如何使用Java迭代类及其成员类的对象

Question

I'm trying to get all the data objects(variables alone, not its functions et al) of one class ( objectfactory.java ) and also, invoke the methods in itself, that create instances of other classes in the same package, and this way, make a list of all the objects in all the classes in a given package. (to put things in perspective, these are classes created by JAXB).

That is, what I basically want to do is, iterate through, and make a list of all the data objects of:

Objectfactory, and then,
- Person
- Name
- Url
- Link
- Personnel

classes.

Here is the objectFactory class:

@XmlRegistry
public class ObjectFactory {

    private final static QName _Given_QNAME = new QName("", "given");
    private final static QName _Email_QNAME = new QName("", "email");
    private final static QName _Family_QNAME = new QName("", "family");

    /**
     * Create a new ObjectFactory that can be used to create new instances of schema derived classes for package: schema
     * 
     */
    public ObjectFactory() {
    }
    public Person createPerson() {
        return new Person();
    }

    public Name createName() {
        return new Name();
    }

    public Url createUrl() {
        return new Url();
    }

    public Link createLink() {
        return new Link();
    }

    public Personnel createPersonnel() {
        return new Personnel();
    }

    @XmlElementDecl(namespace = "", name = "given")
    public JAXBElement<String> createGiven(String value) {
        return new JAXBElement<String>(_Given_QNAME, String.class, null, value);
    }
    @XmlElementDecl(namespace = "", name = "email")
    public JAXBElement<String> createEmail(String value) {
        return new JAXBElement<String>(_Email_QNAME, String.class, null, value);
    }

    @XmlElementDecl(namespace = "", name = "family")
    public JAXBElement<String> createFamily(String value) {
        return new JAXBElement<String>(_Family_QNAME, String.class, null, value);
    }

}

I could go directly only until the fields and methods in ObjectFactory using Java Reflections.(getDeclaredFields()) etc.

But, for the other classes, I can only manually reach their objects. (For eg, for Class Link)

ObjectFactory factory= new ObjectFactory();
Field[] fields = factory.createLink().getClass().getDeclaredFields();

        Field[] fields1 = factory.createPerson().getClass().getDeclaredFields();

        for (Field f1 : fields1) {
            System.out.println("field name = " + f1.getName()); 
        }

but, I want to do this at runtime for all the classes in objectfactory, and not manually by making calls like "createPerson()".

I tried doing something like this;

ObjectFactory factory= new ObjectFactory();
  Method[] methods = factory.getClass().getDeclaredMethods();
     for (Method m : methods) {
System.out.println("Class name = " + m.getName()); 
        Field[] subfields = m.getClass().getDeclaredFields();


        for (Field sf : subfields) {
            System.out.println("entities = " + sf.getName()); 
        }
        System.out.println("\n\n");

    }

But this doesn't work.

My expected output would be something like this:

Class name = ObjectFactory
    field name = _Given_QNAME
    field name = _Email_QNAME
    field name = _Family_QNAME

Class name = Person
    field name = Name
    field name = Age
    field name = Sex

Class name = Personnel
    field name = address
 ...

and so on..

How do I do this?

Answer 1

public void getAllClassAndFields() {
    ObjectFactory objectFactory = new ObjectFactory();
    Method[] methods = objectFactory.getClass().getDeclaredMethods();
    for (Method method : methods) {
        try {
            // Check if method have XmlElementDecl annotation
            XmlElementDecl annotation = method.getAnnotation(XmlElementDecl.java);
            if (annotation == null) {
                // Invoke method only if it is not annoatated with XmlElementDecl 
                Object object = method.invoke(objectFactory, new Object[] {});
                System.out.println("Class Name = " + object.getClass().getName());
                printFileds(object);
            }

        } catch (Exception e) {
          // I used Exception to keep it simple, instead use appropriate exception types here 
        } 
    }
}

public static void printFileds(Object obj) {
    Field[] fields = obj.getClass().getFields();
    for (Field field : fields) {
        System.out.println("Field Name = " + field.getName());
    }
}

Answer 2

Not sure why do you want to do this?
But try the code below

public class RelectionTestCases {
public static final String INDENT = "    ";

public static void main(String[] args) throws IllegalArgumentException, IllegalAccessException, InvocationTargetException {
    ObjectFactory factory = new ObjectFactory();

    Field[] fields = ObjectFactory.class.getDeclaredFields();

    // Fields
    System.out.println(ObjectFactory.class.getName());
    for (Field field : fields) {
        System.out.println(INDENT + field.getName());
    }

    // Method
    Method[] methods = ObjectFactory.class.getDeclaredMethods();
    for (Method method : methods) {

        if (method.getReturnType().equals(JAXBElement.class)) {
            continue;
        }

        Object object = method.invoke(factory, null);
        System.out.println(object.getClass().getName());

        Field[] subFields = object.getClass().getDeclaredFields();

        for (Field field : subFields) {
            System.out.println(INDENT + field.getName());
        }
    }
}

}