Java Reflection Field Value Set setFieldValue(Class clazz, String fieldName, Object value)

Description

Set static field value.

License

Open Source License

Parameter

Parameter	Description
clazz	the class
fieldName	the field name
value	the value

Declaration

public static void setFieldValue(Class<?> clazz, String fieldName, Object value) 

Method Source Code

//package com.java2s;
/*//  ww  w .  j a v a  2  s.co m
 * JBoss, Home of Professional Open Source.
 * Copyright 2011, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

import java.lang.reflect.Field;

public class Main {
    /**
     * Set field value.
     * 
     * @param target the target
     * @param fieldName the field name
     * @param value the value
     */
    public static void setFieldValue(Object target, String fieldName, Object value) {
        if (target == null)
            throw new IllegalArgumentException("Null target");

        final Field field = findField(target.getClass(), fieldName);
        try {
            field.set(target, value);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Set static field value.
     * 
     * @param clazz the class
     * @param fieldName the field name
     * @param value the value
     */
    public static void setFieldValue(Class<?> clazz, String fieldName, Object value) {
        final Field field = findField(clazz, fieldName);
        try {
            field.set(null, value);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Find field.
     *
     * @param clazz the class
     * @param fieldName the field name
     * @return field instance
     */
    private static Field findField(Class<?> clazz, String fieldName) {
        if (clazz == null)
            throw new IllegalArgumentException("Null class");
        if (fieldName == null)
            throw new IllegalArgumentException("Null field name");

        try {
            Class<?> current = clazz;
            while (current != null) {
                try {
                    final Field f = current.getDeclaredField(fieldName);
                    f.setAccessible(true);
                    return f;
                } catch (NoSuchFieldException ignored) {
                }
                current = current.getSuperclass();
            }
        } catch (Throwable t) {
            throw new RuntimeException(t);
        }
        throw new IllegalStateException("Couldn't find field: " + clazz.getName() + " / " + fieldName);
    }
}

Related

1. setFieldValue(Class clazz, Object instance, String fieldName, T value)
2. setFieldValue(Class clazz, Object target, String fieldName, Object value)
3. setFieldValue(Class clazz, E instance, Object value, String... names)
4. setFieldValue(Class clazz, Object entity, String fieldName, V value)
5. setFieldValue(Class clazz, String fieldName, Object value)
6. setFieldValue(Class expectedType, Object target, String fieldName, T value)
7. setFieldValue(Field f, Object target, Object value)
8. setFieldValue(Field field, Object instance, T value)
9. setFieldValue(Field field, Object obj, Object value)