非阻塞I/O下载（可以跨服务器的下载）

        前些日子在公司做了一些上传下载的功能，这个非常好使就分享一下。然而一个观众都没有，那就当成自己的日记吧：

/**

* 非阻塞I/O下载

*

* @return boolean 是否成功

* @throws ParseException

*/

public boolean nioDownload(String preparePath, String realFileName, String saveName)

throws ParseException {

// httpUrl这个是下载地址

String httpUrl = preparePath;

String ext = realFileName.substring(realFileName.lastIndexOf("."), realFileName.length());

String workDirectory = getSystemRealDirectory() + getSystemWorkDirectory() + Global.getConfig("htword.accDir")

+ "/" + saveName + ext;

System.out.println("目标文件夹：" + workDirectory);

boolean flag = false;

// 下载网络文件

// Long startTime = System.nanoTime();

ReadableByteChannel rbc = null;

FileOutputStream fos = null;

try {

URL website = new URL(httpUrl);

System.out.println("下载地址：" + httpUrl);

rbc = Channels.newChannel(website.openStream());

fos = new FileOutputStream(workDirectory);//这个是最终下载到的位置

fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);

flag = true;

} catch (IOException e) {

flag = false;

e.printStackTrace();

} finally {

try {

if (fos != null) {

fos.close();

}

} catch (IOException e) {

e.printStackTrace();

}

try {

if (rbc != null) {

rbc.close();

}

} catch (IOException e) {

e.printStackTrace();

}

}

// Long elapsedTime = System.nanoTime() - startTime;

// if((elapsedTime / 1000000000.0)>3)

return flag;

}