List of usage examples for java.nio ByteBuffer clear
public final Buffer clear()
From source file:org.apache.hadoop.hdfs.hoss.db.FileStreamStore.java
public static void main(String[] args) { final int BUFFER_LEN = 4096;//65536 final int TOTAL = 10000000; FileStreamStore fss = new FileStreamStore("./data/stream", BUFFER_LEN); final ByteBuffer buf = ByteBuffer.allocate(BUFFER_LEN); final long[] offset = new long[TOTAL]; fss.delete();// ww w. j a v a 2 s .c o m fss.open(); // Parameters fss.setFlushOnWrite(false); fss.setSyncOnFlush(false); fss.setAlignBlocks(true); long start = System.currentTimeMillis(); for (int i = 0; i < TOTAL; i++) { buf.clear(); StringSerializer.fromStringToBuffer(buf, "hehe" + i); buf.flip(); offset[i] = fss.write(buf); } fss.sync(); //System.out.println(ArrayUtils.toString(offset)); System.out.println("write time: " + (System.currentTimeMillis() - start) / 1000); start = System.currentTimeMillis(); long newOffset = 0; for (int i = 0; i < TOTAL; i++) { buf.clear(); newOffset = fss.read(newOffset, buf); if (newOffset < 0) { System.out.println("Error trying read offset " + i + " size=" + fss.size()); break; } StringSerializer.fromBufferToString(buf); //System.out.print(hehe + "\t"); } System.out.println("read time: " + (System.currentTimeMillis() - start) / 1000); }
From source file:MainClass.java
public static void main(String[] args) { String[] phrases = { "A", "B 1", "C 1.3" }; String dirname = "C:/test"; String filename = "Phrases.txt"; File dir = new File(dirname); File aFile = new File(dir, filename); FileOutputStream outputFile = null; try {// w ww .j a v a2 s. co m outputFile = new FileOutputStream(aFile, true); } catch (FileNotFoundException e) { e.printStackTrace(System.err); } FileChannel outChannel = outputFile.getChannel(); ByteBuffer buf = ByteBuffer.allocate(1024); System.out.println(buf.position()); System.out.println(buf.limit()); System.out.println(buf.capacity()); CharBuffer charBuf = buf.asCharBuffer(); System.out.println(charBuf.position()); System.out.println(charBuf.limit()); System.out.println(charBuf.capacity()); Formatter formatter = new Formatter(charBuf); int number = 0; for (String phrase : phrases) { formatter.format("%n %s", ++number, phrase); System.out.println(charBuf.position()); System.out.println(charBuf.limit()); System.out.println(charBuf.capacity()); charBuf.flip(); System.out.println(charBuf.position()); System.out.println(charBuf.limit()); System.out.println(charBuf.length()); buf.limit(2 * charBuf.length()); // Set byte buffer limit System.out.println(buf.position()); System.out.println(buf.limit()); System.out.println(buf.remaining()); try { outChannel.write(buf); buf.clear(); charBuf.clear(); } catch (IOException e) { e.printStackTrace(System.err); } } try { outputFile.close(); } catch (IOException e) { e.printStackTrace(System.err); } }
From source file:MainClass.java
public static void main(String[] args) throws IOException { Charset charset = Charset.forName("ISO-8859-1"); CharsetEncoder encoder = charset.newEncoder(); CharsetDecoder decoder = charset.newDecoder(); ByteBuffer buffer = ByteBuffer.allocate(512); Selector selector = Selector.open(); ServerSocketChannel server = ServerSocketChannel.open(); server.socket().bind(new java.net.InetSocketAddress(8000)); server.configureBlocking(false);//from www .j a va 2s .co m SelectionKey serverkey = server.register(selector, SelectionKey.OP_ACCEPT); for (;;) { selector.select(); Set keys = selector.selectedKeys(); for (Iterator i = keys.iterator(); i.hasNext();) { SelectionKey key = (SelectionKey) i.next(); i.remove(); if (key == serverkey) { if (key.isAcceptable()) { SocketChannel client = server.accept(); client.configureBlocking(false); SelectionKey clientkey = client.register(selector, SelectionKey.OP_READ); clientkey.attach(new Integer(0)); } } else { SocketChannel client = (SocketChannel) key.channel(); if (!key.isReadable()) continue; int bytesread = client.read(buffer); if (bytesread == -1) { key.cancel(); client.close(); continue; } buffer.flip(); String request = decoder.decode(buffer).toString(); buffer.clear(); if (request.trim().equals("quit")) { client.write(encoder.encode(CharBuffer.wrap("Bye."))); key.cancel(); client.close(); } else { int num = ((Integer) key.attachment()).intValue(); String response = num + ": " + request.toUpperCase(); client.write(encoder.encode(CharBuffer.wrap(response))); key.attach(new Integer(num + 1)); } } } } }
