Javassist将注释设置为超类字段

Question

How to set annotation to superclass field ? For the code i have i see only the annotation is set to domain but not to name field which belongs to superclass when i do ctClass.toClass()

class A {
   private String name;
}

Class B extends A {
   private String domain;
}

getFields(ctClass).forEach(f -> {
    final AnnotationsAttribute attr = new AnnotationsAttribute(cpool, AnnotationsAttribute.visibleTag);
    final Annotation annot = new Annotation(Indexed.class.getName(), cpool);
    attr.addAnnotation(annot);
    f.getFieldInfo().addAttribute(attr);
});

List<CtField> getFields(CtClass ctClass) throws NotFoundException {
    final List<CtField> fields = new LinkedList<CtField>();
    fields.addAll(Arrays.asList(ctClass.getDeclaredFields()));
    while (ctClass.getSuperclass() != null) {
        ctClass = ctClass.getSuperclass();
        fields.addAll(Arrays.asList(ctClass.getDeclaredFields()));
    }
    return fields;
}

Answer 1

You need to use the constant pool table of the class declaring the method. Also you should use the getAttribute(..) to obtain the annotations attribute, if you create a new one, the current annotations are erased.

The for each can execute something similar to:

fieldsByClass.forEach(ctField -> {
    CtClass ctClass = ctField.getDeclaringClass();
    ClassFile classFile = ctClass.getClassFile();
    ConstPool constPool = classFile.getConstPool();
    FieldInfo fieldInfo = ctField.getFieldInfo();
    AnnotationsAttribute annotationsAttribute = (AnnotationsAttribute) fieldInfo
            .getAttribute(AnnotationsAttribute.visibleTag);
    Annotation annotation = new Annotation(Deprecated.class.getName(), constPool);
    annotationsAttribute.addAnnotation(annotation);
    ctField.getFieldInfo().addAttribute(annotationsAttribute);
});

Note: you should be careful with the classes that you modify, if one of the classes extends a java class that has a field defined this will fail.