android Http 获取文件

/**
* request url and get json
* @param address url address
* @return
*/
public String requestJson(String address) {
StringBuffer sb = new StringBuffer();
try {
URL url = new URL(address);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
//get inputstream and read it
InputStream ins = conn.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(ins));
String line = null;
while ((line = br.readLine()) != null) {
sb.append(line);
}
} catch (Exception e) {
e.printStackTrace();
}
return sb.toString();

}