Java File Read via ByteBuffer readFile(String filename)

Description

read File

License

Apache License

Declaration

public static String readFile(String filename) 

Method Source Code

//package com.java2s;
/*//ww w  .java  2 s  .  c  o  m
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.BufferedReader;

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

import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;

import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;

public class Main {
    public static String readFile(InputStream inputStream) {
        if (inputStream != null) {
            byte[] bytes = getBytes(inputStream);
            return new String(bytes);
        }
        return null;
    }

    public static String readFile(String filename) {
        if (filename != null) {
            byte[] bytes = getBytes(filename);
            return new String(bytes);
        }
        return null;
    }

    public static String readFile(File file) {
        final StringBuilder contents = new StringBuilder();
        try {
            final BufferedReader input = new BufferedReader(new FileReader(file));
            try {
                String line = null;
                while ((line = input.readLine()) != null) {
                    contents.append(line);
                    contents.append(System.getProperty("line.separator"));
                }
            } finally {
                input.close();
            }
        } catch (IOException ex) {
            throw new RuntimeException(ex);
        }
        return contents.toString();
    }

    public static byte[] getBytes(File file) {
        try {
            return getBytes(new FileInputStream(file));
        } catch (IOException ex) {
            throw new RuntimeException(ex);
        }
    }

    public static byte[] getBytes(InputStream inputStream) {
        if (inputStream == null) {
            return null;
        }
        ByteArrayOutputStream output = null;
        try {
            ByteBuffer buffer = ByteBuffer.allocate(8192);
            ReadableByteChannel readChannel = Channels.newChannel(inputStream);
            output = new ByteArrayOutputStream(32 * 1024);
            WritableByteChannel writeChannel = Channels.newChannel(output);
            while ((readChannel.read(buffer)) > 0 || buffer.position() != 0) {
                buffer.flip();
                writeChannel.write(buffer);
                buffer.compact();
            }
            return output.toByteArray();
        } catch (IOException ex) {
            throw new RuntimeException(ex);
        } finally {
            if (output != null) {
                try {
                    output.close();
                    output = null;
                } catch (IOException ex) {
                }
            }
        }
    }

    public static byte[] getBytes(String filename) {
        filename = getJavaFileSystemPath(filename);
        File file = new File(filename);
        return getBytes(file);
    }

    public static String getJavaFileSystemPath(String path) {
        if (path == null) {
            return null;
        }
        path = path.replace('\\', '/');
        return path;
    }
}

Related

1. readFile(File file)
2. readFile(File file)
3. readFile(File file)
4. readFile(File file)
5. readFile(java.io.File file)
6. readFile(String filename)
7. readFile(String fileName)
8. readFile(String filename)
9. readFile(String filePath)