Load file content to List : Text File « 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();
      }
    }
    
}








11.80.Text File
11.80.1.Read the contents of a file and place them in a string object.
11.80.2.Dump a String to a text file with encoding.
11.80.3.Load a text file contents as a String.
11.80.4.Read and return the entire contents of the supplied File.
11.80.5.Read ByteArrayInputStream to String
11.80.6.Load File As Text
11.80.7.Load file line by line
11.80.8.Load file content to List
11.80.9.Read string from InputStream and Reader
11.80.10.Gets the content from a File as String Array List
11.80.11.Searches case sensitively in a file
11.80.12.ReadLines: read file to list of strings