我有一个java swing应用程序，想使用我在网上找到的AppLoader.java类进行自动更新
有任何人对这门课程有过任何经验。我似乎无法使用我的应用程序实现此类并且出现错误： java.io.FileNotFoundException：C：\ Users \ home \ Documents \ NetBeansProjects \ test_update \ build \ classes（访问被拒绝）
和
java.lang.RuntimeException：找不到主Jar！
答案 0 :(得分：0)
复制并粘贴下面的代码并运行
import java.io. ; import java.lang.reflect.Method; import java.net。; import java.text。; import java.util.jar。; import javax.swing。*; import java.util.zip .GZIPInputStream;
/**
* This app
*/
public class AppLoader {
// Constants
static final String AppDirName = "SnapCode";
static final String JarName = "SnapCode1.jar";
static final String JarURL = "http://reportmill.com/snap1/SnapCode1.jar.pack.gz";
static final String MainClass = "snap.app.App";
/**
* Main method - reinvokes main1() on Swing thread in exception handler.
*/
public static void main(final String args[]) {
// Invoke real main with exception handler
try {
main1(args);
} catch (Throwable e) {
JOptionPane.showMessageDialog(null, e.toString());
e.printStackTrace();
}
}
/**
* Main method: - Gets main Jar file from default, if missing - Updates main
* Jar file from local update file, if previously loaded - Load main Jar
* into URLClassLoader, load main class and invoke main method - Check for
* update from remove site in background
*/
public static void main1(final String args[]) throws Exception {
// Make sure default jar is in place
try {
copyDefaultMainJar();
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e.toString());
e.printStackTrace();
}
// If Update Jar exists, copy it into place
File jar = getAppFile(JarName);
File updateJar = getAppFile(JarName + ".update");
if (updateJar.exists()) {
copyFile(updateJar, jar);
jar.setLastModified(updateJar.lastModified());
updateJar.delete();
}
// If jar doesn't exist complain bitterly
if (!jar.exists() || !jar.canRead())
throw new RuntimeException("Main Jar not found!");
// Check for updates in background thread
if (args.length == 0 || !args[0].equals("-snap"))
new Thread(new Runnable() {
public void run() {
checkForUpdatesSilent();
}
}).start();
// Create URLClassLoader for main jar file, get App class and invoke
// main
// URLClassLoader ucl = new URLClassLoader(
// new URL[] { jar.toURI().toURL() });
// Class cls = ucl.loadClass(MainClass); // ucl.close();
// Method meth = cls.getMethod("main", new Class[] { String[].class });
// meth.invoke(null, new Object[] { args });
// if (cls == Object.class)
// ((Closeable) ucl).close(); // Getting rid of warning message for ucl
}
/**
* Copies the default main jar into place for initial run.
*/
private static void copyDefaultMainJar() throws IOException, ParseException {
// Get main jar from app package and get location of working jar file
URL url = AppLoader.class.getProtectionDomain().getCodeSource()
.getLocation();
String path0 = url.getPath();
path0 = URLDecoder.decode(path0, "UTF-8");
path0 = path0 + "SnapCode1.jar.pack.gz" ;
File jar0 = getAppFile(JarName);
File jar1 = new File(path0);
// If app package main jar is newer, copy it into place and set time
if (jar0.exists() && jar0.lastModified() >= jar1.lastModified())
return;
copyFile(jar1, jar0);
}
/**
* Check for updates.
*/
private static void checkForUpdatesSilent() {
try {
checkForUpdates();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Check for updates.
*/
private static void checkForUpdates() throws IOException,
MalformedURLException {
// Get URL connection and lastModified time
File jarFile = getAppFile(JarName);
URL url = new URL(JarURL);
URLConnection connection = url.openConnection();
long mod0 = jarFile.lastModified(), mod1 = connection.getLastModified();
if (mod0 >= mod1) {
System.out.println("No update available at " + JarURL + '(' + mod0
+ '>' + mod1 + ')');
return;
}
// Get update file and write to JarName.update
System.out.println("Loading update from " + JarURL);
byte bytes[] = getBytes(connection);
System.out.println("Update loaded");
File updatePacked = getAppFile(JarName + ".pack.gz"), updateFile = getAppFile(JarName
+ ".update");
writeBytes(updatePacked, bytes);
System.out.println("Update saved: " + updatePacked);
unpack(updatePacked, updateFile);
System.out.println("Update unpacked: " + updateFile);
updateFile.setLastModified(mod1);
updatePacked.delete();
// Let the user know
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JOptionPane
.showMessageDialog(null,
"A new update is available. Restart application to apply");
}
});
}
/**
* Returns the Main jar file.
