如何使用varargs和反射 [英] How to work with varargs and reflection
本文介绍了如何使用varargs和反射的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
简单的问题,该代码是如何工作的?
Simple question, how make this code working ?
public class T {
public static void main(String[] args) throws Exception {
new T().m();
}
public // as mentioned by Bozho
void foo(String... s) {
System.err.println(s[0]);
}
void m() throws Exception {
String[] a = new String[]{"hello", "kitty"};
System.err.println(a.getClass());
Method m = getClass().getMethod("foo", a.getClass());
m.invoke(this, (Object[]) a);
}
}
输出:
class [Ljava.lang.String;
Exception in thread "main" java.lang.IllegalArgumentException: wrong number of arguments
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
推荐答案
Test.class.getDeclaredMethod("foo", String[].class);
有效。问题是 getMethod(..)
只搜索 public
方法。来自javadoc:
works. The problem is that getMethod(..)
only searches the public
methods. From the javadoc:
返回一个Method对象,该对象反映此Class对象所表示的类或接口的指定公共成员方法。
Returns a Method object that reflects the specified public member method of the class or interface represented by this Class object.
更新:成功获取方法后,您可以使用以下方法调用它:
Update: After successfully getting the method, you can invoke it using:
m.invoke(this, new Object[] {new String[] {"a", "s", "d"}});
即 - 创建一个新的对象
数组使用一个元素 - String
数组。使用您的变量名称,它将如下所示:
that is - create a new Object
array with one element - the String
array. With your variable names it would look like:
m.invoke(this, new Object[] {a});
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