java - 如果不关闭 URL 连接会发生什么？

Question

如果不关闭下面的输入流，到底会发生什么？

InputStream is = new URL(queryUrl).openStream();

既然是 URL 连接，它是否足够智能，可以在请求后自动关闭？

我尝试查看文档，但内容相当模糊。根据我们收集的信息，这与执行 HTTPUrlConnection.getInputStream() 相同。

我只是想弄清楚不执行 is.close() 的影响。这肯定会导致资源泄漏吗？

Answer 1

当您调用close时，关联的系统资源将被释放。如果您查看方法 URL.openStream()

的实现

public final InputStream openStream() throws java.io.IOException {
   return openConnection().getInputStream();
}
public URLConnection openConnection() throws java.io.IOException {
   return handler.openConnection(this);
}

根据 javadoc，它返回一个 URLConnection

Invoking the close() methods on the InputStream or OutputStream of an URLConnection after a request may free network resources associated with this instance, unless particular protocol specifications specify different behaviours for it.

例如，如果您看到 HttpURLConnection ，他们的文档说:

Calling the close() methods on the InputStream or OutputStream of an HttpURLConnection after a request may free network resources associated with this instance but has no effect on any shared persistent connection. Calling the disconnect() method may close the underlying socket if a persistent connection is otherwise idle at that time.

干杯!!