使用 iText：java.lang.OutOfMemoryError：请求的数组大小超出 VM 限制
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Using iText: java.lang.OutOfMemoryError: Requested array size exceeds VM limit
提问by Bo ?berg
I'vew been using iText 4.2.1 and java 1.6 to generate PDF-files. My task is to add two fields having some random content using a template pdf. It works fine even with an 1GB large PDF. But now the environment demands java 7 and I run into this Out of memory-problem. I'v upgraded the iText to 5.5.3, but still the same issue. The code is trivial:
我一直在使用 iText 4.2.1 和 java 1.6 来生成 PDF 文件。我的任务是使用模板 pdf 添加具有一些随机内容的两个字段。即使使用 1GB 的大 PDF，它也能正常工作。但是现在环境需要 java 7，我遇到了内存不足的问题。我已经将 iText 升级到 5.5.3，但仍然是同样的问题。代码很简单：
public final class PdfHelper
{
public static void randomizePDFStream(InputStream in, OutputStream out)
{
try
{
PdfReader ReadInputPDF;
ReadInputPDF = new PdfReader(in);
-> crash PdfStamper stamper = new PdfStamper(ReadInputPDF, out);
HashMap<String, String> hMap = ReadInputPDF.getInfo();
hMap.put("Title", "RANDOM PDF TITLE: " + System.nanoTime() + ", " + System.currentTimeMillis());
hMap.put("Subject", "RANDOM PDF SUBJECT: " + System.currentTimeMillis() + ", " + System.nanoTime());
stamper.setMoreInfo(hMap);
stamper.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
This gives the following stack dump when using a 1GB large pdf file :
使用 1GB 大 pdf 文件时，这会提供以下堆栈转储：
Caught: java.util.concurrent.ExecutionException: java.lang.OutOfMemoryError: Requested array size exceeds VM limit
java.util.concurrent.ExecutionException: java.lang.OutOfMemoryError: Requested array size exceeds VM limit
at java_util_concurrent_Future$get.call(Unknown Source)
at Main.awaitCompletion(Main.groovy:222)
at Main$awaitCompletion.callCurrent(Unknown Source)
at Main.run(Main.groovy:113)
Caused by: java.lang.OutOfMemoryError: Requested array size exceeds VM limit
at com.itextpdf.text.io.StreamUtil.inputStreamToArray(StreamUtil.java:74)
at com.itextpdf.text.io.RandomAccessSourceFactory.createSource(RandomAccessSourceFactory.java:146)
at com.itextpdf.text.pdf.PdfReader.<init>(PdfReader.java:351)
at com.itextpdf.text.pdf.PdfReader.<init>(PdfReader.java:371)
at PdfHelper.randomizePDFStream(PdfHelper.java:65)
This is called from a groovy script with this basic code:
这是从带有以下基本代码的 groovy 脚本中调用的：
mPDFFiles[i] = new java.io.File(getTempDirectory(), String.format("temp_file_%s_%s.pdf", System.nanoTime(), i));
mPDFFiles[i].createNewFile();
input = new BufferedInputStream(new FileInputStream(mTemplateFiles[i]));
output = new BufferedOutputStream(new FileOutputStream(mPDFFiles[i]));
long start=System.currentTimeMillis();
PdfHelper.randomizePDFStream(input, output);
output.flush();
println "Conversion time: " + (System.currentTimeMillis()-start) + " ms."
Anyone having an idea how to get this to work?
任何人都知道如何让它发挥作用？
回答by Nirav Prajapati
You can use command-line parameters to increase the amount of memory available to Java. Here is an example of the command-line parameters that I use - you should change the numbers as appropriate for your needs and system memory capacity:
您可以使用命令行参数来增加 Java 可用的内存量。这是我使用的命令行参数的示例 - 您应该根据需要和系统内存容量更改数字：
Xms256m -Xmx1024m -XX:+DisableExplicitGC -Dcom.sun.management.jmxremote
-XX:PermSize=256m -XX:MaxPermSize=512m
回答by Johannes
Some options of what you could do:
你可以做的一些选择：
- Tell the JVM (which executes your Groovy code and the PdfStamper inside) to allow use of more memory (
-Xmxetc. Consult your JVM documentation). - Find an implementation that does not require to load the complete PDF into memory (at least not at once).
- 告诉 JVM（它执行您的 Groovy 代码和内部的 PdfStamper）以允许使用更多内存（
-Xmx等。请参阅您的 JVM 文档）。 - 找到一个不需要将完整的 PDF 加载到内存中的实现（至少不是一次）。
(I'm wondering why the implementation of iText and its PdfStamper is not efficient enough to accomplish your task without using a huge amount of memory...)
（我想知道为什么 iText 及其 PdfStamper 的实现效率不足以在不使用大量内存的情况下完成您的任务......）
回答by Lonzak
The error says "Requested array size exceeds VM limit" - the maximum size of an array is around 2GB (Integer.MAX_VALUE). The question is what VM are you running? 32 GB or 64 GB? You may try the following options (64 Bit VM):
错误显示“请求的数组大小超出 VM 限制” - 数组的最大大小约为 2GB (Integer.MAX_VALUE)。问题是你在运行什么虚拟机？32 GB 还是 64 GB？您可以尝试以下选项（64 位虚拟机）：
-XX:+UseCompressedOops
-XX:+UseCompressedOops
