Java InputStream、String、File相互转化

String --> InputStreamByteArrayInputStream stream = new ByteArrayInputStream(str.getBytes());InputStream --> StringString 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();}File --> InputStreamInputStream in = new FileInputStream(file); InputStream --> Filepublic void inputstreamtofile(InputStream ins,File file){   OutputStream os = new FileOutputStream(file);   int bytesRead = 0;   byte[] buffer = new byte[8192];   while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {      os.write(buffer, 0, bytesRead);   }   os.close();   ins.close();}