Java类加载工具--ClassUtil

jopen 8年前

介绍一个类加载工具,ClassUtil 需要加载类或资源的话可以使用该工具类。

    import java.io.InputStream;                        /**        * A utility class to assist with loading classes or resources by name. Many application servers use        * custom classloaders, which will break uses of:        * <pre>        *    Class.forName(className);        * </pre>        *        * This utility attempts to load the class or resource using a number of different mechanisms to        * work around this problem.        *        * @author Matt Tucker        */        public class ClassUtils {                            private static ClassUtils instance = new ClassUtils();                            /**            * Loads the class with the specified name.            *            * @param className the name of the class            * @return the resulting <code>Class</code> object            * @throws ClassNotFoundException if the class was not found            */            public static Class forName(String className) throws ClassNotFoundException {                return instance.loadClass(className);            }                            /**            * Loads the given resource as a stream.            *            * @param name the name of the resource that exists in the classpath.            * @return the resource as an input stream or <tt>null</tt> if the resource was not found.            */            public static InputStream getResourceAsStream(String name) {                return instance.loadResource(name);            }                            /**            * Not instantiatable.            */            private ClassUtils() {}                            public Class loadClass(String className) throws ClassNotFoundException {                Class theClass = null;                try {                    theClass = Class.forName(className);                }                catch (ClassNotFoundException e1) {                    try {                        theClass = Thread.currentThread().getContextClassLoader().loadClass(className);                    }                    catch (ClassNotFoundException e2) {                        theClass = getClass().getClassLoader().loadClass(className);                    }                }                return theClass;            }                            private InputStream loadResource(String name) {                InputStream in = getClass().getResourceAsStream(name);                if (in == null) {                    in = Thread.currentThread().getContextClassLoader().getResourceAsStream(name);                    if (in == null) {                        in = getClass().getClassLoader().getResourceAsStream(name);                    }                }                return in;            }        }