The original method, using agentmain when using Javassist tool handle copy out a new method to handle, and then modify the original method called handle $old, and then set up replication handle method of method body, run times out the mistakes in the title, with bosses know what use agentmain is not new methods such as limit?

 
CtMethod CtMethod=ctClass. GetDeclaredMethod (methodName);//get this method instance 
//create a new method, for the original copy of the original method, the name name 
CtMethod newMethod=CtNewMethod. Copy (CtMethod, methodName, ctClass, null); 
//define a method name used to describe the modified bytecode before the original method of 
String oldMethodName=methodName + "$old"; 
//amend the name of the original method, avoid conflict and the newly added method name 
CtMethod. Elegantly-named setName (oldMethodName); 

//build new method body 
The StringBuilder bodyStr=new StringBuilder (); 
BodyStr. Append (" {"); 
BodyStr. Append (" long startTime=System. CurrentTimeMillis (); \n"); 
//call the method code, similar to the method (); All the parameters ($$) said 
BodyStr. Append (oldMethodName). Append (" ($$); \n"); 
BodyStr. Append (" long endTime=System. CurrentTimeMillis (); \n"); 
String outputStr="System. Out. Println (" this method "+ methodName 
+ cost: \ "" + (endTime - startTime) + " Ms. \ "); \n"; 
BodyStr. Append (outputStr); 
BodyStr. Append ("} "); 

//set the new target method method body 
NewMethod. SetBody (bodyStr. ToString ()); 
//add new method, name of the original method has been modified for oldMethodName, call will call to the new target method 
CtClass. AddMethod (newMethod); 

CodePudding user response:

wan chun on the ground floor

CodePudding user response:

Adding a field or method is impossible as it is today, only the code evolution VM supports it as of today and it is doubtful if this feature (top service it to its.

CodePudding user response:

With the an AgentBuilder, you should register a Listener to see if the errors happen during retransformation. You probably should set the disableClassFormatChanges () as the business, the JVM does not support adding the methods or fields to a class that already is defined.

CodePudding user response:

reference NANU NANA - reply: 3/f

With an AgentBuilder, you should register a Listener to see if the errors happen during retransformation. You probably should set the disableClassFormatChanges () as the business, the JVM does not support adding the methods or fields to a class that already is defined.

Wow,, I am looking for a document not found, nana to help give a url, thanks