如何将字符串保存在本地缓冲区中，以便扫描程序可以重新读取它？

Question

I am working on some project which deals with HTML pages. I don't want to download the same page over and over again, so I want to save it locally. I use the Scanner a lot, however the Scanner need a InputStreamReader . For now I managed to save the HTML page to a local StringBuffer , however I can't make this StringBuffer be used with the Scanner .

Can I make this StringBuffer be used as an InputStreamReader ? If not, then what method can I use?

Answer 1

Scanner has a constructor taking a Readable . Of all Readable implementations, the CharBuffer seems to suit your purpose the most since you want to have a readable and writeable source.

String string = getItSomehow();
CharBuffer buffer = CharBuffer.wrap(string);
// ...
Scanner scanner = new Scanner(buffer);
// ...

Answer 2

Perhaps something along the lines of:

new InputStreamReader(new ByteArrayInputStream(new StringBuffer().toString().getBytes()));

If you want to do this right, you should send the HTTP GET request anyway, using the If-Modified-Since header, in order to correctly detect a page that has been changed.

Have you considered using a proper HTTP proxy though? That would save you the hassle of re-inventing the wheel in your application. An HTTP proxy would probably perform better and it would be usable by more than a single application.