类反射得到类名，类变量，接口和注解

import java.lang.annotation.Annotation;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.List;
import static java.lang.System.out;

public class ClassDeclarationSpy {
    public static void main(String... args) {
        try {
            Class c = Class.forName(args[0]);
            out.format("Class:%n  %s%n%n", c.getCanonicalName());
            out.format("Modifiers:%n  %s%n%n",
                    Modifier.toString(c.getModifiers()));

            out.format("Type Parameters:%n");
            TypeVariable[] tv = c.getTypeParameters();
            if (tv.length != 0) {
                out.format("  ");
                for (TypeVariable t : tv)
                    out.format("%s ", t.getName());
                out.format("%n%n");
            } else {
                out.format("  -- No Type Parameters --%n%n");
            }

            out.format("Implemented Interfaces:%n");
            Type[] intfs = c.getGenericInterfaces();
            if (intfs.length != 0) {
                for (Type intf : intfs)
                    out.format("  %s%n", intf.toString());
                out.format("%n");
            } else {
                out.format("  -- No Implemented Interfaces --%n%n");
            }

            out.format("Inheritance Path:%n");
            List l = new ArrayList();
            printAncestor(c, l);
            if (l.size() != 0) {
                for (Class cl : l)
                    out.format("  %s%n", cl.getCanonicalName());
                out.format("%n");
            } else {
                out.format("  -- No Super Classes --%n%n");
            }

            out.format("Annotations:%n");
            Annotation[] ann = c.getAnnotations();
            if (ann.length != 0) {
                for (Annotation a : ann)
                    out.format("  %s%n", a.toString());
                out.format("%n");
            } else {
                out.format("  -- No Annotations --%n%n");
            }

            // production code should handle this exception more gracefully
        } catch (ClassNotFoundException x) {
            x.printStackTrace();
        }
    }

    private static void printAncestor(Class c, List l) {
        Class ancestor = c.getSuperclass();
        if (ancestor != null) {
            l.add(ancestor);
            printAncestor(ancestor, l);
        }
    }
}