解决方法是使用ByteBuddy的@FieldProxy
注解来替代通过javassist动态添加的方法注解。以下是代码示例:
import javassist.*;
import net.bytebuddy.ByteBuddy;
import net.bytebuddy.agent.ByteBuddyAgent;
import net.bytebuddy.description.annotation.AnnotationDescription;
import net.bytebuddy.dynamic.ClassFileLocator;
import net.bytebuddy.dynamic.DynamicType;
import net.bytebuddy.dynamic.loading.ClassLoadingStrategy;
import net.bytebuddy.implementation.FieldAccessor;
import net.bytebuddy.implementation.MethodDelegation;
import net.bytebuddy.matcher.ElementMatchers;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.reflect.Method;
public class ByteBuddyWithJavassistExample {
@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotation {
String value();
}
public static void main(String[] args) throws Exception {
// 使用javassist动态添加注解的示例
addAnnotationWithJavassist();
// 使用ByteBuddy的@FieldProxy注解来替代
addAnnotationWithByteBuddy();
}
private static void addAnnotationWithJavassist() throws Exception {
// 使用javassist动态添加注解
ClassPool pool = ClassPool.getDefault();
CtClass ctClass = pool.get("com.example.MyClass");
CtMethod ctMethod = ctClass.getDeclaredMethod("myMethod");
CtClass annotationClass = pool.get("com.example.MyAnnotation");
Annotation annotation = new Annotation(annotationClass);
annotation.addMemberValue("value", new StringMemberValue("Hello", annotationClass.getConstPool()));
ctMethod.getMethodInfo().addAttribute(annotation);
ctClass.writeFile();
// 使用反射查看注解是否添加成功
Class> myClass = ctClass.toClass();
Method myMethod = myClass.getDeclaredMethod("myMethod");
MyAnnotation myAnnotation = myMethod.getAnnotation(MyAnnotation.class);
System.out.println(myAnnotation.value()); // 输出:Hello
}
private static void addAnnotationWithByteBuddy() throws Exception {
// 使用ByteBuddy的@FieldProxy注解来替代
ByteBuddyAgent.install();
DynamicType.Builder
在上述代码中,首先使用javassist动态添加了一个方法注解@MyAnnotation("Hello")
,然后使用反射验证注解是否添加成功。接下来,使用ByteBuddy的@FieldProxy
注解来替代通过javassist动态添加的方法注解。在addAnnotationWithByteBuddy
方法中,使用ByteBuddy的API来构建一个新的类,并在方法上添加@MyAnnotation("Hello")
注解。最后,使用反射验证注解是否成功添加。