Example usage for java.io InputStream read

Introduction

In this page you can find the example usage for java.io InputStream read.

Prototype

public int read(byte b[], int off, int len) throws IOException 

Source Link

Document

Reads up to len bytes of data from the input stream into an array of bytes.

Usage

From source file:Main.java

public static void main(String[] args) throws Exception {

    byte[] buffer = new byte[5];

    InputStream is = new FileInputStream("C://test.txt");

    System.out.println("Characters printed:");

    // read stream data into buffer
    is.read(buffer, 2, 3);

    // for each byte in the buffer
    for (byte b : buffer) {
        char c = ' ';

        // convert byte to character
        if (b == 0)// if b is empty
            c = '-';
        else/*from ww w .  ja  v  a2  s  .co  m*/
            c = (char) b;// if b is read
        System.out.print(c);
    }
    is.close();
}

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From source file:MainClass.java

public static void main(String args[]) throws Exception {
    byte buff[] = new byte[1024];
    InetAddress addr = InetAddress.getByName("www.java2s.com");
    Socket s = new Socket(addr, 80);

    OutputStream output = s.getOutputStream();
    InputStream input = s.getInputStream();
    String GetCmd = "GET /index.html HTTP/1.0\r\n\r\n";
    GetCmd.getBytes(0, GetCmd.length(), buff, 0);
    output.write(buff);//from  w  w w .j  av  a2 s.  c  om
    input.read(buff, 0, buff.length);
    System.out.println(new String(buff, 0));

}

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From source file:Main.java

public static void main(String[] argv) throws Exception {
        Socket sock = new Socket("127.0.0.1", 123456);
        byte[] mybytearray = new byte[1024];
        InputStream is = sock.getInputStream();
        FileOutputStream fos = new FileOutputStream("s.pdf");
        BufferedOutputStream bos = new BufferedOutputStream(fos);
        int bytesRead = is.read(mybytearray, 0, mybytearray.length);
        bos.write(mybytearray, 0, bytesRead);
        bos.close();/* w w  w .j av a2s.  c om*/
        sock.close();
    }

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From source file:MainClass.java

public static void main(String args[]) throws Exception {

    URL u = new URL("http://www.java2s.com/binary.dat");
    URLConnection uc = u.openConnection();
    String contentType = uc.getContentType();
    int contentLength = uc.getContentLength();
    if (contentType.startsWith("text/") || contentLength == -1) {
        throw new IOException("This is not a binary file.");
    }/*w w w  .j  ava 2 s .  co  m*/
    InputStream raw = uc.getInputStream();
    InputStream in = new BufferedInputStream(raw);
    byte[] data = new byte[contentLength];
    int bytesRead = 0;
    int offset = 0;
    while (offset < contentLength) {
        bytesRead = in.read(data, offset, data.length - offset);
        if (bytesRead == -1)
            break;
        offset += bytesRead;
    }
    in.close();

    if (offset != contentLength) {
        throw new IOException("Only read " + offset + " bytes; Expected " + contentLength + " bytes");
    }

    String filename = u.getFile().substring(filename.lastIndexOf('/') + 1);
    FileOutputStream out = new FileOutputStream(filename);
    out.write(data);
    out.flush();
    out.close();
}

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From source file:SignatureTest.java

public static void main(String[] args) {
    try {/*from   www  .j ava  2s .  c  o m*/
        if (args[0].equals("-genkeypair")) {
            KeyPairGenerator pairgen = KeyPairGenerator.getInstance("DSA");
            SecureRandom random = new SecureRandom();
            pairgen.initialize(KEYSIZE, random);
            KeyPair keyPair = pairgen.generateKeyPair();
            ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(args[1]));
            out.writeObject(keyPair.getPublic());
            out.close();
            out = new ObjectOutputStream(new FileOutputStream(args[2]));
            out.writeObject(keyPair.getPrivate());
            out.close();
        } else if (args[0].equals("-sign")) {
            ObjectInputStream keyIn = new ObjectInputStream(new FileInputStream(args[3]));
            PrivateKey privkey = (PrivateKey) keyIn.readObject();
            keyIn.close();

