Here you can find the source of find(String executable, File... dirs)
| Parameter | Description |
|---|---|
| executable | the name of the program to find, generally without the extension |
| dirs | optional set of directories in which the program need to be searched before checking the system's path. |
public static File find(String executable, File... dirs)
//package com.java2s; /*//from w ww.j av a 2 s .c om * #%L * Wisdom-Framework * %% * Copyright (C) 2013 - 2014 Wisdom Framework * %% * Licensed 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. * #L% */ import java.io.File; public class Main { /** * The set of extensions (including the empty extension) to append to the searched executable name. */ public static final String[] EXECUTABLE_EXTENSIONS = new String[] { // The command itself (no extension) "", // Linux and Unix (scripts) ".sh", ".bash", // Windows ".exe", ".bat", ".cmd" }; /** * Tries to find an executable with the given name. It first checks in of the given directories (if any) and * then tries in the system's path. The lookup tries several extensions (.sh, .bash, .exe. .cmd. and .bat). * * @param executable the name of the program to find, generally without the extension * @param dirs optional set of directories in which the program need to be searched before checking the system's * path. * @return the executable's file, {@code null} if not found */ public static File find(String executable, File... dirs) { // First try using the hints. if (dirs != null) { for (File hint : dirs) { File file = findExecutableInDirectory(executable, hint); if (file != null) { return file; } } } // Not found, try to use the system path. return findExecutableInSystemPath(executable); } /** * Tries to find the given executable (specified by its name) in the given directory. It checks for a file having * one of the extensions contained in {@link #EXECUTABLE_EXTENSIONS}, and checks that this file is executable. * * @param executable the name of the program to find, generally without the extension * @param directory the directory in which the program is searched. * @return the file of the program to be searched for if found. {@code null} otherwise. If the given directory is * {@code null} or not a real directory, it also returns {@code null}. */ public static File findExecutableInDirectory(String executable, File directory) { if (directory == null || !directory.isDirectory()) { // if the directory is null or not a directory => returning null. return null; } for (String extension : EXECUTABLE_EXTENSIONS) { File file = new File(directory, executable + extension); if (file.isFile() && file.canExecute()) { return file; } } // Not found. return null; } /** * Tries to find the given executable (specified by its name) in the system's path. It checks for a file having * one of the extensions contained in {@link #EXECUTABLE_EXTENSIONS}, and checks that this file is executable. * * @param executable the name of the program to find, generally without the extension * @return the file of the program to be searched for if found. {@code null} otherwise. */ public static File findExecutableInSystemPath(String executable) { String systemPath = System.getenv("PATH"); // Fast failure if we don't have the PATH defined. if (systemPath == null) { return null; } String[] pathDirs = systemPath.split(File.pathSeparator); for (String pathDir : pathDirs) { File dir = new File(pathDir); if (dir.isDirectory()) { File file = findExecutableInDirectory(executable, dir); if (file != null) { return file; } } } // :-( return null; } }