反射创建对象报错

[wscxy31415926]

package cn.pb.constructor;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.Calendar;



public class Main {
	public static void main(String[] args) throws SecurityException, NoSuchMethodException, IllegalArgumentException, InstantiationException, IllegalAccessException, InvocationTargetException {
		Class cla=Calendar.class;
		Calendar cal=(Calendar) cla.newInstance();
		System.out.println(cal.toString());
	}
}

运行时抛出java.lang.IllegalAccessException异常，求高手解答。

[想喝咖啡的貓]

protected Calendar()

[wscxy31415926]

[Quote=引用 1 楼 的回复:]
protected Calendar()
[/Quote]

package cn.pb.constructor;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.Calendar;



public class Main {
	public static void main(String[] args) throws SecurityException, NoSuchMethodException, IllegalArgumentException, InstantiationException, IllegalAccessException, InvocationTargetException {
		Class cla=Calendar.class;
		
		Constructor cons=cla.getConstructor();
		
		cons.setAccessible(true);
		Calendar cal=(Calendar) cons.newInstance();
		System.out.println(cal.toString());
	}
}

还是不行，这个问题很头痛，Constructor cons=cla.getConstructor();
我也换成过Constructor cons=cla.getDeclaredConstructor();
也是不行。

[杀手]

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Calendar;



public class Main {
    public static void main(String[] args) throws SecurityException, NoSuchMethodException, IllegalArgumentException, InstantiationException, IllegalAccessException, InvocationTargetException {
    	Class cla=Calendar.class;
        Method m= cla.getMethod("getInstance", null);
        Calendar calendar = (Calendar) m.invoke(cla, null);
        System.out.println(calendar.toString());
        
    }
}

由于Calendar的构造函数是protected所以是无法外部类访问他的构造函数的，故无法new出实例，你可以通过反射调用它的getInstance方法得到实例

[想喝咖啡的貓]

e...
我的意思是 你不能去newInstance一个非public的类构造器。

[wscxy31415926]

[Quote=引用 3 楼 的回复:]
Java code


import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Calendar;



public class Main {
……
[/Quote]

非常感谢！！！