Java/Development Class/Class Path
Содержание
getClass().getResourceAsStream
<source lang="java"> // This example is from the book _Java AWT Reference_ by John Zukowski.
// Written by John Zukowski. Copyright (c) 1997 O"Reilly & Associates. // You may study, use, modify, and distribute this example for any purpose. // This example is provided WITHOUT WARRANTY either expressed or import java.applet.Applet; import java.awt.Font; import java.awt.Graphics; import java.awt.Image; import java.io.IOException; import java.io.InputStream; import java.net.URL; import java.util.Properties; public class Prop11 extends Applet {
Image im; Font f; String msg; public void paint(Graphics g) { g.setFont(f); if (im != null) g.drawImage(im, 50, 100, this); if (msg != null) g.drawString(msg, 50, 50); } public void init() { InputStream is = getClass().getResourceAsStream("prop11.list"); Properties p = new Properties(); try { p.load(is); f = Font.decode(p.getProperty("MyProg.font")); msg = p.getProperty("MyProg.message"); String name = p.getProperty("MyProg.image"); URL url = getClass().getResource(name); im = getImage(url); } catch (IOException e) { System.out.println("error loading props..."); } }
} File: prop11.list MyProg.font.size=20 MyProg.font.type=italic-bold MyProg.font.name=Helvetica MyProg.message=Hello World
</source>
Load resource file: absolute from the classpath
<source lang="java">
import java.io.IOException; import java.net.URL; public class Main {
public static void main(String[] args) throws IOException { // absolute from the classpath URL url = Main.class.getResource("/mypackage/foo.txt"); }
}
</source>
Load resource file: relative to the class location
<source lang="java">
import java.io.IOException; import java.net.URL; public class Main {
public static void main(String[] args) throws IOException { // relative to the class location URL url = Main.class.getResource("foo.txt"); }
}
</source>
relative document loading in classpath
<source lang="java">
import java.io.IOException; import java.net.URL; public class Main {
public static void main(String[] args) throws IOException { // relative document URL url = Main.class.getResource("docs/bar.txt"); }
}
</source>
Try adding one or more item(s) to class path
<source lang="java">
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002. * All rights reserved. Software written by Ian F. Darwin and others. * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $ * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS"" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee * cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s, * pioneering role in inventing and promulgating (and standardizing) the Java * language and environment is gratefully acknowledged. * * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for * inventing predecessor languages C and C++ is also gratefully acknowledged. */
import java.util.Properties; /**
* Try adding one or more item(s) to class path. */
public class SysPropSet {
static Properties p = System.getProperties(); public static void main(String[] argv) { System.out.println("System Properties:"); System.out.println("java.class.path now = " + getClassPath()); p.setProperty("java.class.path", getClassPath() + ";" + "C:/jdk1.2/lib/tools.jar"); System.out.println("java.class.path now = " + getClassPath()); try { Class.forName("sun.tools.javap.JavaP"); } catch (Exception e) { System.err.println(e); return; } System.out.println("Got it!!"); } static String getClassPath() { return p.getProperty("java.class.path", null); }
}
</source>