Я пытаюсь изменить класс, который уже загружен в jvm. Решение, которое я нашел, это:
- 1. Прикрепите агента к jvm, указанному pid. (например, 8191) (коды: AttachTest).
- 2nd Найдите класс, который вы хотите изменить, из тех, которые уже были загружены в jvm (например, 8191).
- 3rd Добавить трансформатор с помощью инструмента (коды: AgentMain)
- 4th Изменить класс (например, Person) в
transform
методе (коды: DemoTransformer) - 5th Retransform класс, используя retransformClasses
Он отлично работает с 1-го шага до 5-го шага, но есть проблемы при retransformClasses
. Он снова вызвал transform
, который содержит коды для изменения класса. И Он модифицирует другие классы, которые я никогда не хочу изменять.
Я думаю, что проблема может возникнуть во время addTransformer
или retransformClasses
. Но я все еще смущен. Ну, как ретранслировать класс? Есть идеи? ТНХ
public class AttachTest {
public static void main(String[] args) throws AttachNotSupportedException,
IOException, AgentLoadException, AgentInitializationException {
String agentPath = "D:\\work\\workspace\\myjar\\loaded.jar";
String vid = args[0];
VirtualMachine vm = VirtualMachine.attach(vid);
vm.loadAgent(agentPath);
}
}
//Агент
public class AgentMain {
public static void agentmain (String agentArgs, Instrumentation inst)
throws ClassNotFoundException, UnmodifiableClassException,
InterruptedException {
Class<?> [] allLoadedClasses = inst.getAllLoadedClasses();
String tmpString = null;
for (int i = 0; i<allLoadedClasses.length; i++) {
tmpString = allLoadedClasses[i].getName();
if (0 != tmpString.length()) {
if (-1 != tmpString.lastIndexOf(".")) {
tmpString = tmpString.substring(tmpString.lastIndexOf(".")+1,tmpString.length());
}
if (tmpString.equals("Person")) {
inst.addTransformer(new DemoTransformer(), true);
inst.retransformClasses(allLoadedClasses[i]);
}
}
}
}
}
|
public class DemoTransformer implements ClassFileTransformer {
@Override
public byte[] transform (ClassLoader loader, String className,
Class<?> classBeingRedefined, ProtectionDomain protectionDomain,
byte[] classfileBuffer) throws IllegalClassFormatException {
ModifyMethodTest tm = new ModifyMethodTest(classfileBuffer);
byte[] byteArray = null;
try {
byteArray = tm.modiySleepMethod();
} catch (Exception e) {
e.printStackTrace();
}
return byteArray;
}
}
ВЫХОДЫ: ПРОГРАММА ATTACH
javax.management.RuntimeMBeanException: java.lang.RuntimeException: Failed to transform [Person]
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.rethrow(DefaultMBeanServerInterceptor.java:856)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.rethrowMaybeMBeanException(DefaultMBeanServerInterceptor.java:869)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:838)
at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:761)
at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1427)
at javax.management.remote.rmi.RMIConnectionImpl.access$200(RMIConnectionImpl.java:72)
at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1265)
at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1360)
at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:788)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:305)
at sun.rmi.transport.Transport$1.run(Transport.java:159)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:535)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:255)
at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:233)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:142)
at com.sun.jmx.remote.internal.PRef.invoke(Unknown Source)
at javax.management.remote.rmi.RMIConnectionImpl_Stub.invoke(Unknown Source)
at javax.management.remote.rmi.RMIConnector$RemoteMBeanServerConnection.invoke(RMIConnector.java:993)
at AttachStackOverflow.main(AttachStackOverflow.java:57)
Caused by: java.lang.RuntimeException: Failed to transform [Person]
at loaded3.TransformerService.transform(TransformerService.java:75)
at loaded3.TransformerService.transformClass(TransformerService.java:38)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:93)
at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:27)
at com.sun.jmx.mbeanserver.MBeanIntrospector.invokeM(MBeanIntrospector.java:208)
at com.sun.jmx.mbeanserver.PerInterface.invoke(PerInterface.java:120)
at com.sun.jmx.mbeanserver.MBeanSupport.invoke(MBeanSupport.java:262)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:836)
at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:761)
at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1427)
at javax.management.remote.rmi.RMIConnectionImpl.access$200(RMIConnectionImpl.java:72)
at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1265)
at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1360)
at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:788)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:305)
at sun.rmi.transport.Transport$1.run(Transport.java:159)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:535)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.UnsupportedOperationException: class redefinition failed: attempted to change the schema (add/remove fields)
at sun.instrument.InstrumentationImpl.retransformClasses0(Native Method)
at sun.instrument.InstrumentationImpl.retransformClasses(InstrumentationImpl.java:124)
at loaded3.TransformerService.transform(TransformerService.java:72)
... 31 more
ВЫХОДЫ: ЦЕЛЕВАЯ ПРОГРАММА
print Call sayHello()
print Hello World!
