通过反思获得第一个父母的字段

我正在尝试获取对象的第一个父级的字段和值。 我目前的代码是这样的：

Class cls = obj.getClass(); Field[] fields = cls.getDeclaredFields(); for ( Field field : fields ) { String fieldName = field.getName(); String fieldValue = field.get(obj); } 

我的类结构与此类似：

 class A { int x; } class B extends A { int y; } class C extends B { int z; } 

现在，我将一个C对象传递给该方法，我想从C和B获取所有字段，但不是从A中获取。有没有办法做到这一点（使用reflection，我不想实现其他方法）？

Answer 1

Luchian使用getSuperclass（）方法获取对Class对象的引用，该Class对象表示相关对象的超类类型。 之后，您可以轻松地以与示例相同的方式获取字段。

Answer 2

创建一个方法

 public static void printFieldsFor(Class cls, Object obj) { Field[] fields = cls.getDeclaredFields(); for ( Field field : fields ) { String fieldName = field.getName(); String fieldValue = field.get(obj); } } printFieldsFor(object.getClass(), obj); printFieldsFor(object.getClass().getSuperclass(), obj); 

或使用循环

 for(Class cls = object.getClass(); cls!=null && cls!=A.class; cls = cls.getSuperclass()) { for(Field field : cls.getDeclaredFields()) { String fieldName = field.getName(); String fieldValue = field.get(obj); // do something with the field. } } 

Answer 3

 import java.lang.reflect.Field; import java.util.ArrayList; import java.util.Arrays; import java.util.List; /** * @author pablo.barbosa (2017-08-15) */ public class ReflectionUtil { /** * Hiding constructor. The methods are statics */ private ReflectionUtil() { // Hiding constructor } public static List getInheritedDeclaredFields(Class fromClass, Class stopWhenClass) { if (stopWhenClass == null) { stopWhenClass = Object.class; } List fields = new ArrayList<>(); List> classes = new ArrayList<>(); Class cls = fromClass; do { classes.add(cls); cls = cls.getSuperclass(); } while (cls != null && !cls.equals(stopWhenClass)); for (int i = classes.size() - 1; i >= 0; i--) { fields.addAll(Arrays.asList(classes.get(i).getDeclaredFields())); } return fields; } public static Field getInheritedDeclaredField(Class fromClass, String fieldName, Class stopWhenClass) throws NoSuchFieldException { if (stopWhenClass == null) { stopWhenClass = Object.class; } Class cls = fromClass; do { Field field; try { field = cls.getDeclaredField(fieldName); if (field != null) { return field; } } catch (NoSuchFieldException | SecurityException e) { // Nothing. We'll try to get field from superclass } cls = cls.getSuperclass(); } while (cls != null && !cls.equals(stopWhenClass)); // If we got here, we'll throw an exception throw new NoSuchFieldException(fieldName); } public static Object getInheritedDeclaredFieldValue(Object obj, String fieldName, Class stopWhenClass) throws NoSuchFieldException, IllegalAccessException { Field field = getInheritedDeclaredField(obj.getClass(), fieldName, stopWhenClass); field.setAccessible(true); return field.get(obj); } } 

Answer 4

您可以使用此代码从任何类中获取字段，而不是其父类或子类

 for (Field field : YourClassName.class.getDeclaredFields()) { //fields }