android class newinstance 构造函数 参数,反射newinstance构造函数java错误参数的数量

我正在学习Java中的Reflection，并尝试构造一个Constructor的例子。但是有一个问题：“错误的参数”。 通过谷歌和stackoverflow搜索，我找不到我目前面临的同样的问题。 任何人都可以请帮我理解这个问题，非常感谢。 这是我的代码：反射newinstance构造函数java错误参数的数量

public static void main(String[] args) {

PrintClass f = new PrintClass();

Class cl = f.getClass();

Constructor> constructor[] = cl.getDeclaredConstructors(); // cl.getDeclaredConstructors() also won't work...

f.field1 = 3;

PrintClass p1 = null;

PrintClass p2 = null;

try {

p1 = (PrintClass) constructor[0].newInstance(); // constructor[0].newInstance((Object[])args) also won't work...

p2 = (PrintClass) constructor[1].newInstance("this is not PrintClass-------");

p1.print();

p2.print();

} catch (InstantiationException | IllegalAccessException

| IllegalArgumentException | InvocationTargetException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

class PrintClass {

String s = "this is PrintClass...";

int field1;

public PrintClass(String s) {

this.s = s;

}

public PrintClass() {

}

public void print() {

System.out.println(s);

}

}

，这是错误

java.lang.IllegalArgumentException: wrong number of arguments

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)

at java.lang.reflect.Constructor.newInstance(Unknown Source)

at reflection.MainClass.main(MainClass.java:18)

再次感谢你这么多帮助我理解这个问题。 :)

2015-05-12

zoro