我反射时如何知道最后一个物体？

Question

I have a DTO like this,

ADto{
  BDto bDto;
  Cto cDto;
}

BDto{
  String a1;
  String b1;
  int b1;
}

CDto{
  String a2;
  String b2;
  int b2;
}

When I use reflect,I want to get the BDto and CDto in ADto Object.Code like this:

 for (Field field : aObj.getClass().getDeclaredFields()) {
            try {
                Object fieldValue = field.get(object);
 //todo  how to collect all String value  in `BDto` and `CDto` of aObj
                if (fieldValue instanceof String) {
                    shouldCheckFieldValues.add((String) fieldValue);
                }
            } catch (Exception e) {
                logger.error("some error has happened when fetch data in loop", e);
            }

        }
    }

I want to collect all String value in BDto and CDto of aObj?How can I achieve this? Or how can I know the field which I have to recursive traversal with no hard code?

Answer 1

You directly try to get the String attributes from ADto class, you can't.

First get the BDto attribute, then retreive Strings attributes. Do the same for CDto attribute

for (Field field : aObj.getClass().getDeclaredFields()) {
        try {
            Object fieldValue = field.get(object);
            //todo  how to collect all String value  in `BDto` and `CDto` of aObj
            if (fieldValue instanceof BDto) {
                for (Field field2 : fieldValue.getClass().getDeclaredFields()) 
                    if (field2 instanceof String) {
                        shouldCheckFieldValues.add((String) field2 );

Answer 2

Hope this helps

static void exploreFields(Object aObj) {
    for (Field field : aObj.getClass().getDeclaredFields()) {

        try {
            Object instance_var = field.get(aObj);
            if (instance_var instanceof String) {
                System.out.println(instance_var);

            } else if(!(instance_var instanceof Number)) {
                exploreFields(instance_var);
            }
        } catch (Exception e) {
            logger.error("some error has happened when fetch data in loop", e);
        }
    }
}

Edited based on comment. Be aware your objects should not have circular dependencies.