将参数传递给 bytebuddy 拦截器

Question

我有一个使用 Byte Buddy 的拦截器，我想向拦截器传递一个参数。我该怎么做？

ExpressionHandler expressionHandler = ... // a handler 
Method method = ... // the method that will be intercepted
ByteBuddy bb = new ByteBuddy();
bb.subclass(theClazz)
   .method(ElementMatchers.is(method))
   .intercept(MethodDelegation.to(MethodInterceptor.class));
   .make()
   .load(theClazz.getClassLoader(), ClassLoadingStrategy.Default.WRAPPER);

MethodInterceptor中的拦截方法是：

@RuntimeType
public static Attribute intercept(@Origin Method method, @AllArguments Object[] args) throws Exception {       
    String name = method.getName();
    Class<? extends Attribute> type = (Class<? extends Attribute>) method.getReturnType();
    ExpressionHandler expressionHandler= // ??? 
    expressionHandler.attachStuff(name, type);
    return expressionHandler;
}

如何将 expressionHandler 从构建器传递到拦截器方法？

Answer 1

简单地使用实例委托而不是class级委托：

MethodDelegation.to(new MethodInterceptor(expressionHandler))

和

public class MethodInterceptor {

  private final ExpressionHandler expressionHandler;

  public MethodInterceptor(ExpressionHandler expressionHandler) {
    this.expressionHandler = expressionHandler;
  }

  @RuntimeType
  public Attribute intercept(@Origin Method method, @AllArguments Object[] args) throws Exception {       
    String name = method.getName();
    Class<? extends Attribute> type = (Class<? extends Attribute>) method.getReturnType();
    this.expressionHandler.attachStuff(name, type);
    return expressionHandler;
  }
}

将参数传递给 bytebuddy 拦截器

Pass argument to bytebuddy interceptor

java

instrumentation

bytecode

byte-buddy