Question

我正在尝试从大约5000个表单列表中创建一个单独的pdf文档，这些表单是用我用C＃编写的ASP.NET MVC网站中的对象列表标记的。一旦我执行大约1500个表单的冲压过程，我就会得到一个Out of Memory Exception。如果我将对象列表限制在1500个以下的对象中，我就不会收到错误。

这是模仿表单数据的数据对象：

public class MyPageData
{
    public string Name { get; set; }
    public string Description { get; set; }
    public decimal DueAmount { get; set; }
    public decimal PaidAmount { get; set; }
}

创建文档的代码。注意模板是pdf格式，Stream是使用写访问权限创建的FileStream对象，无文件共享。

public class DocumentBuilder
{
    public static void FillDocument(IList<MyPageData> pages, string template, Stream outputFile)
    {
        using (Document document = new Document())
        {
            using (PdfSmartCopy copy = new PdfSmartCopy(document, outputFile))
            {
                document.Open();
                foreach (var page in pages)
                {
                    PdfReader reader = new PdfReader(StampPage(template, page));
                    copy.AddPage(copy.GetImportedPage(reader, 1));
                    copy.FreeReader(reader);
                }
            }
        }
    }

    private static byte[] StampPage(string template, MyPageData page)
    {
        PdfReader reader = new PdfReader(template);
        using (MemoryStream stream = new MemoryStream())
        {
            using (PdfStamper stamper = new PdfStamper(reader, stream))
            {
                AcroFields fields = stamper.AcroFields;
                FillFields(fields, page);
                stamper.FormFlattening = true;
                stamper.Writer.Flush();
            }
            return stream.ToArray();
        }
    }

    private static void FillFields(AcroFields fields, MyPageData page)
    {
        fields.SetField("Name", page.Name);
        fields.SetField("Description", page.Description);
        fields.SetField("DueAmount", page.DueAmount.ToString());
        fields.SetField("PaidAmout", page.PaidAmount.ToString());
    }
}

我已经遍及iText和iTextSharp文档了，我相信我的代码是正确的。我确实试图按照演示Here来压缩文档，但是在标记时仍会抛出错误。有什么想法或建议吗？

Answer 1

（尚未回答）

我刚尝试使用以下代码运行5,000代码而没有问题。第一个块创建一个匹配您的模板，第二个块填充您的类的一些示例数据，第三个块实际实现您的逻辑。您的代码与此之间有什么截然不同的东西吗？这会给你一个OOM例外吗？

//Creates our sample template
var templateFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "template.pdf");
using (var fs = new FileStream(templateFile, FileMode.Create, FileAccess.Write, FileShare.None)) {
    using (var doc = new Document()) {
        using (var writer = PdfWriter.GetInstance(doc, fs)) {
            doc.Open();

            var fields = new string[] { "Name", "Description", "DueAmount", "PaidAmout" };
            var y = 700;
            foreach (var f in fields) {
                var tf = new TextField(writer, new iTextSharp.text.Rectangle(100, y, 400, y + 50), f);
                writer.AddAnnotation(tf.GetTextField());
                y -= 200;
            }

            doc.Close();
        }
    }
}

//Create our final PDF
var pages = new List<MyPageData>();
for (decimal i = 0; i < 5000; i++) {
    pages.Add(new MyPageData() { Name = "Chris", Description = "Cheese", DueAmount = i, PaidAmount = i * 0.5m });
}

//Create our file
var outputFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "output.pdf");
using (var fs = new FileStream(outputFile, FileMode.Create, FileAccess.Write, FileShare.None)) {
    DocumentBuilder.FillDocument(pages, templateFile, fs);
}

修改

我将它增加到75个字段，虽然需要更长的时间，但仍然没有得到OOM。为了进行测试，我将您的MyPageData课程更改为：

public class MyPageData { public string[] StringData { get; set; } }

您的DocumentBuilder FillFields来：

private static void FillFields(AcroFields fields, MyPageData page) { var fieldCount = 75; for (var j = 0; j < fieldCount; j++) { fields.SetField("Field_" + j.ToString(), page.StringData[j]); } }

我的模板和示例数据创建到：

var fieldCount = 75; //Creates our sample template var templateFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "template.pdf"); using (var fs = new FileStream(templateFile, FileMode.Create, FileAccess.Write, FileShare.None)) { using (var doc = new Document()) { using (var writer = PdfWriter.GetInstance(doc, fs)) { doc.Open(); var y = 800; //Create 75 fields for (var j = 0; j < fieldCount; j++) { var tf = new TextField(writer, new iTextSharp.text.Rectangle(100, y, 400, y + 10), "Field_" + j.ToString()); tf.Options = tf.Options | TextField.MULTILINE; writer.AddAnnotation(tf.GetTextField()); y -= 10; } doc.Close(); } } } //Create our sample data var pages = new List<MyPageData>(); for (decimal i = 0; i < 5000; i++) { var stringData = new List<string>(); for (var j = 0; j < fieldCount; j++) { stringData.Add("Data_" + j.ToString()); } pages.Add(new MyPageData() { StringData = stringData.ToArray() }); }

标记超过1500页时，iTextSharp Out of Memory异常

1 个答案: