Load File as byte array : Byte Array « File « Java Tutorial






/*
    GNU LESSER GENERAL PUBLIC LICENSE
    Copyright (C) 2006 The Lobo Project

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Contact info: lobochief@users.sourceforge.net
*/
/*
 * Created on Mar 19, 2005
 */

import java.io.*;

/**
 * @author J. H. S.
 */
public class IORoutines {
  public static final byte[] LINE_BREAK_BYTES = { (byte) 13, (byte) 10 }; 
  
  public static String loadAsText(InputStream in, String encoding) throws IOException {
    return loadAsText(in, encoding, 4096);
  }
  
  public static String loadAsText(InputStream in, String encoding, int bufferSize) throws IOException {
    InputStreamReader reader = new InputStreamReader(in, encoding);
      char[] buffer = new char[bufferSize];
      int offset = 0;
      for(;;) {
        int remain = buffer.length - offset;
        if(remain <= 0) {
          char[] newBuffer = new char[buffer.length * 2];
          System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
          buffer = newBuffer;
          remain = buffer.length - offset;
        }
          int numRead = reader.read(buffer, offset, remain);
          if(numRead == -1) {
            break;
          }
        offset += numRead;
      }
      return new String(buffer, 0, offset);
  }
  
    public static byte[] load(File file) throws IOException {
        long fileLength = file.length();
        if(fileLength > Integer.MAX_VALUE) {
            throw new IOException("File '" + file.getName() + "' too big");
        }
        InputStream in = new FileInputStream(file);
        try {
          return loadExact(in, (int) fileLength);
        } finally {
            in.close();
        }
    }
    
    public static byte[] load(InputStream in) throws IOException {
        return load(in, 4096);
    }
    public static byte[] load(InputStream in, int initialBufferSize) throws IOException {
      if(initialBufferSize == 0) {
        initialBufferSize = 1;
      }
      byte[] buffer = new byte[initialBufferSize];
      int offset = 0;
      for(;;) {
        int remain = buffer.length - offset;
        if(remain <= 0) {
          int newSize = buffer.length * 2;
          byte[] newBuffer = new byte[newSize];
          System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
          buffer = newBuffer;
          remain = buffer.length - offset;
        }
          int numRead = in.read(buffer, offset, remain);
          if(numRead == -1) {
            break;
          }
        offset += numRead;
      }
      if(offset < buffer.length) {
        byte[] newBuffer = new byte[offset];
        System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
        buffer = newBuffer;
      }
      return buffer;
    }
    
    public static byte[] loadExact(InputStream in, int length) throws IOException {
      byte[] buffer = new byte[length];
      int offset = 0;
      for(;;) {
        int remain = length - offset;
        if(remain <= 0) {
          break;
        }
        int numRead = in.read(buffer, offset, remain);
        if(numRead == -1) {
          throw new IOException("Reached EOF, read " + offset + " expecting " + length);
        }
      offset += numRead;
      }
      return buffer;
    }

    public static boolean equalContent(File file, byte[] content) throws IOException {
      long length = file.length();
      if(length > Integer.MAX_VALUE) {
        throw new IOException("File '" + file + "' too big");
      }
      InputStream in = new FileInputStream(file);
      try {
        byte[] fileContent = loadExact(in, (int) length);
        return java.util.Arrays.equals(content, fileContent);
      } finally {
        in.close();
      }
    }
    
    public static void save(File file, byte[] content) throws IOException {
      FileOutputStream out = new FileOutputStream(file);
      try {
        out.write(content);
      } finally {
        out.close();
      }
    }
    
    /**
     * Reads line without buffering.
     */
    public static String readLine(InputStream in) throws IOException {
      int b;
      StringBuffer sb = null;
      OUTER:
      while((b = in.read()) != -1) {
        if(sb == null) {
          sb = new StringBuffer();
        }
        switch(b) {
          case (byte) '\n':
            break OUTER;
          case (byte) '\r':
            break;
          default:
            sb.append((char) b);
            break;
        }
      }
      return sb == null ? null : sb.toString();
    }
    
    public static void touch(File file) {
      file.setLastModified(System.currentTimeMillis());
    }
    
    public static void saveStrings(File file, java.util.Collection list) throws IOException {
      BufferedOutputStream bout = new BufferedOutputStream(new FileOutputStream(file));
      try {
        PrintWriter writer = new PrintWriter(bout);
        java.util.Iterator i = list.iterator();
        while(i.hasNext()) {
          String text = (String) i.next();
          writer.println(text);
        }
        writer.flush();
      } finally {
        bout.close();
      }
    }
    
    public static java.util.List loadStrings(File file) throws IOException {
      java.util.List list = new java.util.LinkedList();
      InputStream in = new FileInputStream(file);
      try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String line;
        while((line = reader.readLine()) != null) {
          list.add(line);
        }
        return list;
      } finally {
        in.close();
      }
    }
    
}








11.77.Byte Array
11.77.1.Load file to byte array
11.77.2.Load File as byte array
11.77.3.Convert Byte array to Int
11.77.4.Gets an array of bytes corresponding to the given object
11.77.5.Convert byte array to string
11.77.6.An optimized reader for reading byte streams that only contain 7-bit ASCII characters.
11.77.7.Convert a base16 string into a byte array.
11.77.8.Convert a byte array to a human-readable String for debugging purposes.
11.77.9.Convert the bytes within the specified range of the given byte array into a String
11.77.10.Convert the bytes within the specified range of the given byte array into a signed integer in the given radix
11.77.11.Converts a byte array into a hexadecimal string
11.77.12.Converts a byte array into hexadecimal characters which are written as ASCII to the given output stream.
11.77.13.Decode hex string to a byte array
11.77.14.Encode a byte array to hex string
11.77.15.Get bytes from InputStream
11.77.16.Read and return the entire contents of the supplied file.
11.77.17.Reads bytes available from one InputStream and returns these bytes in a byte array.
11.77.18.Return the specified class. Checks the ThreadContext classloader first, then uses the System classloader.
11.77.19.Translates between byte arrays and strings of "0"s and "1"s.