Java String.split 内存泄漏? [英] Java String.split memory leak?

问题描述

我发现使用 String.substring 会导致与 String.split 相关的内存问题.

I found that using String.substring is known for memory issues related to String.split.

使用 String.split 是否存在内存泄漏?

Is there a memory leak in using String.split?

如果是，它的解决方法是什么?

If yes what is the work-around for it?

以下链接显示了 Java 中子字符串的正确用法.

Following link show correct usage of substring in Java.

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4513622

另一篇讨论子字符串中可能的 MLK 的博客.

One more blog which talk about possible MLK in substring.

http://nflath.com/2009/07/the-dangers-of-stringsubstring/

推荐答案

更新: 行为在 1.7.0_06 中发生了变化:请参阅这篇文章:Java 1.7.0_06 中对字符串内部表示的更改，位于 java-performance.info.

Update: Behavior has changed in 1.7.0_06: See this article: Changes to String internal representation made in Java 1.7.0_06 at java-performance.info.

正如 @finnw 所指出的，使用 String 时确实存在某种内存泄漏.子串.原因是 String.substring 只返回给定字符串的一部分的视图，即，底层字符串仍然保留在内存中.

As pointed out by @finnw there is indeed kind of a memory leak lurking around when using String.substring. The reason is that String.substring only returns a view of a portion of the given string, i.e., the underlying string is still kept in memory.

要强制创建与源无关的新字符串，您必须使用 new 关键字.即，你必须做例如

To force the creation of a new string, unrelated to the source, you'll have to use the new keyword. I.e., you'll have to do for instance

String[] parts = orig.split(";");
//String mySubstring = parts[i];               // keeps orig from being GC'd
String mySubstring = new String(parts[i]);     // creates a new string.

或者，也许更直接

String mySubstring = new String(orig.split(";")[i]);

<小时>

我必须说这种行为对我来说似乎不必要".它应该可以使用弱引用或其他一些技术来解决.(特别是考虑到 String 已经是一个特殊的类，Java 语言规范的一部分.)

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I must say that this behavior seems "unnecessary" to me. It should be solvable using weak references or some other technique. (Especially considering that String is already a special class, part of the Java language specification.)

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