From source file:GetWebPageApp.java
public static void main(String args[]) throws Exception { String resource, host, file;//from w w w. ja va 2s . co m int slashPos; resource = "www.java2s.com/index.htm"; // skip HTTP:// slashPos = resource.indexOf('/'); // find host/file separator if (slashPos < 0) { resource = resource + "/"; slashPos = resource.indexOf('/'); } file = resource.substring(slashPos); // isolate host and file parts host = resource.substring(0, slashPos); System.out.println("Host to contact: '" + host + "'"); System.out.println("File to fetch : '" + file + "'"); SocketChannel channel = null; try { Charset charset = Charset.forName("ISO-8859-1"); CharsetDecoder decoder = charset.newDecoder(); CharsetEncoder encoder = charset.newEncoder(); ByteBuffer buffer = ByteBuffer.allocateDirect(1024); CharBuffer charBuffer = CharBuffer.allocate(1024); InetSocketAddress socketAddress = new InetSocketAddress(host, 80); channel = SocketChannel.open(); channel.configureBlocking(false); channel.connect(socketAddress); selector = Selector.open(); channel.register(selector, SelectionKey.OP_CONNECT | SelectionKey.OP_READ); while (selector.select(500) > 0) { Set readyKeys = selector.selectedKeys(); try { Iterator readyItor = readyKeys.iterator(); while (readyItor.hasNext()) { SelectionKey key = (SelectionKey) readyItor.next(); readyItor.remove(); SocketChannel keyChannel = (SocketChannel) key.channel(); if (key.isConnectable()) { if (keyChannel.isConnectionPending()) { keyChannel.finishConnect(); } String request = "GET " + file + " \r\n\r\n"; keyChannel.write(encoder.encode(CharBuffer.wrap(request))); } else if (key.isReadable()) { keyChannel.read(buffer); buffer.flip(); decoder.decode(buffer, charBuffer, false); charBuffer.flip(); System.out.print(charBuffer); buffer.clear(); charBuffer.clear(); } else { System.err.println("Unknown key"); } } } catch (ConcurrentModificationException e) { } } } catch (UnknownHostException e) { System.err.println(e); } catch (IOException e) { System.err.println(e); } finally { if (channel != null) { try { channel.close(); } catch (IOException ignored) { } } } System.out.println("\nDone."); }
From source file:HttpGet.java
public static void main(String[] args) { SocketChannel server = null; // Channel for reading from server FileOutputStream outputStream = null; // Stream to destination file WritableByteChannel destination; // Channel to write to it try { // Exception handling and channel closing code follows this block // Parse the URL. Note we use the new java.net.URI, not URL here. URI uri = new URI(args[0]); // Now query and verify the various parts of the URI String scheme = uri.getScheme(); if (scheme == null || !scheme.equals("http")) throw new IllegalArgumentException("Must use 'http:' protocol"); String hostname = uri.getHost(); int port = uri.getPort(); if (port == -1) port = 80; // Use default port if none specified String path = uri.getRawPath(); if (path == null || path.length() == 0) path = "/"; String query = uri.getRawQuery(); query = (query == null) ? "" : '?' + query; // Combine the hostname and port into a single address object. // java.net.SocketAddress and InetSocketAddress are new in Java 1.4 SocketAddress serverAddress = new InetSocketAddress(hostname, port); // Open a SocketChannel to the server server = SocketChannel.open(serverAddress); // Put together the HTTP request we'll send to the server. String request = "GET " + path + query + " HTTP/1.1\r\n" + // The request "Host: " + hostname + "\r\n" + // Required in HTTP 1.1 "Connection: close\r\n" + // Don't keep connection open "User-Agent: " + HttpGet.class.getName() + "\r\n" + "\r\n"; // Blank // line // indicates // end of // request // headers // Now wrap a CharBuffer around that request string CharBuffer requestChars = CharBuffer.wrap(request); // Get a Charset object to encode the char buffer into bytes Charset charset = Charset.forName("ISO-8859-1"); // Use the charset to encode the request into a byte buffer ByteBuffer requestBytes = charset.encode(requestChars); // Finally, we can send this HTTP request to the server. server.write(requestBytes);//ww w .j a v a 2 s . co m // Set up an output channel to send the output to. if (args.length > 1) { // Use a specified filename outputStream = new FileOutputStream(args[1]); destination = outputStream.getChannel(); } else // Or wrap a channel around standard out destination = Channels.newChannel(System.out); // Allocate a 32 Kilobyte