差異處
這裏顯示兩個版本的差異處。
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java:basic:urlconnection [2018/09/25 09:58] tony [How to?] |
java:basic:urlconnection [2023/06/25 09:48] |
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| 行 1: | 行 1: | ||
| - | {{tag>java}} | ||
| - | ====== URLConnection ====== | ||
| - | ===== Problem ===== | ||
| - | URL的openStream與URLConnection的getLastModified後將會有兩個連線，如果是在有連線數限制的伺服器上，將會造成問題。 | ||
| - | <code java> | ||
| - | public static void main(String[] args) { | ||
| - | InputStream is = null; | ||
| - | try { | ||
| - | URL url = new URL("http://10.134.15.15/test.txt"); | ||
| - | URLConnection urlConn = url.openConnection(); | ||
| - | System.out.println(urlConn.getLastModified()); | ||
| - | is = url.openStream(); | ||
| - | // some operations | ||
| - | } catch (Exception e) { | ||
| - | logger.error("", e); | ||
| - | } finally { | ||
| - | Cleaner.close(is); | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | ===== How to? ===== | ||
| - | 最簡單作法就是重複使用URLConnection所建立出來的連線: | ||
| - | <code java> | ||
| - | public static void main(String[] args) { | ||
| - | InputStream is = null; | ||
| - | try { | ||
| - | URL url = new URL("http://10.134.15.15/test.txt"); | ||
| - | URLConnection urlConn = url.openConnection(); | ||
| - | System.out.println(urlConn.getLastModified()); | ||
| - | is = urlConn.getInputStream(); | ||
| - | // some operations | ||
| - | } catch (Exception e) { | ||
| - | logger.error("", e); | ||
| - | } finally { | ||
| - | Cleaner.close(is); | ||
| - | } | ||
| - | } | ||
| - | </code> | ||
| - | 另一個方法就是避免URL的openStream與URLConnection的操作同時使用即可。在連線的釋放，我是直接close InputStream；假如有cast為HttpURLConnection可以使用disconnect。 | ||
| - | ===== Refernce ===== | ||
| - | * [[http://kingori.co/minutae/2013/04/httpurlconnection-disconnect/|Do we need to call HttpURLConnection.disconnect()?]] | ||
| - | * [[http://stackoverflow.com/questions/9150200/closing-urlconnection-and-inputstream-correctly|Closing URLConnection and InputStream correctly?]] | ||
| - | ===== ===== | ||
| - | ---- | ||
| - | \\ | ||
| - | ~~DISQUS~~ | ||
