下面列出了java.net.URLConnection#getContentLength ( ) 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。
private static byte[] getBytes(URL url) throws IOException {
URLConnection uc = url.openConnection();
if (uc instanceof java.net.HttpURLConnection) {
java.net.HttpURLConnection huc = (java.net.HttpURLConnection) uc;
int code = huc.getResponseCode();
if (code >= java.net.HttpURLConnection.HTTP_BAD_REQUEST) {
throw new IOException("open HTTP connection failed.");
}
}
int len = uc.getContentLength();
InputStream in = new BufferedInputStream(uc.getInputStream());
byte[] b;
try {
b = IOUtils.readFully(in, len, true);
} finally {
in.close();
}
return b;
}
public static long getFileSize(URL url) {
URLConnection conn = null;
try {
conn = url.openConnection();
if (conn instanceof HttpURLConnection) {
((HttpURLConnection) conn).setRequestMethod("HEAD");
}
conn.getInputStream();
return conn.getContentLength();
} catch (IOException e) {
Log.e(TAG, "URL-FILE_SIZE ERROR: "+e.getMessage());
e.printStackTrace();
return 0;
} finally {
if (conn instanceof HttpURLConnection) {
((HttpURLConnection) conn).disconnect();
}
}
}
/**
* Returns file size, located at the specified url.
*
* @param url file location url
* @return file size
*/
public static int getFileSize ( @NotNull final URL url )
{
try
{
// Creating URLConnection
final URLConnection uc = ProxyManager.getURLConnection ( url );
// todo This size is limited to maximum of 2GB, should retrieve long instead
// Retrieving file size
return uc.getContentLength ();
}
catch ( final Exception e )
{
throw new UtilityException ( "Unable to retrieve file size for URL: " + url, e );
}
}
public static void main(String[] args) throws Exception {
URLConnection conn = B7050028.class.getResource("B7050028.class").openConnection();
int len = conn.getContentLength();
byte[] data = new byte[len];
InputStream is = conn.getInputStream();
is.read(data);
is.close();
conn.setDefaultUseCaches(false);
File jar = File.createTempFile("B7050028", ".jar");
jar.deleteOnExit();
OutputStream os = new FileOutputStream(jar);
ZipOutputStream zos = new ZipOutputStream(os);
ZipEntry ze = new ZipEntry("B7050028.class");
ze.setMethod(ZipEntry.STORED);
ze.setSize(len);
CRC32 crc = new CRC32();
crc.update(data);
ze.setCrc(crc.getValue());
zos.putNextEntry(ze);
zos.write(data, 0, len);
zos.closeEntry();
zos.finish();
zos.close();
os.close();
System.out.println(new URLClassLoader(new URL[] {new URL("jar:" + jar.toURI() + "!/")}, ClassLoader.getSystemClassLoader().getParent()).loadClass(B7050028.class.getName()));
}
private static byte[] getBytes(URL url) throws IOException {
URLConnection uc = url.openConnection();
if (uc instanceof java.net.HttpURLConnection) {
java.net.HttpURLConnection huc = (java.net.HttpURLConnection) uc;
int code = huc.getResponseCode();
if (code >= java.net.HttpURLConnection.HTTP_BAD_REQUEST) {
throw new IOException("open HTTP connection failed.");
}
}
int len = uc.getContentLength();
InputStream in = new BufferedInputStream(uc.getInputStream());
byte[] b;
try {
b = IOUtils.readFully(in, len, true);
} finally {
in.close();
}
return b;
}
public static void main(String[] args) throws Exception {
URLConnection conn = B7050028.class.getResource("B7050028.class").openConnection();
int len = conn.getContentLength();
byte[] data = new byte[len];
InputStream is = conn.getInputStream();
is.read(data);
is.close();
conn.setDefaultUseCaches(false);
File jar = File.createTempFile("B7050028", ".jar");
jar.deleteOnExit();
OutputStream os = new FileOutputStream(jar);
ZipOutputStream zos = new ZipOutputStream(os);
ZipEntry ze = new ZipEntry("B7050028.class");
ze.setMethod(ZipEntry.STORED);
ze.setSize(len);
CRC32 crc = new CRC32();
crc.update(data);
ze.setCrc(crc.getValue());
zos.putNextEntry(ze);
zos.write(data, 0, len);
zos.closeEntry();
zos.finish();
zos.close();
os.close();
System.out.println(new URLClassLoader(new URL[] {new URL("jar:" + jar.toURI() + "!/")}, ClassLoader.getSystemClassLoader().getParent()).loadClass(B7050028.class.getName()));
}
@Test
public void testContentLength() throws Exception {
File f = new File("test/webresources/war-url-connection.war");
String fileUrl = f.toURI().toURL().toString();
URL indexHtmlUrl = new URL("jar:war:" + fileUrl +
"*/WEB-INF/lib/test.jar!/META-INF/resources/index.html");
URLConnection urlConn = indexHtmlUrl.openConnection();
urlConn.connect();
int size = urlConn.getContentLength();
Assert.assertEquals(137, size);
}
public UrlWebResource(final URL url, final String path, final String contentType, final boolean cacheable) {
this.url = checkNotNull(url);
this.path = checkNotNull(path);
this.cacheable = cacheable;
// open connection to get details about the resource
try {
