字节伙伴将实例方法委托给 static 方法，将实例作为参数传递

Question

我想知道是否使用 byte-buddy 我可以在 class 中创建方法

public class Foo {

  //some fields and getters 

  public String newMethod() {
    return FooPrinter.createCustomToString(this);
  }
}

这样它就会调用

public class FooPrinter() {
  public static String createCustomToString(Foo foo) {
     return foo.getSomeField() + " custom string";
  }
}

我努力了

builder
    .defineMethod("newMethod", String.class, Ownership.MEMBER, Visibility.PUBLIC)
    .intercept(MethodDelegation.to(FooPrinter.class))

并将 @This 添加到@This中的参数，但我收到异常，即FooPrinter中的非方法允许来自FooPrinter Foo.bar()的委托。

Answer 1

您的设置必须有其他内容，这可以按预期工作：

import net.bytebuddy.description.modifier.Ownership;
import net.bytebuddy.description.modifier.Visibility;
import net.bytebuddy.implementation.MethodDelegation;
import net.bytebuddy.implementation.bind.annotation.This;

public class Sample {

    public static void main(String[] args) throws Exception {
        Foo instance = new ByteBuddy().subclass(Foo.class)
                .defineMethod("newMethod", String.class, Visibility.PUBLIC)
                .intercept(MethodDelegation.to(FooPrinter.class))
                .make()
                .load(Foo.class.getClassLoader())
                .getLoaded()
                .getConstructor()
                .newInstance();

        Object result = instance.getClass().getMethod("newMethod").invoke(instance);
        System.out.println(result);
    }

    public static class Foo {
        public String getSomeField() {
            return "someField";
        }
    }

    public static class FooPrinter {
        public static String createCustomToString(@This Foo foo) {
            return foo.getSomeField() + " custom string";
        }
    }
}

将打印someField 自定义字符串。