Android File to Byte Array Read readFromFile(String fileName, int offset, int len)

Description

read From File

Declaration

public static byte[] readFromFile(String fileName, int offset, int len) 

Method Source Code

//package com.java2s;

import java.io.File;

import java.io.RandomAccessFile;

import android.util.Log;

public class Main {
    private static final String TAG = "SDK_Sample.Util";

    public static byte[] readFromFile(String fileName, int offset, int len) {
        if (fileName == null) {
            return null;
        }// w  w  w.  j a  v  a  2s . c  o m

        File file = new File(fileName);
        if (!file.exists()) {
            Log.i(TAG, "readFromFile: file not found");
            return null;
        }

        if (len == -1) {
            len = (int) file.length();
        }

        Log.d(TAG, "readFromFile : offset = " + offset + " len = " + len
                + " offset + len = " + (offset + len));

        if (offset < 0) {
            Log.e(TAG, "readFromFile invalid offset:" + offset);
            return null;
        }
        if (len <= 0) {
            Log.e(TAG, "readFromFile invalid len:" + len);
            return null;
        }
        if (offset + len > (int) file.length()) {
            Log.e(TAG, "readFromFile invalid file len:" + file.length());
            return null;
        }

        byte[] b = null;
        try {
            RandomAccessFile in = new RandomAccessFile(fileName, "r");
            b = new byte[len]; // ????????????????????
            in.seek(offset);
            in.readFully(b);
            in.close();

        } catch (Exception e) {
            Log.e(TAG, "readFromFile : errMsg = " + e.getMessage());
            e.printStackTrace();
        }
        return b;
    }
}

Related

1. fileToBytes(String filePath)
2. fileToByte(String filePath)
3. getBytesFromFile(File file)
4. readBytes(File file)
5. readBytes(String path)
6. read(File file)
7. buildDataFromFile(File file)
8. buildDataFromFile(String path)
9. buildDataFromFile(String path, int bufferSize)