Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright (C) 2009 University of Washington
 *
 * Licensed 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 android.util.Log;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;

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

import java.math.BigInteger;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Main {
    private final static String t = "FileUtils";

    public static String getMd5Hash(File file) {
        try {
            // CTS (6/15/2010) : stream file through digest instead of handing it the byte[]
            MessageDigest md = MessageDigest.getInstance("MD5");
            int chunkSize = 256;

            byte[] chunk = new byte[chunkSize];

            // Get the size of the file
            long lLength = file.length();

            if (lLength > Integer.MAX_VALUE) {
                Log.e(t, "File " + file.getName() + "is too large");
                return null;
            }

            int length = (int) lLength;

            InputStream is = null;
            is = new FileInputStream(file);

            int l = 0;
            for (l = 0; l + chunkSize < length; l += chunkSize) {
                is.read(chunk, 0, chunkSize);
                md.update(chunk, 0, chunkSize);
            }

            int remaining = length - l;
            if (remaining > 0) {
                is.read(chunk, 0, remaining);
                md.update(chunk, 0, remaining);
            }
            byte[] messageDigest = md.digest();

            BigInteger number = new BigInteger(1, messageDigest);
            String md5 = number.toString(16);
            while (md5.length() < 32)
                md5 = "0" + md5;
            is.close();
            return md5;

        } catch (NoSuchAlgorithmException e) {
            Log.e("MD5", e.getMessage());
            return null;

        } catch (FileNotFoundException e) {
            Log.e("No Cache File", e.getMessage());
            return null;
        } catch (IOException e) {
            Log.e("Problem reading from file", e.getMessage());
            return null;
        }

    }
}