final URLConnection connection = this.url.openConnection();
try (final InputStream ignore = connection.getInputStream()) {
if (Strings.isNullOrEmpty(contentType)) {
this.contentType = connection.getContentType();
}
else {
this.contentType = contentType;
}
// support for legacy int and modern long content-length
long detectedSize = connection.getContentLengthLong();
if (detectedSize == -1) {
detectedSize = connection.getContentLength();
}
this.size = detectedSize;
this.lastModified = connection.getLastModified();
}
}
catch (IOException e) {
throw new IllegalArgumentException("Resource inaccessible: " + url, e);
}
}
public void updateJar() {
boolean success = true;
try {
if (checkVersionNumber()) // Check if version is the same
return; // and return false if it is.
URL url = new URL(Constants.UPDATE_JAR_URL);
// Open connection
URLConnection connection = url.openConnection();
connection.setConnectTimeout(3000);
connection.setReadTimeout(3000);
int size = connection.getContentLength();
int offset = 0;
byte[] data = new byte[size];
InputStream input = url.openStream();
int readSize;
while ((readSize = input.read(data, offset, size - offset)) != -1) {
offset += readSize;
}
if (offset != size) {
} else {
File file = new File("./" + Constants.JAR_FILENAME);
FileOutputStream output = new FileOutputStream(file);
output.write(data);
output.close();
}
} catch (Exception ignored) {
}
}
@Override
public long contentLength() throws IOException {
URL url = getURL();
if (ResourceUtils.isFileURL(url)) {
// Proceed with file system resolution
return getFile().length();
}
else {
// Try a URL connection content-length header
URLConnection con = url.openConnection();
customizeConnection(con);
return con.getContentLength();
}
}
@Override
public long contentLength() throws IOException {
URL url = getURL();
if (ResourceUtils2.isFileURL(url)) {
// Proceed with file system resolution
return getFile().length();
} else {
// Try a URL connection content-length header
URLConnection con = url.openConnection();
customizeConnection(con);
return con.getContentLength();
}
}
private void download(URL url, File outputFile) throws IOException {
if (outputFile.exists()) {
log.info("We found an existing file and rename it as *.backup.");
FileUtil.renameFile(outputFile, new File(outputFile.getAbsolutePath() + ".backup"));
}
URLConnection urlConnection = url.openConnection();
urlConnection.connect();
int fileSize = urlConnection.getContentLength();
copyInputStreamToFileNew(urlConnection.getInputStream(), outputFile, fileSize);
}
private void parsePlaylistM3u(String url) throws IOException
{
URL website = new URL(url);
URLConnection conn = website.openConnection();
int size = conn.getContentLength();
if (size > 256 * 1024)
throw new IllegalArgumentException("File suspiciously big");
try (InputStream is = conn.getInputStream())
{
InputStreamReader read = new InputStreamReader(is, Charset.defaultCharset());
BufferedReader reader = new BufferedReader(read);
String line;
while ((line = reader.readLine()) != null)
{
int comIdx = line.indexOf('#');
if (comIdx >= 0)
line = line.substring(0, comIdx);
line = line.trim();
if (!line.isEmpty())
getAll(line);
}
}
}
public boolean comparefileSize(String localfilename,String remoteurl){
long localfile = 0;
long remotefile = 0;
long lastmodifylocal = 0;
long lastmodifyremote = 0;
try{
if(localfilename != null && remoteurl != null){
File fl = ct.getFileStreamPath( localfilename );
if(fl.exists()){
localfile = fl.length();
lastmodifylocal = fl.lastModified();
}else{
localfile = 0;
return false;
}
URLConnection connect = null;
URL newUrl=new URL(remoteurl);
connect=newUrl.openConnection();
connect.setRequestProperty ("Content-type","application/x-www-form-urlencoded");
connect.connect();
remotefile = connect.getContentLength();
lastmodifyremote = connect.getLastModified();
Log.i("local file size",localfile+"");
Log.i("remote file size",remotefile + "");
Log.i("last modify local ",lastmodifylocal+"");
Log.i("last modify remote ",lastmodifyremote + "");
if(localfile == remotefile){
return true;
}else{
return false;
}
}else{
return false;
}
}catch(Exception e){
e.printStackTrace();
return false;
}
}
public final Object getContent(URLConnection urlc) throws IOException {
int l = urlc.getContentLength();
com.net.rtsp.Debug.println("### BODY CONTENT LENGTH = "+l);
if (l > 0) {
byte[] c = new byte[l];
urlc.getInputStream().read(c);
com.net.rtsp.Debug.println("### BODY CONTENT = \n"+new String(c)+"\n####");
if(urlc.getContentType().toLowerCase().equals(getContentType().toLowerCase()))
return getResponseContent(c);
}
return null;
}
/**
* Changes the splash screen image. The new image is loaded from the
* specified URL; GIF, JPEG and PNG image formats are supported.
