Create a new instance given a class name : Class Method Field Name « Reflection « Java






Create a new instance given a class name

 
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.net.MalformedURLException;
import java.net.URL;

/**
 * A collection of class management utility methods.
 *
 * @version $Id: ClassUtils.java 587751 2007-10-24 02:41:36Z vgritsenko $
 */
public class ClassUtils {

    /**
     * Create a new instance given a class name
     *
     * @param className A class name
     * @return A new instance
     * @exception Exception If an instantiation error occurs
     */
    public static Object newInstance(String className) throws Exception {
        return loadClass(className).newInstance();
    }

    /**
     * Load a class given its name.
     * BL: We wan't to use a known ClassLoader--hopefully the heirarchy
     *     is set correctly.
     *
     * @param className A class name
     * @return The class pointed to by <code>className</code>
     * @exception ClassNotFoundException If a loading error occurs
     */
    public static Class loadClass(String className) throws ClassNotFoundException {
        return getClassLoader().loadClass(className);
    }

    /**
     * Return a resource URL.
     * BL: if this is command line operation, the classloading issues
     *     are more sane.  During servlet execution, we explicitly set
     *     the ClassLoader.
     *
     * @return The context classloader.
     * @exception MalformedURLException If a loading error occurs
     */
    public static URL getResource(String resource) throws MalformedURLException {
        return getClassLoader().getResource(resource);
    }

    /**
     * Return the context classloader.
     * BL: if this is command line operation, the classloading issues
     *     are more sane.  During servlet execution, we explicitly set
     *     the ClassLoader.
     *
     * @return The context classloader.
     */
    public static ClassLoader getClassLoader() {
        return Thread.currentThread().getContextClassLoader();
    }
}

   
  








Related examples in the same category

1.Load a class given its name.
2.Get the short name of the specified class by striping off the package name.
3.Returns an instance of the given class name, by calling the default constructor.
4.Get non Package Qualified Name
5.Returns the name of a class without the package name
6.Returns the package portion of the specified class
7.Format a string buffer containing the Class, Interfaces, CodeSource, and ClassLoader information for the given object clazz.
8.Create a unique hash for Constructor and method