java - 为什么 StAX 类没有在 Java 7 中针对 ARM 进行改造

Question

我希望在 Java 7 中发现 XMLStreamReader 是 AutoCloseable。然而，事实并非如此。是否有技术原因导致 StAX 读写器接口(interface)没有(或不应该) retrofit 以实现 AutoCloseable ？他们已经有了close方法，其意图与AutoCloseable的close方法没有区别。

Answer 1

如果你仔细观察 close() method of AutoCloseable :

Closes this resource, relinquishing any underlying resources. This method is invoked automatically on objects managed by the try-with-resources statement.

甚至Closeable close() method :

Closes this stream and releases any system resources associated with it. If the stream is already closed then invoking this method has no effect.

而 close() method of XMLStreamReader说:

Frees any resources associated with this Reader. This method does not close the underlying input source.

实际上，输入源是由 Reader 管理的它实现了 Closeable 接口(interface)。因此，读者可以在 try-with-ressource 中接近。

例如:

    XMLInputFactory factory = XMLInputFactory.newInstance();
    XMLStreamReader reader = null;
    try (FileReader fr = new FileReader("file.xml")) { //Will close the FileReader
        reader = factory.createXMLStreamReader(fr);
        reader.close();
    }
    catch (XMLStreamException ex) {
        if(reader!=null)try {
            reader.close();
        } catch (XMLStreamException ex1) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex1);
        }
    }