目标： 输出各函数执行时间
- 引包
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>org.example</groupId><artifactId>bytebuddyTest</artifactId><version>1.0-SNAPSHOT</version><properties></properties><dependencies><dependency><groupId>net.bytebuddy</groupId><artifactId>byte-buddy</artifactId><version>1.8.20</version></dependency><dependency><groupId>net.bytebuddy</groupId><artifactId>byte-buddy-agent</artifactId><version>1.8.20</version></dependency></dependencies><build><plugins><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><configuration><source>8</source><target>8</target></configuration></plugin><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-jar-plugin</artifactId><configuration><archive>// maven中指定Premain-Class<manifestEntries><Premain-Class>buddy.agent.MethodAgent</Premain-Class><Can-Redefine-Classes>true</Can-Redefine-Classes><Can-Retransform-Classes>true</Can-Retransform-Classes></manifestEntries></archive></configuration></plugin></plugins></build></project>
- Pre-Main 操作类
package buddy.agent;import net.bytebuddy.agent.builder.AgentBuilder;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.dynamic.DynamicType;
import net.bytebuddy.implementation.MethodDelegation;
import net.bytebuddy.matcher.ElementMatchers;
import net.bytebuddy.utility.JavaModule;import java.lang.instrument.Instrumentation;public class MethodAgent {public static void premain(String args, Instrumentation instrumentation) {System.err.println("MethodAgent " + args);AgentBuilder.Transformer transformer = (builder, typeDescription, classLoader, javaModule) -> {return builder.method(ElementMatchers.any()).intercept(MethodDelegation.to(MethodTimeCheck.class));};AgentBuilder.Listener listener = new AgentBuilder.Listener() {@Overridepublic void onDiscovery(String s, ClassLoader classLoader, JavaModule javaModule, boolean b) {System.out.println(s + " onDiscovery");}@Overridepublic void onTransformation(TypeDescription typeDescription, ClassLoader classLoader, JavaModule javaModule, boolean b, DynamicType dynamicType) {System.out.println(typeDescription + " onTransformation");}@Overridepublic void onIgnored(TypeDescription typeDescription, ClassLoader classLoader, JavaModule javaModule, boolean b) {System.out.println(typeDescription + " onIgnored");}@Overridepublic void onError(String s, ClassLoader classLoader, JavaModule javaModule, boolean b, Throwable throwable) {throwable.printStackTrace();}@Overridepublic void onComplete(String s, ClassLoader classLoader, JavaModule javaModule, boolean b) {System.out.println(s + " onComplete");}};new AgentBuilder.Default().type(ElementMatchers.nameStartsWith("buddy.say")).transform(transformer).with(listener).installOn(instrumentation);}
}拦截器处理类
package buddy.agent;import net.bytebuddy.implementation.bind.annotation.Origin;
import net.bytebuddy.implementation.bind.annotation.RuntimeType;
import net.bytebuddy.implementation.bind.annotation.SuperCall;import java.lang.reflect.Method;
import java.util.concurrent.Callable;public class MethodTimeCheck {@RuntimeTypepublic static void interceptor(@Origin Method method, @SuperCall Callable<?> callable) {long startTime =System.currentTimeMillis();try {callable.call();} catch (Exception e) {e.printStackTrace();} finally {System.out.println(method + " cost " + (System.currentTimeMillis() - startTime) + " ms");}}}- maven 打包，然后在VM option 中添加 -javaagent:XXX(your path).jar=args
- 测试类
package buddy.say;public class HelloMethod {public void say() {try {Thread.sleep(1000);System.out.println("execute OK~");} catch (Exception e) {e.printStackTrace();}}
}package buddy;import buddy.say.HelloMethod;public class StartExecute {public static void main(String[] args) {HelloMethod helloMethod = new HelloMethod();helloMethod.say();}
}
结束 ~ ~ （^ v ^）~ ~
