bytebuddy拦截方法中使用Methodcall有没有办法调用带字段的变长参数方法？

Question

我正在尝试 return 使用 bytebuddy 将某些字段作为列表。我使用 MethodCall 调用了 Arrays.asList()，但它无法处理可变长度参数。还有其他方法吗？

public class TestClass {
    int a;
    int b;
    
    public List<?> getFields(){
        throw new RuntimeException("Bytebuddy not work.");
    }
}

new ByteBuddy()
                .rebase(TypePool.Default.ofSystemLoader().describe("com.test.TestClass").resolve(), 
                        ClassFileLocator.ForClassLoader.ofSystemLoader())
                .method(ElementMatchers.named("getFields"))
                .intercept(MethodCall.invoke(Arrays.class.getMethod("asList", Object[].class))
                        .withField("a", "b"))       
                .make()
                .load(ClassLoader.getSystemClassLoader(), ClassLoadingStrategy.Default.INJECTION)
                .getLoaded();
        
        TestClass testTarget = new TestClass();
        LOG.info("result : {}", testTarget.getFields());

错误：

Exception in thread "main" java.lang.ExceptionInInitializerError Caused by: java.lang.IllegalStateException: public static java.util.List java.util.Arrays.asList(java.lang.Object[]) does not accept 2 arguments at net.bytebuddy.implementation.MethodCall$Appender.toStackManipulation(MethodCall.java:3537) at net.bytebuddy.implementation.MethodCall$Appender.apply(MethodCall.java:3506) at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod$WithBody.applyCode(TypeWriter.java:708) at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod$WithBody.applyBody(TypeWriter.java:693) at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod.apply(TypeWriter.java:600) at net.bytebuddy.dynamic.scaffold.TypeWriter$Default$ForInlining$WithFullProcessing$RedefinitionClassVisitor.onVisitEnd(TypeWriter.java:5022) at net.bytebuddy.utility.visitor.MetadataAwareClassVisitor.visitEnd(MetadataAwareClassVisitor.java:323) at net.bytebuddy.jar.asm.ClassReader.accept(ClassReader.java:722) at net.bytebuddy.jar.asm.ClassReader.accept(ClassReader.java:401) at net.bytebuddy.dynamic.scaffold.TypeWriter$Default$ForInlining.create(TypeWriter.java:3827) at net.bytebuddy.dynamic.scaffold.TypeWriter$Default.make(TypeWriter.java:2166) at net.bytebuddy.dynamic.scaffold.inline.RebaseDynamicTypeBuilder.make(RebaseDynamicTypeBuilder.java:252) at net.bytebuddy.dynamic.scaffold.inline.AbstractInliningDynamicTypeBuilder.make(AbstractInliningDynamicTypeBuilder.java:123) at net.bytebuddy.dynamic.DynamicType$Builder$AbstractBase.make(DynamicType.java:3595) at net.bytebuddy.dynamic.DynamicType$Builder$AbstractBase$Delegator.make(DynamicType.java:3819) at

Answer 1

在这种更复杂的方法体的情况下，我建议您在 Java 中编写代码并使用 MethodDelegation 或 Advice 来解决问题代码，然后 link 你的方法。

或者，您可以使用 StackManipulation 并从单个代码块构建方法。在这种情况下，您需要先构造一个数组，然后将此数组提供给方法，因为可变参数在字节代码级别不存在。

bytebuddy拦截方法中使用Methodcall有没有办法调用带字段的变长参数方法？

Is there a way to call a variable length parameter method with a field using Methodcall in bytebuddy intercept method?

java

reflection

byte-buddy