使用反射读取字段的值。

/**from 时代Java公众号**/

/*

 *  PHEX - The pure-java Gnutella-servent.

 *  Copyright (C) 2001 - 2005 Phex Development Group

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

//package com.nowjava;

import java.lang.reflect.*;


public class Main {

    public static void main(String[] argv) throws Exception {

        Object obj = "nowjava.com";

        String fieldName = "nowjava.com";

        System.out.println(getFieldValue(obj, fieldName));

    }


    /**

     * Reads the value of a field.

     * @param obj the object to read the field value from. If it is a static field

     *            the object can be a instance of Class.

     */

    public static Object getFieldValue(Object obj, String fieldName) {

        try {

            Class clazz;

            if (obj instanceof Class) {

                clazz = (Class) obj;

            } else {

                clazz = obj.getClass();

            }

            Field field = clazz.getDecla