获取声明的方法 - Java [英] Getting Declared Methods - Java

问题描述

假设我有以下三个类别

A.java

public class A {
    public static void main (String[] args) {
        new C();
    }
}

B.java / p>

B.java

import java.lang.reflect.Method;
import java.util.Arrays;

public class B {
    public B() {
        Method[] m = this.getClass().getDeclaredMethods();
        System.out.println(Arrays.toString(m));
    }

    public void hello() {

    }
}

C.java

public class C extends B{
    public C() {
        super();
    }
}

我在类A中运行main方法。 ，它应该实例化类C，它应该调用类B的构造函数，打印出声明的方法。输出为 [] 。这是一个惊喜，因为我期待的输出是（假设所有的类都在包中称为 test ）：

and I run the main method in class A. Well, it should instantiate class C, which in turn should call class B's constructor, to print out the declared methods. The output is []. This is a surprise to me, as I was expecting the output to be (assuming all classes are in package called test):

[public void test.B.hello()]

那么，怎么了？

推荐答案

getClass 返回实例的类。在这种情况下，这是 C 。类 C 中没有声明的方法。您也可以使用返回的 Class 对象的'getSuperClass'方法来解决您的问题：

getClass returns the class of the instance. In this case, this is C. There is no declared method in class C. You can solve your problem by also using the 'getSuperClass' method of the returned Class object:

Class c = this.getClass();
while (c != null) {
  System.out.println(Arrays.toString(c.getDeclaredMethods()));
  c = c.getSuperClass();
}

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