Example usage for java.io RandomAccessFile RandomAccessFile

Introduction

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

Prototype

public RandomAccessFile(File file, String mode) throws FileNotFoundException

Source Link

Document

Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument.

Usage

From source file:Main.java

public static void WriteTxtFile(Context context, String strcontent) {

    String strContent = strcontent + "\n";
    try {//from  www  .j av a2 s  .com
        File file = new File(context.getCacheDir() + File.separator + "wanjia.txt");
        if (!file.exists()) {
            file.createNewFile();
        }
        RandomAccessFile raf = new RandomAccessFile(file, "rw");
        raf.seek(file.length());
        raf.write(strContent.getBytes());
        raf.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

From source file:Main.java

public static byte[] getAsBinary(String key) {
    RandomAccessFile RAFile = null;
    boolean removeFile = false;
    try {/*from  w ww .  j  ava2 s  . c  o m*/
        File file = new File(cacheDir, key);
        if (!file.exists())
            return null;
        RAFile = new RandomAccessFile(file, "r");
        byte[] byteArray = new byte[(int) RAFile.length()];
        RAFile.read(byteArray);
        return byteArray;
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    } finally {
        if (RAFile != null) {
            try {
                RAFile.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

From source file:Main.java

public static float getTotalRAM() {
    RandomAccessFile reader = null;
    String load = null;/*from  w w w . j ava2  s  . com*/
    DecimalFormat twoDecimalForm = new DecimalFormat("#.##");
    double totRam = 0;
    float lastValue = 0;
    try {
        reader = new RandomAccessFile("/proc/meminfo", "r");
        load = reader.readLine();

        // Get the Number value from the string
        Pattern p = Pattern.compile("(\\d+)");
        Matcher m = p.matcher(load);
        String value = "";
        while (m.find()) {
            value = m.group(1);
            // System.out.println("Ram : " + value);
        }
        reader.close();

        totRam = Double.parseDouble(value);
        // totRam = totRam / 1024;

        float mb = (float) (totRam / 1024.0f);
        float gb = (float) (totRam / 1048576.0f);
        float tb = (float) (totRam / 1073741824.0f);

        lastValue = gb;
    } catch (IOException ex) {
        ex.printStackTrace();
    } finally {
        // Streams.close(reader);
    }

    return lastValue;
}

From source file:Main.java

public static void append(String fileName, byte[] bytes) throws Exception {
    File f = new File(fileName);
    long fileLength = f.length();
    RandomAccessFile raf = new RandomAccessFile(f, "rw");
    raf.seek(fileLength);/*from  w ww .  j  a v  a  2 s  .  c o  m*/
    raf.write(bytes);
    raf.close();
}

From source file:Main.java

public static boolean saveApk(File apk, String savePath) {
    FileInputStream in = null;/*from  w  ww.  j a v a2s  .co m*/
    RandomAccessFile accessFile = null;
    try {
        in = new FileInputStream(apk);
        byte[] buf = new byte[1024 * 4];
        int len;
        File file = new File(savePath);
        accessFile = new RandomAccessFile(file, "rw");
        FileDescriptor fd = accessFile.getFD();
        while ((len = in.read(buf)) != -1) {
            accessFile.write(buf, 0, len);
        }
        fd.sync();
        accessFile.close();
        in.close();
        return true;
    } catch (Exception e) {
        e.printStackTrace();
        try {
            if (in != null) {
                in.close();
            }
            if (accessFile != null) {
                accessFile.close();
            }
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        return false;
    }
}

From source file:Main.java

public static byte[] readFromFile(String fileName, int offset, int len) {
    if (fileName == null) {
        return null;
    }//w w w.  ja  v  a2s  .  c  om

