我有一個界面,可以說它看起來像這樣.

public interface TestObject {
    String getString();

    Long getLong();
}

我實(shí)際上想使用ByteBuddy構(gòu)建該對象的具體實(shí)現(xiàn).

這是我嘗試過的.

public class Runme {

    public static void main(String[] args) {
        ByteBuddy bb = new ByteBuddy();

        Class<?> clz = bb
                .subclass(TestObject.class)
      .method(any()).intercept(MethodDelegation.to(Interceptor.class))
            .make()
            .load(Object.class.getClassLoader(), ClassLoadingStrategy.Default.WRAPPER)
            .getLoaded();

    try {
        Object test = clz.newInstance();

    } catch (InstantiationException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }

}

public class Interceptor {

    public Object intercept(@Origin String method, @AllArguments Object[] args) throws Throwable {
        System.out.println("I have intercepted a call");

        return "Hello";

    }

}

}

我得到這個錯誤

Exception in thread "main" java.lang.IllegalArgumentException: None of [] allows for delegation from public boolean java.lang.Object.equals(java.lang.Object)
at net.bytebuddy.implementation.bind.MethodDelegationBinder$Processor.process(MethodDelegationBinder.java:881)
at net.bytebuddy.implementation.MethodDelegation$Appender.apply(MethodDelegation.java:1218)
at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod$WithBody.applyBody(TypeWriter.java:510)
at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod.apply(TypeWriter.java:444)
at net.bytebuddy.dynamic.scaffold.TypeWriter$Default$ForCreation.create(TypeWriter.java:3193)
at net.bytebuddy.dynamic.scaffold.TypeWriter$Default.make(TypeWriter.java:1481)
at net.bytebuddy.dynamic.scaffold.subclass.SubclassDynamicTypeBuilder.make(SubclassDynamicTypeBuilder.java:234)
at net.bytebuddy.dynamic.DynamicType$Builder$AbstractBase$AbstractDelegatingBuilder.make(DynamicType.java:2177)
at com.meta.testbytebuddy.Runme.main(Runme.java:22)
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:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)

我在做什么錯..如果我想實(shí)現(xiàn)多個接口怎么辦？

我正在使用ByteBuddy進(jìn)行代碼生成.

解決方法:

問題在于,您是通過MethodDelegation.to(Interceptor.class)委托給攔截器的靜態(tài)方法的,而攔截器類僅聲明了非靜態(tài)成員.您可以將攔截器方法聲明為靜態(tài)方法,也可以委托給實(shí)例而不是類.我認(rèn)為前一種方法會更合適.

但是,僅此一點(diǎn)仍然行不通.您正在從攔截器返回一個Object類型,與此同時(shí),您正在攔截any()方法.這包括您的TestObject接口的方法,還包括由Object(隱式超類)聲明的方法.您可以按以下方式定義攔截器,以使您的類得以編譯,但是Byte Buddy會將返回類型轉(zhuǎn)換為每個方法的返回類型,這將導(dǎo)致ClassCastException：

public class Interceptor {
  @RuntimeType
  public static Object intercept(@Origin String method, @AllArguments Object[] args) {
    System.out.println("I have intercepted a call");
    return "Hello";
  }
}