byte buffer for reading the response. // Hopefully we'll get a low-level "direct" buffer ByteBuffer data = ByteBuffer.allocateDirect(32 * 1024); // Have we discarded the HTTP response headers yet? boolean skippedHeaders = false; // The code sent by the server int responseCode = -1; // Now loop, reading data from the server channel and writing it // to the destination channel until the server indicates that it // has no more data. while (server.read(data) != -1) { // Read data, and check for end data.flip(); // Prepare to extract data from buffer // All HTTP reponses begin with a set of HTTP headers, which // we need to discard. The headers end with the string // "\r\n\r\n", or the bytes 13,10,13,10. If we haven't already // skipped them then do so now. if (!skippedHeaders) { // First, though, read the HTTP response code. // Assume that we get the complete first line of the // response when the first read() call returns. Assume also // that the first 9 bytes are the ASCII characters // "HTTP/1.1 ", and that the response code is the ASCII // characters in the following three bytes. if (responseCode == -1) { responseCode = 100 * (data.get(9) - '0') + 10 * (data.get(10) - '0') + 1 * (data.get(11) - '0'); // If there was an error, report it and quit // Note that we do not handle redirect responses. if (responseCode < 200 || responseCode >= 300) { System.err.println("HTTP Error: " + responseCode); System.exit(1); } } // Now skip the rest of the headers. try { for (;;) { if ((data.get() == 13) && (data.get() == 10) && (data.get() == 13) && (data.get() == 10)) { skippedHeaders = true; break; } } } catch (BufferUnderflowException e) { // If we arrive here, it means we reached the end of // the buffer and didn't find the end of the headers. // There is a chance that the last 1, 2, or 3 bytes in // the buffer were the beginning of the \r\n\r\n // sequence, so back up a bit. data.position(data.position() - 3); // Now discard the headers we have read data.compact(); // And go read more data from the server. continue; } } // Write the data out; drain the buffer fully. while (data.hasRemaining()) destination.write(data); // Now that the buffer is drained, put it into fill mode // in preparation for reading more data into it. data.clear(); // data.compact() also works here } } catch (Exception e) { // Report any errors that arise System.err.println(e); System.err.println("Usage: java HttpGet <URL> [<filename>]"); } finally { // Close the channels and output file stream, if needed try { if (server != null && server.isOpen()) server.close(); if (outputStream != null) outputStream.close(); } catch (IOException e) { } } }
From source file:PrintServiceWebInterface.java
public static void main(String[] args) throws IOException { // Get the character encoders and decoders we'll need Charset charset = Charset.forName("ISO-8859-1"); CharsetEncoder encoder = charset.newEncoder(); // The HTTP headers we send back to the client are fixed String headers = "HTTP/1.1 200 OK\r\n" + "Content-type: text/html\r\n" + "Connection: close\r\n" + "\r\n"; // We'll use two buffers in our response. One holds the fixed // headers, and the other holds the variable body of the response. ByteBuffer[] buffers = new ByteBuffer[2]; buffers[0] = encoder.encode(CharBuffer.wrap(headers)); ByteBuffer body = ByteBuffer.allocateDirect(16 * 1024); buffers[1] = body;// www.ja va 2 s . c om // Find all available PrintService objects to describe PrintService[] services = PrintServiceLookup.lookupPrintServices(null, null); // All of the channels we use in this code will be in non-blocking // mode. So we create a Selector object that will block while // monitoring all of the channels and will only stop blocking when // one or more of the channels is ready for I/O of some sort. Selector selector = Selector.open(); // Create a new ServerSocketChannel, and bind it to port 8000. // Note that we have to do this using the underlying ServerSocket. ServerSocketChannel server = ServerSocketChannel.open(); server.socket().bind(new java.net.InetSocketAddress(8000)); // Put the ServerSocketChannel into non-blocking mode server.configureBlocking(false); // Now register the channel with the Selector. The SelectionKey // represents the registration of this channel with this Selector. SelectionKey serverkey = server.register(selector, SelectionKey.OP_ACCEPT); for (;;) { // The main server loop. The server runs forever. // This call blocks until there