如何在Java中高效地读取包含大量小项目的大型XML文件？ [英] How to read large XML file consisting of large number of small items efficiently in Java?

问题描述

我有一个较大的XML文件，其中包含相对固定大小的项目，即

I have a large XML file that consists of relatively fixed size items i.e.

<rootElem>
  <item>...</item>

  <item>...</item>
  <item>...</item>
<rootElem>

项元素相对较浅，通常相当小（<100 KB），但可能有很多（数十万）。这些项目是完全独立的。

The item elements are relatively shallow and typically rather small ( <100 KB), but there may be a lot of them (hundreds of thousands). The items are completely independent of each other.

如何在Java中有效地处理该文件？我无法以DOM形式读取整个文件，而且我不喜欢使用SAX，因为代码变得相当复杂。我想避免将文件拆分成较小的部分。

How could I process the file efficiently in Java? I can't read the whole file in as DOM, and I don't like to use SAX because the code gets rather complex. I'd like to avoid splitting the file to smaller pieces.

如果我可以将每个 项目 元素（一次一个）作为单独的DOM文档，我可以使用JAXB等工具进行处理。基本上我只想在所有项目中循环一次。

Optimal would be if I could obtain each item element, one at a time, as a separate DOM document, that I could process using tools like JAXB. Basically I just want to loop once over all the items.

我认为这是一个相当常见的问题。

I would think that this is a rather common problem.

推荐答案

Java 6有一个 StAX支持。它采用像SAX这样的流处理方式，但是使用了一种基于拉式的方法，可以实现更简单的处理代码。

Java 6 has a StAX support. It perfroms a stream processing like SAX, but uses a pull-based approach which leads to the simplier handling code.

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