java 下载网络资源的源码供参考

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现在的连接地址可以替换比较简单的方法进行 网络资源的下载。

 

package com.****.****;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
public class downFile {
//	private static String url = "http://daily3gp.com/vids/family_guy_penis_car.3gp";
private static String url = "http://219.138.125.22/myweb/mp3/CMP3/JH19.MP3";
public static void main(String[] args) {
downLoadGoogleIcon(url);
}
/**
* 依据URL获取文件名当为空时 设置文件名为 default.temp
* @param url
* @return
*/
private static String getFileNameFromUrl(String url){
if(url == null){
url = "default.temp";
}else {
if(url.lastIndexOf("/") != -1){
url = url.substring(url.lastIndexOf("/") + 1, url.length());
}else {
if(url.lastIndexOf(".") != -1){
url = url.substring(url.lastIndexOf(".") + 1, url.length());;
}else {
url = "default.temp";
}
}
}
System.out.println("the file name is " + url);
return url;
}
/**
* 下載网络资源
* @param downFileURL
*/
private static void downLoadGoogleIcon(String downFileURL) {
HttpURLConnection httpConnection = null; // 连接类
InputStream is = null;   // 输入流  网路部分
FileOutputStream fos = null;  // 输出流  文件部分
String icon = downFileURL;
byte buf[] = null;
try {
if (icon == null) {
throw new Exception("访问的URL不存在，请重试。");
}
URL url = new URL(icon);
// 文件路径
String path = "D:\\TEMP";
httpConnection = (HttpURLConnection) url.openConnection();
is = httpConnection.getInputStream(); // 获取输入流
File pathFile = new File(path);
if (!pathFile.exists()) {
pathFile.mkdirs();
}
fos = new FileOutputStream(new File(path + "\\" + getFileNameFromUrl(downFileURL)), true); // 获取输出流
buf = new byte[1024 * 8];
int len = 0;
int count = 0;
while ((len = is.read(buf)) > 0) {
count ++;
fos.write(buf, 0, len);
if(count == 64){
count = 0;
try {
System.out.println("download is paused!!!!");
Thread.sleep(1); // 性能优化利于资源分配
} catch (InterruptedException e) {
}
}
}
System.out.println("download is completed!!!!");
httpConnection.disconnect();
is.close();
fos.flush();
fos.close();
buf = null;
httpConnection = null;
is = null;
fos = null;
} catch (Exception e) {
System.out.println("downloading error!!!!");
} finally { // 记得在此回收资源虽然 繁琐但是影响很大。
try {
if (is != null) {
is.close();
}
is = null;
if (fos != null) {
fos.close();
}
fos = null;
if (httpConnection != null) {
httpConnection.disconnect();
httpConnection = null;
}
if (buf != null) {
buf = null;
}
} catch (Exception e2) {
}
}
}
}

上面包含了一些资源优化的一些理解，对大家有帮助，

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