    File file = new File(fileName);
    if (!file.exists()) {
        //WLog.i(FileUtils.class, "readFromFile: file not found");
        return null;
    }

    if (len == -1) {
        len = (int) file.length();
    }

    if (offset < 0) {
        //WLog.e(FileUtils.class, "readFromFile invalid offset:" + offset);
        return null;
    }
    if (len <= 0) {
        //WLog.e(FileUtils.class, "readFromFile invalid len:" + len);
        return null;
    }
    if (offset + len > (int) file.length()) {
        //WLog.e(FileUtils.class, "readFromFile invalid file len:" + file.length());
        return null;
    }

    byte[] b = null;
    try {
        RandomAccessFile in = new RandomAccessFile(fileName, "r");
        b = new byte[len];
        in.seek(offset);
        in.readFully(b);
        in.close();

    } catch (Exception e) {
        // WLog.e(FileUtils.class, "readFromFile : errMsg = " + e.getMessage());
        e.printStackTrace();
    }
    return b;
}

From source file:Main.java

public static void initialWrite(String fileName) throws IOException {
    RandomAccessFile raf = new RandomAccessFile(fileName, "rw");
    raf.writeInt(0);//from   w w w.j  a v a 2 s  . co  m
    raf.writeUTF("Hello world!");
    raf.close();
}

From source file:Main.java

public static long truncateFile(String fileName, long size) throws FileNotFoundException, IOException {
    RandomAccessFile raf = new RandomAccessFile(fileName, "rw");

    if (raf.length() >= size) {
        FileChannel channel = raf.getChannel();
        channel.truncate(size);/*w  w  w  .  j  a v a 2 s .  com*/
        return size;
    }

    return raf.length();
}

From source file:Main.java

public static byte[] readFromFile(String fileName, int offset, int len) {
    if (fileName == null) {
        return null;
    }//from   ww w  .  ja v  a 2s  . c o  m

    File file = new File(fileName);
    if (!file.exists()) {
        Log.i(TAG, "readFromFile: file not found");
        return null;
    }

    if (len == -1) {
        len = (int) file.length();
    }

    Log.d(TAG, "readFromFile : offset = " + offset + " len = " + len + " offset + len = " + (offset + len));

    if (offset < 0) {
        Log.e(TAG, "readFromFile invalid offset:" + offset);
        return null;
    }
    if (len <= 0) {
        Log.e(TAG, "readFromFile invalid len:" + len);
        return null;
    }
    if (offset + len > (int) file.length()) {
        Log.e(TAG, "readFromFile invalid file len:" + file.length());
        return null;
    }

    byte[] b = null;
    try {
        RandomAccessFile in = new RandomAccessFile(fileName, "r");
        b = new byte[len];
        in.seek(offset);
        in.readFully(b);
        in.close();

    } catch (Exception e) {
        Log.e(TAG, "readFromFile : errMsg = " + e.getMessage());
        e.printStackTrace();
    }
    return b;
}

From source file:Main.java

public static byte[] readFromFile(String fileName, int offset, int len) {
    if (fileName == null) {
        return null;
    }/*from  w w w.j  a v  a2  s.c  o m*/

    File file = new File(fileName);
    if (!file.exists()) {
        Log.i(TAG, "readFromFile: file not found");
        return null;
    }

    if (len == -1) {
        len = (int) file.length();
    }

    Log.d(TAG, "readFromFile : offset = " + offset + " len = " + len + " offset + len = " + (offset + len));

    if (offset < 0) {
        Log.e(TAG, "readFromFile invalid offset:" + offset);
        return null;
    }
    if (len <= 0) {
        Log.e(TAG, "readFromFile invalid len:" + len);
        return null;
    }
    if (offset + len > (int) file.length()) {
        Log.e(TAG, "readFromFile invalid file len:" + file.length());
        return null;
    }

    byte[] b = null;
    try {
        RandomAccessFile in = new RandomAccessFile(fileName, "r");
        b = new byte[len]; //
        in.seek(offset);
        in.readFully(b);
        in.close();

    } catch (Exception e) {
        Log.e(TAG, "readFromFile : errMsg = " + e.getMessage());
        e.printStackTrace();
    }
    return b;
}