            Signature signalg = Signature.getInstance("DSA");
            signalg.initSign(privkey);

            File infile = new File(args[1]);
            InputStream in = new FileInputStream(infile);
            int length = (int) infile.length();
            byte[] message = new byte[length];
            in.read(message, 0, length);
            in.close();

            signalg.update(message);
            byte[] signature = signalg.sign();

            DataOutputStream out = new DataOutputStream(new FileOutputStream(args[2]));
            int signlength = signature.length;
            out.writeInt(signlength);
            out.write(signature, 0, signlength);
            out.write(message, 0, length);
            out.close();
        } else if (args[0].equals("-verify")) {
            ObjectInputStream keyIn = new ObjectInputStream(new FileInputStream(args[2]));
            PublicKey pubkey = (PublicKey) keyIn.readObject();
            keyIn.close();

            Signature verifyalg = Signature.getInstance("DSA");
            verifyalg.initVerify(pubkey);

            File infile = new File(args[1]);
            DataInputStream in = new DataInputStream(new FileInputStream(infile));
            int signlength = in.readInt();
            byte[] signature = new byte[signlength];
            in.read(signature, 0, signlength);

            int length = (int) infile.length() - signlength - 4;
            byte[] message = new byte[length];
            in.read(message, 0, length);
            in.close();

            verifyalg.update(message);
            if (!verifyalg.verify(signature))
                System.out.print("not ");
            System.out.println("verified");
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

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From source file:Main.java

public static void main(String[] argv) throws Exception {
    File file = new File("c:\\a.bat");
    InputStream is = new FileInputStream(file);

    long length = file.length();
    if (length > Integer.MAX_VALUE) {
        System.out.println("File is too large");
    }/* ww  w.  j  av  a 2 s. c o  m*/

    byte[] bytes = new byte[(int) length];

    int offset = 0;
    int numRead = 0;
    while (numRead >= 0) {
        numRead = is.read(bytes, offset, bytes.length - offset);
        offset += numRead;
    }

    if (offset < bytes.length) {
        throw new IOException("Could not completely read file " + file.getName());
    }
    is.close();
    System.out.println(new String(bytes));
}

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From source file:ImportKey.java

/**
 * <p>//from ww  w.  j  a va 2  s.  com
 * Takes two file names for a key and the certificate for the key, and
 * imports those into a keystore. Optionally it takes an alias for the key.
 * <p>
 * The first argument is the filename for the key. The key should be in
 * PKCS8-format.
 * <p>
 * The second argument is the filename for the certificate for the key.
 * <p>
 * If a third argument is given it is used as the alias. If missing, the key
 * is imported with the alias importkey
 * <p>
 * The name of the keystore file can be controlled by setting the keystore
 * property (java -Dkeystore=mykeystore). If no name is given, the file is
 * named <code>keystore.ImportKey</code> and placed in your home directory.
 * 
 * @param args
 *            [0] Name of the key file, [1] Name of the certificate file [2]
 *            Alias for the key.
 **/
public static void main(String args[]) {

    // change this if you want another password by default
    String keypass = "password";

    // change this if you want another alias by default
    String defaultalias = "tomcat";

    // change this if you want another keystorefile by default
    String keystorename = null;

    // parsing command line input
    String keyfile = "";
    String certfile = "";
    if (args.length < 3 || args.length > 4) {
        System.out.println("Usage: java comu.ImportKey keystore keyfile certfile [alias]");
        System.exit(0);
    } else {
        keystorename = args[0];
        keyfile = args[1];
        certfile = args[2];
        if (args.length > 3)
            defaultalias = args[3];
    }

    try {
        // initializing and clearing keystore
        KeyStore ks = KeyStore.getInstance("JKS", "SUN");
        ks.load(null, keypass.toCharArray());
        System.out.println("Using keystore-file : " + keystorename);
        ks.store(new FileOutputStream(keystorename), keypass.toCharArray());
        ks.load(new FileInputStream(keystorename), keypass.toCharArray());

