java io读书笔记(7) Closing Output Streams
2013-07-16 10:44 很大很老实 阅读(536) 评论(0) 编辑 收藏 举报输出完毕后,需要close这个stream,从而使操作系统释放相关的资源。举例:
public void close( ) throws IOException
并不是所有的stream都需要close,可是,诸如file或者network,打开后,需要关闭。
try { OutputStream out = new FileOutputStream("numbers.dat"); // Write to the stream... out.close( ); } catch (IOException ex) { System.err.println(ex); }
However, this code fragment has a potential leak. If an IOException is thrown while writing, the stream won't be closed. It's more reliable to close the stream in a finally block so that it's closed whether or not an exception is thrown. To do this you need to declare the OutputStream variable outside the try block. For example:
// Initialize this to null to keep the compiler from complaining // about uninitialized variables OutputStream out = null; try { out = new FileOutputStream("numbers.dat"); // Write to the stream... } catch (IOException ex) { System.err.println(ex); } finally { if (out != null) { try { out.close( ); } catch (IOException ex) { System.err.println(ex); } } }