1. String --> InputStream

public static InputStream String2InputStream(String str) throws IOException{   ByteArrayInputStream stream = new ByteArrayInputStream(str.getBytes());   return stream;}

　2. InputStream --> String

public static String inputStream2String(InputStream is) throws IOException{    ByteArrayOutputStream baos = new ByteArrayOutputStream();    int i=-1;    while((i=is.read())!=-1){         baos.write(i);    }    return baos.toString(); }