1.inputStream.markSuppored() == true;

可以使用mark()和reset()来实现二次读取

2.当inputStream不支持mark和reset时,

从StackoverFlow找到答案

 

You can use  to copy the contents of the InputStream to a byte array, and then repeatedly read from the byte array using a ByteArrayInputStream. E.g.:

ByteArrayOutputStream baos = new ByteArrayOutputStream();org.apache.commons.io.IOUtils.copy(in, baos);byte[] bytes = baos.toByteArray();// eitherwhile (needToReadAgain) {    ByteArrayInputStream bais = new ByteArrayInputStream(bytes);    yourReadMethodHere(bais);}// orByteArrayInputStream bais = new ByteArrayInputStream(bytes);while (needToReadAgain) {    bais.reset();    yourReadMethodHere(bais);}