClassLoader = interceptorClassLoader;     this.interceptorName = interceptorName;   }   public void run() {     TracingContext tracingContext = ContextManager.tracingContext();     if (tracingContext.isTracing() && tracingContext.traceId().equals(this.snapshot.getTraceId())) {       this.origin.run();       return;     }     LowLevelAroundTracingContext context = SpringAsyncTracingContext.create(this.operationName, this.interceptorName, this.snapshot, this.interceptorClassLoader, this.component);     context.onMethodEnter();     try {       this.origin.run();     } catch (RuntimeException ex) {       context.onException(ex);       throw ex;     } finally {       context.onMethodExit();     }   }   public Runnable getOrigin() {     return this.origin;   }   public String toString() {     return "TracingRunnable{origin=" + this.origin + ", snapshot=" + this.snapshot + ", component=" + this.component + ", operationName='" + this.operationName + '\'' + '}';   } }