        // loading Key
        InputStream fl = fullStream(keyfile);
        byte[] key = new byte[fl.available()];
        KeyFactory kf = KeyFactory.getInstance("RSA");
        fl.read(key, 0, fl.available());
        fl.close();
        PKCS8EncodedKeySpec keysp = new PKCS8EncodedKeySpec(key);
        PrivateKey ff = kf.generatePrivate(keysp);

        // loading CertificateChain
        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        InputStream certstream = fullStream(certfile);

        Collection c = cf.generateCertificates(certstream);
        Certificate[] certs = new Certificate[c.toArray().length];

        if (c.size() == 1) {
            certstream = fullStream(certfile);
            System.out.println("One certificate, no chain.");
            Certificate cert = cf.generateCertificate(certstream);
            certs[0] = cert;
        } else {
            System.out.println("Certificate chain length: " + c.size());
            certs = (Certificate[]) c.toArray(new Certificate[c.size()]);
        }

        // storing keystore
        ks.setKeyEntry(defaultalias, ff, keypass.toCharArray(), certs);
        System.out.println("Key and certificate stored.");
        System.out.println("Alias:" + defaultalias + "  Password:" + keypass);
        ks.store(new FileOutputStream(keystorename), keypass.toCharArray());
    } catch (Exception ex) {
        ex.printStackTrace();
    }
}

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From source file:RSATest.java

public static void main(String[] args) {
    try {// ww w .  jav a 2 s.  co  m
        if (args[0].equals("-genkey")) {
            KeyPairGenerator pairgen = KeyPairGenerator.getInstance("RSA");
            SecureRandom random = new SecureRandom();
            pairgen.initialize(KEYSIZE, random);
            KeyPair keyPair = pairgen.generateKeyPair();
            ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(args[1]));
            out.writeObject(keyPair.getPublic());
            out.close();
            out = new ObjectOutputStream(new FileOutputStream(args[2]));
            out.writeObject(keyPair.getPrivate());
            out.close();
        } else if (args[0].equals("-encrypt")) {
            KeyGenerator keygen = KeyGenerator.getInstance("AES");
            SecureRandom random = new SecureRandom();
            keygen.init(random);
            SecretKey key = keygen.generateKey();

            // wrap with RSA public key
            ObjectInputStream keyIn = new ObjectInputStream(new FileInputStream(args[3]));
            Key publicKey = (Key) keyIn.readObject();
            keyIn.close();

            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.WRAP_MODE, publicKey);
            byte[] wrappedKey = cipher.wrap(key);
            DataOutputStream out = new DataOutputStream(new FileOutputStream(args[2]));
            out.writeInt(wrappedKey.length);
            out.write(wrappedKey);

            InputStream in = new FileInputStream(args[1]);
            cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            crypt(in, out, cipher);
            in.close();
            out.close();
        } else {
            DataInputStream in = new DataInputStream(new FileInputStream(args[1]));
            int length = in.readInt();
            byte[] wrappedKey = new byte[length];
            in.read(wrappedKey, 0, length);

            // unwrap with RSA private key
            ObjectInputStream keyIn = new ObjectInputStream(new FileInputStream(args[3]));
            Key privateKey = (Key) keyIn.readObject();
            keyIn.close();

            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.UNWRAP_MODE, privateKey);
            Key key = cipher.unwrap(wrappedKey, "AES", Cipher.SECRET_KEY);

            OutputStream out = new FileOutputStream(args[2]);
            cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.DECRYPT_MODE, key);

            crypt(in, out, cipher);
            in.close();
            out.close();
        }
    } catch (IOException e) {
        e.printStackTrace();
    } catch (GeneralSecurityException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }
}

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From source file:Main.java

private static void readIntoBuffer(final InputStream is, final int length) throws IOException {
    int read = is.read(BUFFER, 0, length);
    if (read != length) {
        throw new EOFException();
    }/*w w  w. j ava 2  s.  c om*/
}

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From source file:Main.java

private static boolean read(InputStream is, byte[] buf, int length) {
    try {//from   w  w w  .  j ava  2s . c o m
        return is.read(buf, 0, length) == length;
    } catch (IOException ex) {
        return false;
    }
}

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