java實現從網上下載檔案到本地
阿新 • • 發佈:2019-01-22
基本實現步驟:
1.建立http連線,獲取物件 connection
2.輸入流讀檔案
3.新建儲存路徑
4.輸出流寫入資料,並關閉流
public class test {
public static void main(String[] args) {getInternetRes("D:\\demoefile","http://imgsrc.baidu.com/image/c0%3Dshijue1%2C0%2C0%2C294%2C40/sign=3d2175db3cd3d539d530078052ee8325/b7003af33a87e950c1e1a6491a385343fbf2b425.jpg","112.jpg");
}
public static void getInternetRes(String newUrl, String oldUrl, String fileName) {
URL url = null;
HttpURLConnection con = null;
InputStream in = null;
FileOutputStream out = null;
try {
url = new URL(oldUrl);
//建立http連線,得到連線物件
con = (HttpURLConnection) url.openConnection();
//輸入流讀取檔案
in = con.getInputStream();
//轉化為byte陣列
byte[] data = getByteData(in);
//建立儲存的目錄、儲存的檔名
File file = new File(newUrl+today);
if (!file.exists()) {
file.mkdirs();
}
//修改檔名 用id重新命名
File res = new File(file + File.separator + fileName);
//寫入輸出流
out = new FileOutputStream(res);
out.write(data);
logger.info("下載 successfully!");
} catch (MalformedURLException e) {
logger.error("下載出錯!"+e.toString());
} catch (IOException e) {
logger.error("下載出錯!"+e.toString());
} finally {
//關閉流
try {
if (null != out)
out.close();
if (null != in)
in.close();
} catch (IOException e) {
logger.error("下載出錯!"+e.toString());
}
}
}
return null;
}
/**
*
* @Title: getByteData
* @Description: 從輸入流中獲取位元組陣列
* @author zml
* @date Sep 12, 2017 7:38:57 PM
*/
private static byte[] getByteData(InputStream in) throws IOException {
byte[] b = new byte[1024];
ByteArrayOutputStream bos = new ByteArrayOutputStream();
int len = 0;
while ((len = in.read(b)) != -1) {
bos.write(b, 0, len);
}
if(null!=bos){
bos.close();
}
return bos.toByteArray();
}