Supported Redefine
Supported Retransform
Call transform() in TransformerService
Add transformer
support redefine. return TRUE
support retransforme. return TRUE
IsModifiable class "class Person". return TRUE
Retransform classes
Number of times to Call transform() in DemoTransformer:1
####ASM CODE####
consturct ModifyMethodTest
Call modifySleepMethod
new classreader
new classwriter
construct ModifyClassAdapter
sayHello
consturct Modifymethod
[arg1] = java/io/PrintStream [arg2] = println #5
[arg1] = java/io/PrintStream [arg2] = println #13
[arg1] = java/util/concurrent/TimeUnit [arg2] = sleep #22
[arg1] = java/io/PrintStream [arg2] = println #30
sayHello2
consturct Modifymethod
[arg1] = java/io/PrintStream [arg2] = println #5
[arg1] = java/io/PrintStream [arg2] = println #13
<init>
consturct Modifymethod
[arg1] = java/lang/Object [arg2] = <init> #1
main
consturct Modifymethod
[arg1] = Person [arg2] = <init> #4
[arg1] = Person [arg2] = sayHello #9
[arg1] = Person [arg2] = sayHello2 #13
[arg1] = java/lang/InterruptedException [arg2] = printStackTrace #21
getName
consturct Modifymethod
setName
consturct Modifymethod
Call visitend
Finished to call modifymethodtest
####End of ASM CODE
Remove transformer
Call transform() in TransformerService
Add transformer
support redefine. return TRUE
support retransforme. return TRUE
IsModifiable class "class Person". return TRUE
Retransform classes
Number of times to Call transform() in DemoTransformer:2
####ASM CODE####
consturct ModifyMethodTest
Call modifySleepMethod
new classreader
new classwriter
construct ModifyClassAdapter
sayHello
consturct Modifymethod
[arg1] = java/io/PrintStream [arg2] = println #5
[arg1] = java/io/PrintStream [arg2] = println #13
[arg1] = java/util/concurrent/TimeUnit [arg2] = sleep #22
[arg1] = java/io/PrintStream [arg2] = println #30
sayHello2
consturct Modifymethod
[arg1] = java/io/PrintStream [arg2] = println #5
[arg1] = java/io/PrintStream [arg2] = println #13
<init>
consturct Modifymethod
[arg1] = java/lang/Object [arg2] = <init> #1
main
consturct Modifymethod
[arg1] = Person [arg2] = <init> #4
[arg1] = Person [arg2] = sayHello #9
[arg1] = Person [arg2] = sayHello2 #13
[arg1] = java/lang/InterruptedException [arg2] = printStackTrace #21
getName
consturct Modifymethod
setName
consturct Modifymethod
Call visitend
Finished to call modifymethodtest
####End of ASM CODE
Remove transformer
print in sayHello()
print Call sayHello2()
print Hello World!2