Java InputStreamReader Read readFile(File file, String encoding)

Description

read File

License

Open Source License

Declaration

public static String readFile(File file, String encoding) throws IOException 

Method Source Code

//package com.java2s;
/**/*from  w w  w .j a v  a2  s . c  o m*/
 * ditaa - Diagrams Through Ascii Art
 * 
 * Copyright (C) 2004-2011 Efstathios Sideris
 *
 * ditaa 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 3 of
 * the License, or (at your option) any later version.
 *
 * ditaa 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 ditaa.  If not, see <http://www.gnu.org/licenses/>.
 *   
 */

import java.io.File;
import java.io.FileInputStream;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.LineNumberReader;

public class Main {
    public static String readFile(File file) throws IOException {
        return readFile(file, null);
    }

    public static String readFile(File file, String encoding) throws IOException {
        long length = file.length();

        if (length > Integer.MAX_VALUE) {
            // File is too large
            // TODO: we need some feedback for the case of the file being too large
        }

        return readFile(new FileInputStream(file), file.getName(), encoding, length);
    }

    public static String readFile(InputStream is, String name, String encoding) throws IOException {
        return readFile(is, name, encoding, -1);
    }

    public static String readFile(InputStream is, String name, String encoding, long length) throws IOException {

        if (length < 0) {
            LineNumberReader reader = new LineNumberReader(new InputStreamReader(is));
            StringBuilder builder = new StringBuilder();
            while (true) {
                String line = reader.readLine();
                if (line == null)
                    break;
                else
                    builder.append(line).append("\n");
            }
            return builder.toString();
        }

        else {
            // Create the byte array to hold the data
            byte[] bytes = new byte[(int) length];

            // Read in the bytes
            int offset = 0;
            int numRead = 0;
            while (offset < bytes.length && (numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) {
                offset += numRead;
            }

            // Ensure all the bytes have been read in
            if (offset < bytes.length) {
                throw new IOException("Could not completely read file " + name);
            }

            // Close the input stream and return bytes
            is.close();
            if (encoding == null) {
                return new String(bytes);
            } else {
                return new String(bytes, encoding);
            }
        }
    }
}

Related

1. readFile(File file)
2. readFile(File file)
3. readFile(File file)
4. readFile(File file)
5. readFile(File file, String default_encoding)
6. readFile(File file, String encoding)
7. readFile(File file, String encoding)
8. readFile(File file, String encoding)
9. readFile(File filename)