Reads the value of a field using reflection. - Java Reflection

Java examples for Reflection:Field Value

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Description

Reads the value of a field using reflection.

Demo Code

/*/*from  w w  w . j a v a2  s  . c om*/
 *  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.java2s;
import java.lang.reflect.*;

public class Main {
    public static void main(String[] argv) throws Exception {
        Object obj = "java2s.com";
        String fieldName = "java2s.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.getDeclaredField(fieldName);
            field.setAccessible(true);
            return field.get(obj);
        } catch (Exception exp) {
            exp.printStackTrace();
            throw new RuntimeException(exp.getMessage());
        }
    }
}

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