is activity on one of the // registered channels. This is the key method in non-blocking I/O. selector.select(); // Get a java.util.Set containing the SelectionKey objects for // all channels that are ready for I/O. Set keys = selector.selectedKeys(); // Use a java.util.Iterator to loop through the selected keys for (Iterator i = keys.iterator(); i.hasNext();) { // Get the next SelectionKey in the set, and then remove it // from the set. It must be removed explicitly, or it will // be returned again by the next call to select(). SelectionKey key = (SelectionKey) i.next(); i.remove(); // Check whether this key is the SelectionKey we got when // we registered the ServerSocketChannel. if (key == serverkey) { // Activity on the ServerSocketChannel means a client // is trying to connect to the server. if (key.isAcceptable()) { // Accept the client connection, and obtain a // SocketChannel to communicate with the client. SocketChannel client = server.accept(); // Make sure we actually got a connection if (client == null) continue; // Put the client channel in non-blocking mode. client.configureBlocking(false); // Now register the client channel with the Selector, // specifying that we'd like to know when there is // data ready to read on the channel. SelectionKey clientkey = client.register(selector, SelectionKey.OP_READ); } } else { // If the key we got from the Set of keys is not the // ServerSocketChannel key, then it must be a key // representing one of the client connections. // Get the channel from the key. SocketChannel client = (SocketChannel) key.channel(); // If we got here, it should mean that there is data to // be read from the channel, but we double-check here. if (!key.isReadable()) continue; // Now read bytes from the client. We assume that // we get all the client's bytes in one read operation client.read(body); // The data we read should be some kind of HTTP GET // request. We don't bother checking it however since // there is only one page of data we know how to return. body.clear(); // Build an HTML document as our reponse. // The body of the document contains PrintService details StringBuffer response = new StringBuffer(); response.append( "<html><head><title>Printer Status</title></head>" + "<body><h1>Printer Status</h1>"); for (int s = 0; s < services.length; s++) { PrintService service = services[s]; response.append("<h2>").append(service.getName()).append("</h2><table>"); Attribute[] attrs = service.getAttributes().toArray(); for (int a = 0; a < attrs.length; a++) { Attribute attr = attrs[a]; response.append("<tr><td>").append(attr.getName()).append("</td><td>").append(attr) .append("</tr>"); } response.append("</table>"); } response.append("</body></html>\r\n"); // Encode the response into the body ByteBuffer encoder.reset(); encoder.encode(CharBuffer.wrap(response), body, true); encoder.flush(body); body.flip(); // Prepare the body buffer to be drained // While there are bytes left to write while (body.hasRemaining()) { // Write both header and body buffers client.write(buffers); } buffers[0].flip(); // Prepare header buffer for next write body.clear(); // Prepare body buffer for next read // Once we've sent our response, we have no more interest // in the client channel or its SelectionKey client.close(); // Close the channel. key.cancel(); // Tell Selector to stop monitoring it. } } } }
From source file:Main.java
public static ByteBuffer createByteBufferOnHeap(final int size) { final ByteBuffer buf = ByteBuffer.allocate(size).order(ByteOrder.nativeOrder()); buf.clear(); return buf;/*ww w. ja va 2 s . c o m*/ }
From source file:Main.java
public static byte[] getByteArray(final ByteBuffer buff) { if (buff == null) { return null; }//from w ww . j av a2 s. c o m buff.clear(); final byte[] inds = new byte[buff.limit()]; for (int x = 0; x < inds.length; x++) { inds[x] = buff.get(); } return inds; }
From source file:Main.java
public static ByteBuffer copy(ByteBuffer buffer) { final int length = buffer.limit() - buffer.position(); final ByteOrder o = buffer.order(); final ByteBuffer r = ByteBuffer.allocate(length); r.order(o);/* ww w .j av a 2 s . c o m*/ r.put(buffer); r.clear(); // Reset position and limit after the put() return r; }
From source file:Main.java
public static ByteBuffer createByteBuffer(final int size) { final ByteBuffer buf = ByteBuffer.allocateDirect(size).order(ByteOrder.nativeOrder()); buf.clear(); return buf;/* w w w . j a v a 2s. c om*/ }