* The method returns after the image has finished loading and the window
* has been updated.
* The splash screen window is resized according to the size of
* the image and is centered on the screen.
*
* @param imageURL the non-<code>null</code> URL for the new
* splash screen image
* @throws NullPointerException if {@code imageURL} is <code>null</code>
* @throws IOException if there was an error while loading the image
* @throws IllegalStateException if the splash screen has already been
* closed
*/
public void setImageURL(URL imageURL) throws NullPointerException, IOException, IllegalStateException {
checkVisible();
URLConnection connection = imageURL.openConnection();
connection.connect();
int length = connection.getContentLength();
java.io.InputStream stream = connection.getInputStream();
byte[] buf = new byte[length];
int off = 0;
while(true) {
// check for available data
int available = stream.available();
if (available <= 0) {
// no data available... well, let's try reading one byte
// we'll see what happens then
available = 1;
}
// check for enough room in buffer, realloc if needed
// the buffer always grows in size 2x minimum
if (off + available > length) {
length = off*2;
if (off + available > length) {
length = available+off;
}
byte[] oldBuf = buf;
buf = new byte[length];
System.arraycopy(oldBuf, 0, buf, 0, off);
}
// now read the data
int result = stream.read(buf, off, available);
if (result < 0) {
break;
}
off += result;
}
synchronized(SplashScreen.class) {
checkVisible();
if (!_setImageData(splashPtr, buf)) {
throw new IOException("Bad image format or i/o error when loading image");
}
this.imageURL = imageURL;
}
}
/**
* Changes the splash screen image. The new image is loaded from the
* specified URL; GIF, JPEG and PNG image formats are supported.
* The method returns after the image has finished loading and the window
* has been updated.
* The splash screen window is resized according to the size of
* the image and is centered on the screen.
*
* @param imageURL the non-<code>null</code> URL for the new
* splash screen image
* @throws NullPointerException if {@code imageURL} is <code>null</code>
* @throws IOException if there was an error while loading the image
* @throws IllegalStateException if the splash screen has already been
* closed
*/
public void setImageURL(URL imageURL) throws NullPointerException, IOException, IllegalStateException {
checkVisible();
URLConnection connection = imageURL.openConnection();
connection.connect();
int length = connection.getContentLength();
java.io.InputStream stream = connection.getInputStream();
byte[] buf = new byte[length];
int off = 0;
while(true) {
// check for available data
int available = stream.available();
if (available <= 0) {
// no data available... well, let's try reading one byte
// we'll see what happens then
available = 1;
}
// check for enough room in buffer, realloc if needed
// the buffer always grows in size 2x minimum
if (off + available > length) {
length = off*2;
if (off + available > length) {
length = available+off;
}
byte[] oldBuf = buf;
buf = new byte[length];
System.arraycopy(oldBuf, 0, buf, 0, off);
}
// now read the data
int result = stream.read(buf, off, available);
if (result < 0) {
break;
}
off += result;
}
synchronized(SplashScreen.class) {
checkVisible();
if (!_setImageData(splashPtr, buf)) {
throw new IOException("Bad image format or i/o error when loading image");
}
this.imageURL = imageURL;
}
}
public boolean updateJar() {
boolean success = true;
setStatus("Starting rscplus update...");
setProgress(0, 1);
try {
URL url = new URL("https://github.com/RSCPlus/rscplus/releases/download/Latest/rscplus.jar");
// Open connection
