Android中从网络获取数据

在编写Android应用时，有时会需要从Internet上获取数据。

包括获取网页数据和文件数据。

1.获取网络上的网页数据

通过HttpURLConnection对象,从网络中获取网页数据.

URL url = new URL("http://www.sina.com");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5* 1000);//设置连接超时
conn.setRequestMethod("GET");//以get方式发起请求
if (conn.getResponseCode() != 200) throw new RuntimeException("请求url失败");
InputStream is = conn.getInputStream();//得到网络返回的输入流
String result = readData(is, "GBK");
conn.disconnect();

//第一个参数为输入流,第二个参数为字符集编码
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);
}

2.获取网络上的文件数据

通过HttpURLConnection对象,可以从网络中获取文件数据.

URL url = new URL("http://photocdn.sina.com/xxx");//文件地址
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5* 1000);
conn.setRequestMethod("GET");
if (conn.getResponseCode() != 200) throw new RuntimeException("请求url失败");
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();
}