关闭DataInputStream也会关闭FileInputStream吗？

Question

FileInputStream fstream = new FileInputStream(someFile.getPath()); 
DataInputStream in = new DataInputStream(fstream); 

如果我打电话给in.close()，它也会关闭fstream？我的代码是给GC例外如下：

java.lang.OutOfMemoryError：GC开销超过限制

Answer 1

是，DataInputStream.close()也将关闭你的FileInputStream。

Answer 2

你DataOutputStream继承了它从FilterOutputStreamclose() - 方法谁是documentation指出：

Closes this output stream and releases any system resources associated with the stream.

The close method of FilterOutputStream calls its flush method, and then calls the close method of its underlying output stream.

同样应该是所有Writer -implementations真（虽然它不是在文档中说明）。

---

为了避免流在Java中工作时遇到了内存问题，使用这个模式：

// Just declare the reader/streams, don't open or initialize them! 
BufferedReader in = null; 
try { 
    // Now, initialize them: 
    in = new BufferedReader(new InputStreamReader(in)); 
    // 
    // ... Do your work 
} finally { 
    // Close the Streams here! 
    if (in != null){ 
     try { 
      in.close(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 
} 

这看起来不太凌乱与Java7，因为它引入了AutoCloseable-interface，这是所有的流执行/作家/读者类。请参阅tutorial。