学步园

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

public class GenericsUtils {
/**
     * Locates the first generic declaration on a class.
     *
     * @param clazz The class to introspect
     * @return the first generic declaration, or <code>null</code> if cannot be determined
*/
public static Class<?> getGenericClass(Class<?> clazz) {
return getGenericClass(clazz, 0);
    }

public static Class<?> getGenericClass(Class<?> clazz, int index) {
        Type genType = clazz.getGenericSuperclass();

if (genType instanceof ParameterizedType) {
            Type[] params = ((ParameterizedType) genType).getActualTypeArguments();

if ((params != null) && (params.length >= (index - 1))) {
return (Class<?>) params[index];
            }
        }
return null;
    }
}