java流关闭问题

Question

代码如下

DigestUtils.md5Hex(new FileInputStream(path));

new FileInputStream会启动个流,这个流需要关闭吗?
如果需要关闭,代码编程这样

InputStream inputStream = null;
String md5Hex = null;
try {
  inputStream = new FileInputStream(docPath);
  md5Hex = DigestUtils.md5Hex(inputStream);
} catch (FileNotFoundException e1) {
  e1.printStackTrace();
} catch (IOException e) {
  e.printStackTrace();
} finally {
  if (inputStream != null) {
    try {
      inputStream.close();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

我还发现
DigestUtils.md5Hex执行之之前inputStream.available();有值,执行后inputStream.available();的值变为0,是不是inputStream.available();的值为0就不需要关闭流

Answer 1

请用java 7的try-resource语法：

try(InputStream inputStream = new FileInputStream(docPath)){
    String md5Hex = DigestUtils.md5Hex(inputStream);
}