String --> InputStream
InputStream String2InputStream(String str){
ByteArrayInputStream stream = new ByteArrayInputStream(str.getBytes());
return stream;
}
InputStream --> String
String inputStream2String(InputStream is){
BufferedReader in = new BufferedReader(new InputStreamReader(is));
StringBuffer buffer = new StringBuffer();
String line = "";
while ((line = in.readLine()) != null){
buffer.append(line);
}
return buffer.toString();
}