用反射改变属性的值

import java.lang.reflect.*;public class field2 {    public double d;    public static void main(String args[]) {        try {            Class cls = Class.forName("field2");            Field fld = cls.getField("d");//fld.isAccessible();//非public属性要加            field2 f2obj = new field2();            System.out.println("d = " + f2obj.d);            fld.setDouble(f2obj, 12.34);            System.out.println("d = " + f2obj.d);        } catch (Throwable e) {            System.err.println(e);        }    }}