URLConnection connection = url.openConnection();
connection.setConnectTimeout(3000);
connection.setReadTimeout(3000);
int size = connection.getContentLength();
int offset = 0;
byte[] data = new byte[size];
InputStream input = url.openStream();
int readSize;
while ((readSize = input.read(data, offset, size - offset)) != -1) {
offset += readSize;
setStatus("Updating rscplus (" + (offset / 1024) + "KiB / " + (size / 1024) + "KiB)");
setProgress(offset, size);
}
if (offset != size) {
success = false;
} else {
// TODO: Get the jar filename in Settings.initDir
File file = new File(Settings.Dir.JAR + "/rscplus.jar");
FileOutputStream output = new FileOutputStream(file);
output.write(data);
output.close();
setStatus("rscplus update complete");
}
} catch (Exception e) {
success = false;
}
return success;
}
/**
* Run method, called in separate thread
*/
public void run()
{
InputStream in = null;
try
{
// System.out.println("TD Running thread to get: " + _url.toString());
// Set http user agent on connection
URLConnection conn = _url.openConnection();
conn.setRequestProperty("User-Agent", "GpsPrune v" + GpsPrune.VERSION_NUMBER);
in = conn.getInputStream();
int len = conn.getContentLength();
if (len > 0)
{
byte[] data = new byte[len];
int totalRead = 0;
while (totalRead < len)
{
int numRead = in.read(data, totalRead, len-totalRead);
totalRead += numRead;
}
Image tile = Toolkit.getDefaultToolkit().createImage(data);
in.close();
// Pass back to manager so it can be stored in its memory cache
_manager.notifyImageLoaded(tile, _layer, _x, _y, _zoom);
if (!CONNECTION_ACTIVE)
{
// We've just come back online, so forget which tiles gave 404 before
System.out.println("Deleting blocked urls, currently holds " + BLOCKED_URLS.size());
synchronized(this.getClass())
{
BLOCKED_URLS.clear();
}
CONNECTION_ACTIVE = true;
}
}
}
catch (IOException e)
{
System.err.println("IOE: " + e.getClass().getName() + " - " + e.getMessage());
synchronized(this.getClass())
{
BLOCKED_URLS.add(_url.toString());
}
try {in.close();} catch (Exception e2) {}
CONNECTION_ACTIVE = false; // lost connection?
}
LOADING_URLS.remove(_url.toString());
}
protected void sendSync(String content) throws IOException {
if (sent) {
return;
}
try {
URLConnection c;
synchronized (this) {
c = this.connection;
}
if (c == null) {
return;
}
sent = true;
initConnectionRequestHeader(c);
int istatus;
String istatusText;
InputStream err;
if (c instanceof HttpURLConnection) {
HttpURLConnection hc = (HttpURLConnection) c;
String method = this.requestMethod == null ? DEFAULT_REQUEST_METHOD : this.requestMethod;
method = method.toUpperCase();
hc.setRequestMethod(method);
if ("POST".equals(method) && content != null) {
hc.setDoOutput(true);
byte[] contentBytes = content.getBytes(postCharset);
hc.setFixedLengthStreamingMode(contentBytes.length);
OutputStream out = hc.getOutputStream();
try {
out.write(contentBytes);
} finally {
out.flush();
}
}
istatus = hc.getResponseCode();
istatusText = hc.getResponseMessage();
err = hc.getErrorStream();
} else {
istatus = 0;
istatusText = "";
err = null;
}
synchronized (this) {
this.responseHeaders = getConnectionResponseHeaders(c);
this.responseHeadersMap = c.getHeaderFields();
}
this.changeState(AjaxHttpRequest.STATE_LOADED, istatus, istatusText, null);
InputStream in = err == null ? c.getInputStream() : err;
int contentLength = c.getContentLength();
this.changeState(AjaxHttpRequest.STATE_INTERACTIVE, istatus, istatusText, null);
byte[] bytes = loadStream(in, contentLength == -1 ? 4096 : contentLength);
this.changeState(AjaxHttpRequest.STATE_COMPLETE, istatus, istatusText, bytes);
} finally {
synchronized (this) {
this.connection = null;
sent = false;
}
}
}