为什么Class.isLocalClass总是Boolean.FALSE？ [英] Why does Class.isLocalClass always Boolean.FALSE?

问题描述

我有一个简单的方法，它总是返回-undefined - 。

I've got a simple Method that returns me always "-undefined-".

public static String getStereoType(Class<?> clazz) {
    String result = "-undefined-";
    if (clazz.isEnum()) {
        result = "enum";
    } else if (clazz.isInterface()) {
        result = "interface";
    } else if (clazz.isLocalClass() || clazz.isMemberClass()) {
        result = "class";
    }
    return result;
}

当我用Object.class或Long.class调用此方法时，总是结果-undefined - 。

When I call this Method with Object.class or Long.class always is the result "-undefined-".

 List<Class<?>> superClazzes = ClassUtil.getSuperClazzList(clazz);
    for (Class<?> c: superClazzess){
        String stereoType = ClassUtil.getStereoType(c.getClass());
        }

public static List<Class<?>> getSuperClazzList(Class<?> clazz) {
        List<Class<?>> resultList = new ArrayList<Class<?>>();
        Class<?> superClass = clazz.getSuperclass();
        if (superClass != null) {
            resultList.add(superClass);
            resultList.addAll(getSuperClazzList(superClass));
        }
        return resultList;
    }

推荐答案

回答你的问题title， isLocalClass（） 总是返回 false ：它返回<$ c $对于在方法中声明的类型，c> true 。类似地， isMemberClass（）对于在另一种类型中声明的类型返回 true 。

To answer the question in your title, isLocalClass() does not always return false: it returns true for types declared within a method. Similarly, isMemberClass() returns true for types declared within another type.

考虑：

public class Outer {

    interface MemberClass {}

    public static void main(String[] args) {
        class LocalClass {}

        System.out.printf(
            "%s/%s%n",
            LocalClass.class.isLocalClass(),
            LocalClass.class.isMemberClass()
        );

        System.out.printf(
            "%s/%s%n",
            MemberClass.class.isLocalClass(),
            MemberClass.class.isMemberClass()
        );
    }
}

此代码执行时打印出 true / false 后跟 false / true 。它们一起只计算在另一个类中或在方法中定义的类型。严格取决于目标类型是类而不是接口或枚举，所以你不能用它来过滤。

This code, when executed, prints out true/false followed by false/true. Together, they only account for types which are defined within another class, or within a method. Neither strictly depends on the target type being a class as opposed to an interface or enum, so you cannot use it to filter that way.

请参阅@ Tarion对 应该的方法的出色答案接受（并接受他的答案，因为它更能完全解决你的问题）。

See @Tarion's excellent answer for the approach you should be taking (and accept his answer, as it more completely solves your problem).

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