Spring Shell和使用Attach API
2022-01-21 本文已影响0人
东南枝下
Spring Shell简单使用
spring-shell中已经包含了spring-boot-starter，直接依赖就可以使用
- 引入依赖
<dependency>
<groupId>org.springframework.shell</groupId>
<artifactId>spring-shell-starter</artifactId>
<version>2.0.0.RELEASE</version>
</dependency>
- 启动类
/**
* @author Jenson
*/
@SpringBootApplication
public class SpringShellApplication {
public static void main(String[] args) {
SpringApplication.run(SpringShellApplication.class, args);
}
}
- 直接启动就可以使用
使用help命令可以看到，有一些基础命令
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.0.4.RELEASE)
2022-01-21 17:37:10.184 INFO 73896 --- [ main] com.jenson.SpringShellApplication : Starting SpringShellApplication on localhost with PID 73896 (started by Jenson in /Users/gy/MyCode/write-own-code-to-paly/java代码/hotchpotch)
2022-01-21 17:37:10.190 INFO 73896 --- [ main] com.jenson.SpringShellApplication : No active profile set, falling back to default profiles: default
2022-01-21 17:37:10.315 INFO 73896 --- [ main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@77e4c80f: startup date [Fri Jan 21 17:37:10 CST 2022]; root of context hierarchy
2022-01-21 17:37:12.617 WARN 73896 --- [ main] org.jline : Unable to create a system terminal, creating a dumb terminal (enable debug logging for more information)
2022-01-21 17:37:12.957 INFO 73896 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2022-01-21 17:37:12.991 INFO 73896 --- [ main] com.jenson.SpringShellApplication : Started SpringShellApplication in 3.561 seconds (JVM running for 4.363)
shell:>
shell:>
shell:>
shell:>help
AVAILABLE COMMANDS
Built-In Commands
clear: Clear the shell screen.
exit, quit: Exit the shell.
help: Display help about available commands.
script: Read and execute commands from a file.
stacktrace: Display the full stacktrace of the last error.
- 创建命令
创建一个查询java进程和使用attach-api把agent的jar包添加到指定进程号到Java程序中的命令
package com.jenson.command;
import com.sun.tools.attach.VirtualMachine;
import com.sun.tools.attach.VirtualMachineDescriptor;
import org.springframework.shell.standard.ShellComponent;
import org.springframework.shell.standard.ShellMethod;
import java.io.IOException;
import java.util.List;
/**
* @author Jenson
*/
@ShellComponent
public class VmCommand {
@ShellMethod(value = "查询所有java进程号")
public void pid() {
List<VirtualMachineDescriptor> vmList = VirtualMachine.list();
vmList.forEach(vm->{
System.out.println(vm.id() + " " +vm.displayName());
});
}
@ShellMethod(key = {"attach-jar"},value = "把jar包通过attach-api加进去")
public void attachJar(String pid,String path){
VirtualMachine vm = null;
try {
//进程ID
vm = VirtualMachine.attach(pid);
//java agent jar包路径
vm.loadAgent(path);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (vm != null) {
try {
vm.detach();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
- 使用该命令
shell:>pid
58854 org.jetbrains.idea.maven.server.RemoteMavenServer36
1352
73896 com.jenson.SpringShellApplication
74140 org.jetbrains.jps.cmdline.Launcher /Applications/...
73692 org.jetbrains.idea.maven.server.RemoteMavenServer36
74143 com.jenson.Application
74142 org.jetbrains.jps.cmdline.Launcher /Applications/...
shell:>
shell:>
shell:>attach-jar --pid 74143 --path ~/hotchpotch/attach-agent/target/attach-agent.jar
上述使用attach-agent.jar来修改进程号为74143的java程序的代码
agent.jar编写，动态修改字节码
- 引入依赖
使用ASM来修改字节码
<dependency>
<groupId>org.ow2.asm</groupId>
<artifactId>asm</artifactId>
<version>7.1</version>
</dependency>
<dependency>
<artifactId>asm-commons</artifactId>
<groupId>org.ow2.asm</groupId>
<version>7.1</version>
</dependency>
- 增加打包插件
<build>
<finalName>attach-agent</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.2.0</version>
<configuration>
<archive>
<!-- 打jar的文件清单，对应META-INF/MANIFEST.MF文件 -->
<manifestEntries>
<!-- 主程序启动类 -->
<Agent-Class>
com.jenson.AgentMain
</Agent-Class>
<!-- 允许重新定义类 -->
<Can-Redefine-Classes>true</Can-Redefine-Classes>
<!-- 允许转换并重新加载类 -->
<Can-Retransform-Classes>true</Can-Retransform-Classes>
</manifestEntries>
</archive>
</configuration>
</plugin>
</plugins>
</build>
- 创建函数的visitor，修改函数返回值
package com.jenson.visitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.commons.AdviceAdapter;
/**
* @author Jenson
*/
public class MyMethodVisitor extends AdviceAdapter {
protected MyMethodVisitor(int api, MethodVisitor methodVisitor, int access, String name, String descriptor) {
super(api, methodVisitor, access, name, descriptor);
}
@Override
protected void onMethodEnter() {
//从常量池加载字符串
mv.visitLdcInsn("------我是Agent-----");
//返回
mv.visitInsn(ARETURN);
}
}