*/
private static File getAppFile(String aName) {
return new File(getAppDir(), aName);
}
/**
* Returns the Main jar file.
*/
private static File getAppDir() {
return getAppDataDir(AppDirName, true);
}
/**
*
* Utility Methods for AppLoader.
*
*/
/**
* Copies a file from one location to another.
*/
public static File copyFile(File aSource, File aDest) throws IOException {
// Get input stream, output file and output stream
FileInputStream fis = new FileInputStream(aSource);
File out = aDest.isDirectory() ? new File(aDest, aSource.getName())
: aDest;
FileOutputStream fos = new FileOutputStream(out);
// Iterate over read/write until all bytes written
byte[] buf = new byte[8192];
for (int i = fis.read(buf); i != -1; i = fis.read(buf))
fos.write(buf, 0, i);
// Close in/out streams and return out file
fis.close();
fos.close();
return out;
}
/**
* Writes the given bytes (within the specified range) to the given file.
*/
public static void writeBytes(File aFile, byte theBytes[])
throws IOException {
if (theBytes == null) {
aFile.delete();
return;
}
FileOutputStream fileStream = new FileOutputStream(aFile);
fileStream.write(theBytes);
fileStream.close();
}
/**
* Unpacks the given file into the destination file.
*/
public static File unpack(File aFile, File aDestFile) throws IOException {
// Get dest file - if already unpacked, return
File destFile = getUnpackDestination(aFile, aDestFile);
if (destFile.exists() && destFile.lastModified() > aFile.lastModified())
return destFile;
// Create streams: FileInputStream -> GZIPInputStream -> JarOutputStream
// -> FileOutputStream
FileInputStream fileInput = new FileInputStream(aFile);
GZIPInputStream gzipInput = new GZIPInputStream(fileInput);
FileOutputStream fileOut = new FileOutputStream(destFile);
JarOutputStream jarOut = new JarOutputStream(fileOut);
// Unpack file
Pack200.newUnpacker().unpack(gzipInput, jarOut);
// Close streams
fileInput.close();
gzipInput.close();
jarOut.close();
fileOut.close();
// Return destination file
return destFile;
}
/**
* Returns the file that given packed file would be saved to using the
* unpack method.
*/
public static File getUnpackDestination(File aFile, File aDestFile) {
// Get dest file - if null, create from packed file minus .pack.gz
File destFile = aDestFile;
if (destFile == null)
destFile = new File(aFile.getPath().replace(".pack.gz", ""));
// If dest file is directory, change to file inside with packed file
// minus .pack.gz
else if (destFile.isDirectory())
destFile = new File(destFile, aFile.getName().replace(".pack.gz",
""));
// Return destination file
return destFile;
}
/**
* Returns the AppData or Application Support directory file.
*/
public static File getAppDataDir(String aName, boolean doCreate) {
// Get user home + AppDataDir (platform specific) + name (if provided)
String dir = System.getProperty("user.home");
if (isWindows)
dir += File.separator + "AppData" + File.separator + "Local";
else if (isMac)
dir += File.separator + "Library" + File.separator
+ "Application Support";
if (aName != null)
dir += File.separator + aName;
// Create file, actual directory (if requested) and return
File dfile = new File(dir);
if (doCreate && aName != null)
dfile.mkdirs();
return dfile;
}
/**
* Returns bytes for connection.
*/
public static byte[] getBytes(URLConnection aConnection) throws IOException {
InputStream stream = aConnection.getInputStream(); // Get stream for
// connection
byte bytes[] = getBytes(stream); // Get bytes for stream
stream.close(); // Close stream
return bytes; // Return bytes
}
/**
* Returns bytes for an input stream.
*/
public static byte[] getBytes(InputStream aStream) throws IOException {
ByteArrayOutputStream bs = new ByteArrayOutputStream();
byte chunk[] = new byte[8192];
for (int len = aStream.read(chunk, 0, 8192); len > 0; len = aStream
.read(chunk, 0, 8192))
bs.write(chunk, 0, len);
return bs.toByteArray();
}
// Whether Windows/Mac
static boolean isWindows = (System.getProperty("os.name")
.indexOf("Windows") >= 0);
static boolean isMac = (System.getProperty("os.name").indexOf("Mac OS X") >= 0);
}
你的问题是你的copyFile方法FileInputStream采用了错误的File对象