【字节码】Java agent+ASM实战--监控所有方法执行时间

转x33g5p2x  于2022-06-20 转载在 Java  
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1.概述

在上一篇文章：【字节码】Java Instrumentation 简介 以及 ASM 组合案例 因为这篇文章我一直找不到原因，然后找到了这篇文章。

转载：JVM插码之五：Java agent+ASM实战–监控所有方法执行时间

本文建立在对instrumentation和agent有初步的了解的前提下阅读，关于这2个类的讲解在其它文章中。

这是一个maven项目，pom中需要的配置，lib中有asm的jar包

maven如下

  1. <groupId>org.example</groupId>
  2.     <artifactId>javaagent-apiv2</artifactId>
  3.     <version>1.0-SNAPSHOT</version>
  4.     <packaging>jar</packaging>
  6.     <properties>
  7.         <maven.compiler.source>8</maven.compiler.source>
  8.         <maven.compiler.target>8</maven.compiler.target>
  9.         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  10.         <asm.version>9.0</asm.version>
  11.     </properties>
  13.     <dependencies>
  14.         <dependency>
  15.             <groupId>org.ow2.asm</groupId>
  16.             <artifactId>asm-analysis</artifactId>
  17.             <version>${asm.version}</version>
  18.         </dependency>
  19.         <dependency>
  20.             <groupId>org.ow2.asm</groupId>
  21.             <artifactId>asm-commons</artifactId>
  22.             <version>${asm.version}</version>
  23.         </dependency>
  24.         <dependency>
  25.             <groupId>org.ow2.asm</groupId>
  26.             <artifactId>asm-tree</artifactId>
  27.             <version>${asm.version}</version>
  28.         </dependency>
  29.         <dependency>
  30.             <groupId>org.ow2.asm</groupId>
  31.             <artifactId>asm-util</artifactId>
  32.             <version>${asm.version}</version>
  33.         </dependency>
  34.         <dependency>
  35.             <groupId>javassist</groupId>
  36.             <artifactId>javassist</artifactId>
  37.             <version>3.12.1.GA</version>
  38.         </dependency>
  40.         <!-- https://mvnrepository.com/artifact/cglib/cglib -->
  41.         <dependency>
  42.             <groupId>cglib</groupId>
  43.             <artifactId>cglib</artifactId>
  44.             <version>3.2.5</version>
  45.         </dependency>
  47.         <!-- https://mvnrepository.com/artifact/oro/oro -->
  48.         <dependency>
  49.             <groupId>oro</groupId>
  50.             <artifactId>oro</artifactId>
  51.             <version>2.0.8</version>
  52.         </dependency>
  53.         <dependency>
  54.             <groupId>junit</groupId>
  55.             <artifactId>junit</artifactId>
  56.             <version>3.8.1</version>
  57.             <scope>test</scope>
  58.         </dependency>
  59.     </dependencies>
  60.     <build>
  61.         <plugins>
  62.             <plugin>
  63.                 <groupId>org.apache.maven.plugins</groupId>
  64.                 <artifactId>maven-compiler-plugin</artifactId>
  65.                 <configuration>
  66.                     <source>1.8</source>
  67.                     <target>1.8</target>
  68.                     <encoding>utf-8</encoding>
  69.                 </configuration>
  70.             </plugin>
  71.             <plugin>
  72.                 <groupId>org.apache.maven.plugins</groupId>
  73.                 <artifactId>maven-shade-plugin</artifactId>
  74.                 <version>3.0.0</version>
  75.                 <executions>
  76.                     <execution>
  77.                         <phase>package</phase>
  78.                         <goals>
  79.                             <goal>shade</goal>
  80.                         </goals>
  81.                         <configuration>
  82.                             <transformers>
  83.                                 <transformer
  84.                                         implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
  85.                                     <manifestEntries>
  86.                                         <!-- <Premain-Class>com.dxz.chama.javaagent.patter.TimeMonitorPatterAgent</Premain-Class> -->
  87.                                         <!-- <Premain-Class>com.dxz.chama.javaagent.StatAgent</Premain-Class> -->
  88.                                         <Premain-Class>com.javaagent.api.UdAgent</Premain-Class>
  89.                                     </manifestEntries>
  90.                                 </transformer>
  91.                             </transformers>
  92.                         </configuration>
  93.                     </execution>
  94.                 </executions>
  95.             </plugin>
  96.         </plugins>
  97.     </build>
  99. </project>

agent类，只有一个方法，就是把自定义的类修改器添加到instrumentation中。

  1. public class UdAgent {
  2.     public static void premain(String agentArgs, Instrumentation instrumentation){
  3.         instrumentation.addTransformer(new LogTransformer());
  4.     }
  5. }

类转换器实现：

  1. import java.io.IOException;
  2. import java.lang.instrument.ClassFileTransformer;
  3. import java.lang.instrument.IllegalClassFormatException;
  4. import java.security.ProtectionDomain;
  6. import org.objectweb.asm.ClassReader;
  7. import org.objectweb.asm.ClassWriter;
  9. public class LogTransformer implements ClassFileTransformer {
  10.     @Override
  11.     public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined,
  12.                             ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {
  13.         try {
  14.             ClassReader cr = new ClassReader(className);
  15.             ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
  16.             TimeCountAdpter timeCountAdpter = new TimeCountAdpter(cw);
  18.             cr.accept(timeCountAdpter, ClassReader.EXPAND_FRAMES);
  20.             return cw.toByteArray();
  21.         } catch (IOException e) {
  22.             e.printStackTrace();
  23.         }
  24.         return null;
  25.     }
  26. }