- 创建类的visitor，查找指定函数，调用上述方法修改函数返回值
package com.jenson.visitor;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.MethodVisitor;
/**
* @author Jenson
*/
public class MyClassVisitor extends ClassVisitor {
public MyClassVisitor(int api, ClassVisitor cv) {
super(api, cv);
}
@Override
public MethodVisitor visitMethod(int access, String name, String descriptor, String signature,
String[] exceptions) {
MethodVisitor mv = super.visitMethod(access, name, descriptor, signature, exceptions);
if ("chickList".equals(name)) {
System.out.println("----准备修改chickList方法----");
return new MyMethodVisitor(api,mv,access,name,descriptor);
}
return mv;
}
}
- 定义类转化器，修改指定类的字节码
package com.jenson.transformer;
import com.jenson.visitor.MyClassVisitor;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Opcodes;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.security.ProtectionDomain;
/**
* 自定义类文件转换器，通过ASM修改类字节码
* @author Jenson
*/
public class MyClassFileTransformer implements ClassFileTransformer {
@Override
public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {
String finalClassName = className.replace("/", ".");
System.out.println("----是不是没有执行下面: "+finalClassName);
if ("com.jenson.controller.v1.ChickController".equals(finalClassName)) {
System.out.println("----是不是没有执行这里1-----");
//以下为ASM常规操作，详情可以查看ASM使用相关文档
ClassReader cr = new ClassReader(classfileBuffer);
ClassWriter cw = new ClassWriter(cr,ClassWriter.COMPUTE_FRAMES);
ClassVisitor cv = new MyClassVisitor(Opcodes.ASM7,cw);
cr.accept(cv,ClassReader.SKIP_FRAMES | ClassReader.SKIP_DEBUG);
return cw.toByteArray();
}
return null;
}
}
- 编写Agent-Class
package com.jenson;
import com.jenson.transformer.MyClassFileTransformer;
import java.lang.instrument.Instrumentation;
import java.lang.instrument.UnmodifiableClassException;
/**
* @author Jenson
*/
public class AgentMain {
public static void agentmain(String agentArgs, Instrumentation inst) throws UnmodifiableClassException {
System.out.println("---agent called---");
//添加类文件转换器，第二个参数必须设置为true，表示可以重新转换类文件
inst.addTransformer(new MyClassFileTransformer(),true);
Class[] classes = inst.getAllLoadedClasses();
for (int i = 0; i < classes.length; i++) {
if ("com.jenson.controller.v1.ChickController".equals(classes[i].getName())) {
System.out.println("----重新加载ChickController开始----");
inst.retransformClasses(classes[i]);
System.out.println("----重新加载ChickController完毕----");
break;
}
}
}
}
- 打包
mvn clean package
- 被修改字节码的Java程序需要引入依赖
<dependency>
<groupId>org.ow2.asm</groupId>
<artifactId>asm</artifactId>
<version>7.1</version>
</dependency>
<dependency>
<artifactId>asm-commons</artifactId>
<groupId>org.ow2.asm</groupId>
<version>7.1</version>
</dependency>
如果没加这个依赖就会报错
spring shell 的attach报错
shell:>attach-jar --pid 74855 --path ～/hotchpotch/attach-agent/target/attach-agent.jar
shell:>com.sun.tools.attach.AgentInitializationException: Agent JAR loaded but agent failed to initialize
at sun.tools.attach.HotSpotVirtualMachine.loadAgent(HotSpotVirtualMachine.java:121)
at com.sun.tools.attach.VirtualMachine.loadAgent(VirtualMachine.java:540)
at com.jenson.command.VmCommand.attachJar(VmCommand.java:32)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:223)
at org.springframework.shell.Shell.evaluate(Shell.java:169)
at org.springframework.shell.Shell.run(Shell.java:134)
at org.springframework.shell.jline.InteractiveShellApplicationRunner.run(InteractiveShellApplicationRunner.java:84)
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:791)
at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:781)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:338)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1258)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246)
at com.jenson.SpringShellApplication.main(SpringShellApplication.java:18)
被attach的java程序报错
Exception in thread "Attach Listener" java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:386)
at sun.instrument.InstrumentationImpl.loadClassAndCallAgentmain(InstrumentationImpl.java:411)
Caused by: java.lang.NoClassDefFoundError: org/objectweb/asm/ClassVisitor
at com.jenson.AgentMain.agentmain(AgentMain.java:15)
... 6 more
Caused by: java.lang.ClassNotFoundException: org.objectweb.asm.ClassVisitor
at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 7 more
Agent failed to start!
- 测试
attach 前调用接口
图片.png
attach后调用接口
图片.png
spring-shell参考:https://www.cnblogs.com/nuccch/p/11067342.html
attach-api参考:https://www.cnblogs.com/xuxiaojian/p/14537375.html
ASM官方入门手册:https://asm.ow2.io/asm4-guide.pdf
