filereader.java

java tutorial.sun公司官方出品。java入门书籍。最新版

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 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
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 *
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 *   - Redistributions in binary form must reproduce the above copyright
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 */ 

import java.io.*;

public class FileReader {

    public static void main(String[] args) {
	try {
	    long dataPosition = 0;
	    int data = 0;
            RandomAccessFile raf = new RandomAccessFile("datafile", "r");

	    //Get the position of the data to read.
	    dataPosition = raf.readLong();

	    //Go to that position.
	    raf.seek(dataPosition);

	    //Read the data.
	    data = raf.readInt();
	    raf.close();

	    //Tell the world.
	    System.out.println("The data is: " + data);

	} catch (FileNotFoundException e) {
	    System.err.println("This shouldn't happen: " + e);
	} catch (IOException e) {
	    System.err.println("Writing error: " + e);
	}
    }
}