实际修改字节码的方法，这里给每个类添加了一个字段UDASMCN，用于记录当前类的名字（方便打印信息）。同时记录每个方法的名字，以及执行时间。

  1. import org.objectweb.asm.ClassVisitor;
  2. import org.objectweb.asm.FieldVisitor;
  3. import org.objectweb.asm.MethodVisitor;
  4. import org.objectweb.asm.Opcodes;
  5. import org.objectweb.asm.Type;
  6. import org.objectweb.asm.commons.AnalyzerAdapter;
  7. import org.objectweb.asm.commons.LocalVariablesSorter;
  9. public class TimeCountAdpter extends ClassVisitor implements Opcodes {
  10.     private String owner;
  11.     private boolean isInterface;
  12.     private String filedName = "UDASMCN";
  13.     private int acc = Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC + Opcodes.ACC_FINAL;
  14.     private boolean isPresent = false;
  16.     private String methodName;
  18.     public TimeCountAdpter(ClassVisitor classVisitor) {
  19.         super(ASM6, classVisitor);
  20.     }
  22.     @Override
  23.     public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
  24.         super.visit(version, access, name, signature, superName, interfaces);
  25.         owner = name;
  26.         isInterface = (access & ACC_INTERFACE) != 0;
  27.     }
  29.     @Override
  30.     public FieldVisitor visitField(int access, String name, String descriptor, String signature, Object value) {
  31.         if (name.equals(filedName)) {
  32.             isPresent = true;
  33.         }
  34.         return super.visitField(access, name, descriptor, signature, value);
  35.     }
  37.     @Override
  38.     public MethodVisitor visitMethod(int access, String name, String descriptor, String signature,
  39.                                      String[] exceptions) {
  40.         MethodVisitor mv = cv.visitMethod(access, name, descriptor, signature, exceptions);
  42.         if (!isInterface && mv != null && !name.equals("<init>") && !name.equals("<clinit>")) {
  43.             methodName = name;
  44.             AddTimerMethodAdapter at = new AddTimerMethodAdapter(mv);
  45.             at.aa = new AnalyzerAdapter(owner, access, name, descriptor, at);
  46.             at.lvs = new LocalVariablesSorter(access, descriptor, at.aa);
  48.             return at.lvs;
  49.         }
  51.         return mv;
  52.     }
  54.     public void visitEnd() {
  55.         if (!isInterface) {
  56.             FieldVisitor fv = cv.visitField(acc, filedName, "Ljava/lang/String;", null, owner);
  57.             if (fv != null) {
  58.                 fv.visitEnd();
  59.             }
  60.         }
  61.         cv.visitEnd();
  62.     }
  64.     class AddTimerMethodAdapter extends MethodVisitor {
  65.         private int time;
  66.         private int maxStack;
  67.         public LocalVariablesSorter lvs;
  68.         public AnalyzerAdapter aa;
  70.         public AddTimerMethodAdapter(MethodVisitor methodVisitor) {
  71.             super(ASM6, methodVisitor);
  72.         }
  74.         @Override
  75.         public void visitCode() {
  76.             mv.visitCode();
  77.             mv.visitMethodInsn(INVOKESTATIC, "java/lang/System", "nanoTime", "()J", false);
  78.             time = lvs.newLocal(Type.LONG_TYPE);
  79.             mv.visitVarInsn(LSTORE, time);
  80.             maxStack = 4;
  81.         }
  83.         @Override
  84.         public void visitInsn(int opcode) {
  85.             if (((opcode >= IRETURN && opcode <= RETURN) || opcode == ATHROW) && !isPresent) {
  86.                 mv.visitMethodInsn(INVOKESTATIC, "java/lang/System", "nanoTime", "()J", false);
  87.                 mv.visitVarInsn(LLOAD, time);
  88.                 mv.visitInsn(LSUB);
  89.                 mv.visitVarInsn(LSTORE, time);
  91.                 mv.visitFieldInsn(GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");
  93.                 mv.visitTypeInsn(NEW, "java/lang/StringBuilder");
  94.                 mv.visitInsn(DUP);
  95.                 mv.visitMethodInsn(INVOKESPECIAL, "java/lang/StringBuilder", "<init>", "()V", false);
  96.                 mv.visitFieldInsn(GETSTATIC, owner, filedName, "Ljava/lang/String;");
  97.                 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append",
  98.                         "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
  100.                 mv.visitLdcInsn("  " + methodName + ":");
  101.                 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append",
  102.                         "(Ljava/lang/String;)Ljava/lang/StringBuilder;", false);
  104.                 mv.visitVarInsn(LLOAD, time);
  105.                 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "append", "(J)Ljava/lang/StringBuilder;",
  106.                         false);
  107.                 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/StringBuilder", "toString", "()Ljava/lang/String;", false);
  108.                 mv.visitMethodInsn(INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V", false);
  110.                 maxStack = Math.max(aa.stack.size() + 4, maxStack);
  111.             }
  112.             mv.visitInsn(opcode);
  113.         }
  115.         @Override
  116.         public void visitMaxs(int maxStack, int maxLocals) {
  117.             super.visitMaxs(Math.max(maxStack, this.maxStack), maxLocals);
  118.         }
  119.     }
  121. }

打包成jar包后，在另一个程序启动时调用，启动参数如下：

  1. lcc@lcc javaagent-apiv2$ java -javaagent:./target/javaagent-apiv2-1.0-SNAPSHOT.jar 
  3. java/lang/Shutdown  runHooks:3294
  4. java/lang/Shutdown  sequence:43843
  5. java/lang/Shutdown  shutdown:56371

执行效果：

时间单位是纳秒，可以看到每个方法执行完时，都会打印这个方法 的执行时间，以com/Main main:11457636为例，说明类com/Main的main方法执行力11毫秒。

版权说明 : 本文为转载文章, 版权归原作者所有 版权申明

原文链接 : https://blog.csdn.net/qq_21383435/article/details/125305636

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