DataInputStream关闭

Question

When I pass a InputStream to this method, does it close that?

public void foo(InputStream is) {
    DataInputStream dis = new DataInputStream(is);
    dis.close();
}

The superclass FilterInputStream redefines the close method as closing underlying inputstream too, so it will close the parameter is .

Does that action affect the inputstream at the caller?

Answer 1

Yes, the stream that is passed in will be closed.

Closing streams that you didn't open is hardly ever a good idea, so you should not close dis in this method.

DataInputStream holds no system resources of its own, so not closing it will not cause any leaks. You can simply leave it open. Alternatively you can return it from the method so that the caller can close it.

Answer 2

Yes, DataInputStream is a decorator-class over passed InputStream is . It isn't a InputStream it self.

So Essentially DataInputStream.close implies close on underlying InputStream .

/** * Closes this input stream and releases any system resources * associated with the stream. * This * method simply performs <code>in.close()</code>. * * @exception IOException if an I/O error occurs. * @see java.io.FilterInputStream#in */ public void close() throws IOException { in.close(); }

Answer 3

The InputStream will be closed.

Since Java SE 7 it is better to use try-with-resources so streams will be closed automatically.

Answer 4

You should close the InputStream in caller method only. Use Try Catch block whenever you are using any operation related to input or output streaming, if any of the stream remains open it will be handled by java

Answer 5

The class DataInputStream implements Coseable and AutoClose interfaces so the method close in class DataInputStream closes this input stream and releases any system resources associated with the stream. This method simply performs in.close() . Specified by close in interface Closeable , close in interface AutoCloseable Overrides close in class InputStream .

Throws: IOException - if an I/O error occurs.