SimpleDownloader.java

/**
 * Copyright (c) 2012-2013, Michael Yang 杨福海 (www.yangfuhai.com).
 *
 * 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.
 */
package net.tsz.afinal.bitmap.download;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;

import android.util.Log;

/**
 * @title 根据 图片url地址下载图片 可以是本地和网络
 * @author 杨福海（michael） www.yangfuhai.com
 */
public class SimpleDownloader implements Downloader {

	private static final String TAG = SimpleDownloader.class.getSimpleName();
	private static final int IO_BUFFER_SIZE = 8 * 1024; // 8k

	public byte[] download (String urlString){
		if (urlString == null)
			return null;

		if (urlString.trim().toLowerCase().startsWith("http")) {
			return getFromHttp(urlString);
		}else if(urlString.trim().toLowerCase().startsWith("file:")){
			try {
				File f = new File(new URI(urlString));
				if (f.exists() && f.canRead()) {
					return getFromFile(f);
				}
			} catch (URISyntaxException e) {
				Log.e(TAG, "Error in read from file - " + urlString + " : " + e);
			}
		}else{
			File f = new File(urlString);
			if (f.exists() && f.canRead()) {
				return getFromFile(f);
			}
		}
		
		return null;
	}

	private byte[] getFromFile(File file) {
		if(file == null) return null;
		
		FileInputStream fis = null;
		try {
			fis = new FileInputStream(file);
			ByteArrayOutputStream baos = new ByteArrayOutputStream();
			int len = 0;
			byte[] buffer = new byte[1024];
			while ((len = fis.read(buffer)) != -1) {
				baos.write(buffer, 0, len);
			}
			return baos.toByteArray();
		} catch (Exception e) {
			Log.e(TAG, "Error in read from file - " + file + " : " + e);
		} finally {
			if (fis != null) {
				try {
					fis.close();
					fis = null;
				} catch (IOException e) {
					// do nothing
				}
			}
		}

		return null;
	}

	private byte[] getFromHttp(String urlString) {
		HttpURLConnection urlConnection = null;
		BufferedOutputStream out = null;
		FlushedInputStream in = null;

		try {
			final URL url = new URL(urlString);
			urlConnection = (HttpURLConnection) url.openConnection();
			in = new FlushedInputStream(new BufferedInputStream(urlConnection.getInputStream(), IO_BUFFER_SIZE));
			ByteArrayOutputStream baos = new ByteArrayOutputStream();
			int b;
			while ((b = in.read()) != -1) {
				baos.write(b);
			}
			return baos.toByteArray();
		} catch (final IOException e) {
			Log.e(TAG, "Error in downloadBitmap - " + urlString + " : " + e);
		} finally {
			if (urlConnection != null) {
				urlConnection.disconnect();
			}
			try {
				if (out != null) {
					out.close();
				}
				if (in != null) {
					in.close();
				}
			} catch (final IOException e) {
			}
		}
		return null;
	}

	
	public class FlushedInputStream extends FilterInputStream {
		public FlushedInputStream(InputStream inputStream) {
			super(inputStream);
		}

		@Override
		public long skip(long n) throws IOException {
			long totalBytesSkipped = 0L;
			while (totalBytesSkipped < n) {
				long bytesSkipped = in.skip(n - totalBytesSkipped);
				if (bytesSkipped == 0L) {
					int by_te = read();
					if (by_te < 0) {
						break; // we reached EOF
					} else {
						bytesSkipped = 1; // we read one byte
					}
				}
				totalBytesSkipped += bytesSkipped;
			}
			return totalBytesSkipped;
		}
	}
}