基于javaagent-ByteBuddy监控方法执行耗时

前言

• 目的：不改造原有项目代码，通过字节码增强技术来实现方法调用耗时
• 学习：最近学习Skywalking时偶然接触到有关字节码方面的知识，特地记录一下（还可以通过javassist来实现）
• 参考资料：
  【黑马Skywalking】： java基础教程深入学习Skywalking全套教程

目录结构

环境准备

1. java-agent-demo项目pom：

    <properties>
        <maven.compiler.source>8maven.compiler.source>
        <maven.compiler.target>8maven.compiler.target>
    properties>

    <dependencies>
        
        <dependency>
            <groupId>net.bytebuddygroupId>
            <artifactId>byte-buddyartifactId>
            <version>1.9.2version>
        dependency>
        <dependency>
            <groupId>net.bytebuddygroupId>
            <artifactId>byte-buddy-agentartifactId>
            <version>1.9.2version>
        dependency>
    dependencies>


    <build>
        <plugins>
            <plugin>
                <artifactId>maven-assembly-pluginartifactId>
                <configuration>
                    <appendAssemblyId>falseappendAssemblyId>
                    <descriptorRefs>
                        
                        <descriptorRef>jar-with-dependenciesdescriptorRef>
                    descriptorRefs>
                    <archive>
                        
                        <manifestEntries>
                            <Premain-Class>PreMainAgentPremain-Class>
                            <Agent-Class>PreMainAgentAgent-Class>
                            <Can-Redefine-Classes>trueCan-Redefine-Classes>
                            <Can-Retransform-Classes>trueCan-Retransform-Classes>
                        manifestEntries>
                    archive>
                configuration>
                <executions>
                    <execution>
                        <id>make-assemblyid>
                        <phase>packagephase>
                        <goals>
                            <goal>singlegoal>
                        goals>
                    execution>
                executions>
            plugin>
        plugins>
    build>

2. PreMainAgentl类：
注意：测试项目要以com.agent前缀开头才能被统计

import net.bytebuddy.agent.builder.AgentBuilder;
import net.bytebuddy.description.method.MethodDescription;
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 PreMainAgent {

    public static void premain(String agentParam, Instrumentation inst) {
        System.out.println("premain已经执行1" + agentParam);
        // method指定哪些方法需要被拦截，ElementMathers.any指定了所有的方法，声明intercept拦截器
        AgentBuilder.Transformer transformer = new AgentBuilder.Transformer() {
            @Override
            public DynamicType.Builder<?> transform(DynamicType.Builder<?> builder, 
                                                    TypeDescription typeDescription, 
                                                    ClassLoader classLoader, 
                                                    JavaModule javaModule) {
                return builder.method(ElementMatchers.<MethodDescription>any())
                        .intercept(MethodDelegation.to(MyIntercept.class));
            }
        };
        /**
         * 1.type指定了agent拦截的包名，以[com.agent]作为前缀
         * 2.指定了转换器transformer
         * 3.将配置安装到Instrumentation
         */
        new AgentBuilder.Default()
                .type(ElementMatchers.<TypeDescription>nameStartsWith("com.agent"))
                .transform(transformer)
                .installOn(inst);
    }

    public static void premain(String agentParam) {
        System.out.println("premain已经执行2" + agentParam);
    }
}

3. MyIntercept类：

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 MyIntercept  {

    @RuntimeType
    public static Object intercept(@Origin Method method,
                                   @SuperCall Callable<?> callable) throws Exception {
        long start = System.currentTimeMillis();
        try {
            return callable.call();
        } finally {
            System.out.println(method + ":" + (System.currentTimeMillis() - start) + "ms");
        }
    }
}

4. Main类：
注意：测试项目要以com.agent前缀开头才能被统计

public class Main {
    public static void main(String[] args) throws InterruptedException {
        System.out.println("main方法执行");
        Thread.sleep(1000);
    }
}

测试结果

1. java-agent-demo打jar包
注意：记住java-agent-demo的jar包路径

2. 测试项目启动参数
在测试项目中的启动VM options添加一下参数，我自己随便用的参数：guantest

-javaagent:D:\project4\java-agent-demo\target\java-agent-demo-1.0-SNAPSHOT.jar=guantest

3. 测试结果