Java InputStream、String、File相互转化

转自：http://blog.sina.com.cn/s/blog_a000da9d010121bl.html

String --> InputStream
ByteArrayInputStream stream = new ByteArrayInputStream(str.getBytes());

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();

}

File --> InputStream

InputStream in = new FileInputStream(file);

 

InputStream --> File

public 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);

   }