使用反射和数组参数构造类的IllegalArgumentException

Question

运行以下代码:

public class Test {

    public Test(Object[] test){

    }

    public static void main(String[] args) throws Exception{
            Constructor cd = Test.class.getConstructor(Object[].class);
            Object[] objs = {1, 2, 3, 4, 5, 6, 7, 8};
            cd.newInstance(objs);
    }
}

我收到错误:

Exception in thread "main" java.lang.IllegalArgumentException: wrong number of arguments
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:532)
    at groupd.poker.utils.tests.ai.nqueens.Test.main(Test.java:17)

为什么是这样？

Answer 1

构造函数类的newInstance()方法接受一个对象数组.数组中的每个项都是您要调用的构造函数的参数.您的类的构造函数接受一个对象数组,因此您需要在传递给新实例方法的数组中包含一个对象数组

public static void main(String[] args) throws Exception{
            Constructor cd = Test.class.getConstructor(Object[].class);
            Object[] objs = {1, 2, 3, 4, 5, 6, 7, 8};
            Object[] passed = {objs};
            cd.newInstance(passed);
    }