newpdf_c#生成的pdf的大小為0kb

① C#如何讀取pdf文本

NuGet包管理器 ->程序包管理器控制台 ->輸入Install-Package Spire.PDF然後按回車安裝dll
然後使用下面代碼讀取PDF文本
using System;
using System.IO;
using System.Text;
using Spire.Pdf;
namespace ExtractText_PDF
{
class Program
{
static void Main(string[] args)
{
//實例化PdfDocument類對象，並載入PDF文檔
PdfDocument doc = new PdfDocument();
doc.LoadFromFile("sample.pdf");

//實例化一個StringBuilder 對象
StringBuilder content = new StringBuilder();

//遍歷文檔所有PDF頁面，提取文本
foreach (PdfPageBase page in doc.Pages)
{
content.Append(page.ExtractText());
}

//將提取到的文本寫為.txt格式並保存到本地路徑
String fileName = "獲取文本.txt";
File.WriteAllText(fileName, content.ToString());
}
}
}

② java創建pdf文件寫入不進去

通常需要用到用於讀、寫、編輯PDF文件的庫，你可以參考下面採用spire.pdf.jar來創建PDF的步驟及方法：

首先需要引入jar包。具體的引入方法可以自行網路搜索。
創建PdfDocument類的對象，並通過PdfDocument.getPages().add()方法添加頁碼。
定義標題文字。
創建PdfSolidBrush畫刷、PdfTrueTypeFont字體、PdfStringFormat字元串、Rectangle2D等對象，用於指定字元串繪制效果、字體、格式、繪制區域等。
通過PdfPageBase.getCanvas().drawString(body, font2, brush2, rect, format2)方法將內容繪制到PDF頁面。

下面附上詳細的代碼demo示例：

import com.spire.pdf.*;

import com.spire.pdf.graphics.*;

import java.awt.*;

import java.awt.geom.*;

import java.io.*;

public class CreatePdfDocumentInJava {

public static void main(String[] args) throws FileNotFoundException, IOException {

//創建PdfDocument對象
PdfDocument doc = new PdfDocument();

//添加一頁
PdfPageBase page = doc.getPages().add();

//標題文字
String title = "Java基礎語法";

//創建單色畫刷對象
PdfSolidBrush brush1 = new PdfSolidBrush(new PdfRGBColor(Color.BLUE));
PdfSolidBrush brush2 = new PdfSolidBrush(new PdfRGBColor(Color.BLACK));

//創建TrueType字體對象
PdfTrueTypeFont font1 = new PdfTrueTypeFont(new Font("宋體", Font.PLAIN, 14), true);
PdfTrueTypeFont font2 = new PdfTrueTypeFont(new Font("宋體", Font.PLAIN, 10), true);

//創建PdfStringFormat對象
PdfStringFormat format1 = new PdfStringFormat();
format1.setAlignment(PdfTextAlignment.Center);//設置文字居中

//使用drawString方法繪制標題文字
page.getCanvas().drawString(title, font1, brush1, new Point2D.Float((float) page.getActualBounds(true).getWidth() / 2, 0), format1);

//從txt文件讀取內容到字元串
String body = readFileToString("C:\Users\Administrator\Desktop\bodyText.txt");

//創建PdfStringFormat對象
PdfStringFormat format2 = new PdfStringFormat();
format2.setParagraphIndent(20);//設置段首縮進

//創建Rectangle2D對象
Rectangle2D.Float rect = new Rectangle2D.Float(0, 30, (float) page.getActualBounds(true).getWidth(), (float) page.getActualBounds(true).getHeight());

//使用drawString方法在矩形區域繪制主體文字
page.getCanvas().drawString(body, font2, brush2, rect, format2);

//保存到PDF文檔
doc.saveToFile("ouput.pdf");
}

//自定義方法讀取txt文件內容到字元串
private static String readFileToString(String filepath) throws FileNotFoundException, IOException {

StringBuilder sb = new StringBuilder();
String s = "";
BufferedReader br = new BufferedReader(new FileReader(filepath));

while ((s = br.readLine()) != null) {
sb.append(s + " ");
}
br.close();
String str = sb.toString();
return str;
}

}

③ java中如何實現向已有的PDF文件插入附件

可以用Spire.Pdf for Java類庫給PDF文檔添加附件，下面的代碼是插入Excel和Word附件給你參考：

import com.spire.pdf.annotations.*;

import com.spire.pdf.attachments.PdfAttachment;

import com.spire.pdf.graphics.*;

import java.awt.*;

import java.awt.geom.Dimension2D;

import java.awt.geom.Rectangle2D;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

public class AttachFiles {
public static void main(String[] args) throws IOException {

//創建PdfDocument對象

PdfDocument doc = new PdfDocument();

//載入PDF文檔

doc.loadFromFile("C:\Users\Administrator\Desktop\sample.pdf");

//添加附件到PDF

PdfAttachment attachment = new PdfAttachment("C:\Users\Administrator\Desktop\使用說明書.docx");

doc.getAttachments().add(attachment);

