從Internet擷取資料

利用HttpURLConnection對象,我們可以從網路中擷取網頁資料.
URL url = new URL("http://www.sohu.com");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5* 1000);//設定連線逾時

conn.setRequestMethod(“GET”);//以get方式發起請求

if (conn.getResponseCode() != 200) throw new RuntimeException("請求url失敗");

InputStream is = conn.getInputStream();//得到網路返回的輸入資料流
String result = readData(is, "GBK");

conn.disconnect();

 //第一個參數為輸入資料流,第二個參數為字元集編碼
public static String readData(InputStream inSream, String charsetName) throws Exception{
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len = -1;
while( (len = inSream.read(buffer)) != -1 ){
outStream.write(buffer, 0, len);
}

byte[] data = outStream.toByteArray();
outStream.close();
inSream.close();
return new String(data, charsetName);
}

利用HttpURLConnection對象,我們可以從網路中擷取檔案資料.
URL url = new URL("http://photocdn.sohu.com/20100125/Img269812337.jpg");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5* 1000);
conn.setRequestMethod("GET");

if (conn.getResponseCode() != 200) throw new RuntimeException("請求url失敗");
InputStream is = conn.getInputStream();
readAsFile(is, "Img269812337.jpg"); 

public static void readAsFile(InputStream inSream, File file) throws Exception{
FileOutputStream outStream = new FileOutputStream(file);
byte[] buffer = new byte[1024];
int len = -1;
while( (len = inSream.read(buffer)) != -1 ){
outStream.write(buffer, 0, len);
}
  outStream.close();
inSream.close();
}