意外的 Class.getMethod 行为 [英] Unexpected Class.getMethod behaviour

问题描述

不久前我有一个类似的问题使用 Class.getMethod 和自动装箱，在您自己的查找算法中实现它是有意义的.但真正让我感到困惑的是以下内容也不起作用:

A while ago I had a similar question when using Class.getMethod and autoboxing, and it made sense to implement this in your own lookup algorithm. But what really confused me a little was that the following is not working either:

public class TestClass
{
    public String doSomething(Serializable s)
    {
        return s.toString();
    }

    public static void main(String[] args) throws SecurityException, NoSuchMethodException
    {
        TestClass tc = new TestClass();
        Method m = tc.getClass().getMethod("doSomething", String.class);
    }
}

String.class 实现了 Serializable 接口，我真的希望它包含在查找方法中.在我自己的查找算法中是否也必须考虑这一点?

String.class implements the Serializable interface and I really expected it to be included in the lookup method. Do I have to consider this in my own lookup algorithms as well?

编辑:我确实阅读了 Javadoc，所以让我强调问题的第二部分:如果是这样，您是否有关于如何快速做到这一点的建议(我已经不得不添加一些自定义匹配和转换算法，但我不希望它变得太慢)?

EDIT: I did read the Javadoc, so let me emphasise the second part of the question: And if so do you have suggestions on how to do that fast (I already had to add some custom matching and converting algorithms and I don't want it to get too slow)?

推荐答案

根据您的编辑，您可以使用 Class#isAssignableFrom().这是一个基本的启动示例(将明显的(运行时)异常处理放在一边):

As per your edit, you can make use of Class#isAssignableFrom(). Here's a basic kickoff example (leaving obvious (runtime) exception handling aside):

package com.stackoverflow.q2169497;

import java.io.Serializable;
import java.lang.reflect.Method;

public class Test {

    public String doSomething(Serializable serializable) {
        return serializable.toString();
    }

    public static void main(String[] args) throws Exception {
        Test test = new Test();
        for (Method method : test.getClass().getMethods()) {
            if ("doSomething".equals(method.getName())) {
                if (method.getParameterTypes()[0].isAssignableFrom(String.class)) {
                    System.out.println(method.invoke(test, "foo"));
                }
            }
        }
    }

}

这应该将 foo 打印到标准输出.

This should print foo to stdout.

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