//繪制標簽

String label = "財務報表.xlsx";

PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial Unicode MS",Font.PLAIN,12),true);

double x = 35;

double y = doc.getPages().get(0).getActualSize().getHeight() - 200;

doc.getPages().get(0).getCanvas().drawString(label, font, PdfBrushes.getOrange(), x, y);

//添加註釋附件到PDF

String filePath = "C:\Users\Administrator\Desktop\財務報表.xlsx";

byte[] data = toByteArray(filePath);

Dimension2D size = font.measureString(label);

Rectangle2D bound = new Rectangle2D.Float((float) (x + size.getWidth() + 2), (float) y, 10, 15);

PdfAttachmentAnnotation annotation = new PdfAttachmentAnnotation(bound, filePath, data);

annotation.setColor(new PdfRGBColor(new Color(0, 128, 128)));

annotation.setFlags(PdfAnnotationFlags.Default);

annotation.setIcon(PdfAttachmentIcon.Graph);

annotation.setText("點擊打開財務報表.xlsx");

doc.getPages().get(0).getAnnotationsWidget().add(annotation);

//保存文檔

doc.saveToFile("Attachments.pdf");
}

//讀取文件到byte數組

public static byte[] toByteArray(String filePath) throws IOException {

File file = new File(filePath);

long fileSize = file.length();

if (fileSize > Integer.MAX_VALUE) {

System.out.println("file too big...");

return null;

}

FileInputStream fi = new FileInputStream(file);

byte[] buffer = new byte[(int) fileSize];

int offset = 0;

int numRead = 0;

while (offset < buffer.length && (numRead = fi.read(buffer, offset, buffer.length - offset)) >= 0) {

offset += numRead;

}

if (offset != buffer.length) {

throw new IOException("Could not completely read file "
+ file.getName());

}

fi.close();

return buffer;

}

效果：

④ 用c#如何提取pdf里的表格

添加spire.pdf.dll為引用，使用下面的代碼即可提取pdf中所有表格數據到txt文檔：

using System.IO;
using System.Text;
using Spire.Pdf;
using Spire.Pdf.Utilities;
namespace ExtractPdfTable
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument object
PdfDocument doc = new PdfDocument();
//Load the sample PDF file
doc.LoadFromFile(@"C:.pdf");
//Create a StringBuilder object
StringBuilder builder = new StringBuilder();
//Initialize an instance of PdfTableExtractor class
PdfTableExtractor extractor = new PdfTableExtractor(doc);
//Declare a PdfTable array
PdfTable[] tableList = null;
int tableNum = 1;
//Loop through the pages
for (int pageIndex = 0; pageIndex < doc.Pages.Count; pageIndex++)
{
//Extract tables from a specific page
tableList = extractor.ExtractTable(pageIndex);
//Determine if the table list is null
if (tableList != null && tableList.Length > 0)
{
//Loop through the table in the list
foreach (PdfTable table in tableList)
{
builder.Append("Table " + tableNum);
builder.Append(" ");
//Get row number and column number of a certain table
int row = table.GetRowCount();
int column = table.GetColumnCount();
//Loop though the row and colunm
for (int i = 0; i < row; i++)
{
for (int j = 0; j < column; j++)
{
//Get text from the specific cell
string text = table.GetText(i, j);
//Add text to the string builder
builder.Append(text + " ");
}
builder.Append(" ");
}
builder.Append(" ");
tableNum += 1;
}
}
}
//Write to a .txt file
File.WriteAllText("Table.txt", builder.ToString());
}
}
}

⑤ java導出的pdf文件是空白是因為什麼

導出的PDF大小是否是0kb？如果是0，那就是沒有把內容寫入到pdf,看下如下導出方法：

importjava.awt.*;

importjava.awt.geom.Point2D;

importjava.awt.geom.Rectangle2D;

importjava.io.*;

importcom.spire.pdf.PdfPageBase;

importcom.spire.pdf.graphics.*;

{

publicstaticvoidmain(String[]args)throwsFileNotFoundException,IOException{

//創建PdfDocument對象

PdfDocumentdoc=newPdfDocument();

//添加一頁

PdfPageBasepage=doc.getPages().add();

//標題文字

Stringtitle="Java基礎語法";

//創建單色畫刷對象

PdfSolidBrushbrush1=newPdfSolidBrush(newPdfRGBColor(Color.BLUE));

PdfSolidBrushbrush2=newPdfSolidBrush(newPdfRGBColor(Color.BLACK));

//創建TrueType字體對象

PdfTrueTypeFontfont1=newPdfTrueTypeFont(newFont("ArialUnicodeMS",Font.PLAIN,14),true);

PdfTrueTypeFontfont2=newPdfTrueTypeFont(newFont("ArialUnicodeMS",Font.PLAIN,10),true);

//創建PdfStringFormat對象

PdfStringFormatformat1=newPdfStringFormat();

format1.setAlignment(PdfTextAlignment.Center);//設置文字居中

//使用drawString方法繪制標題文字

page.getCanvas().drawString(title,font1,brush1,newPoint2D.Float(page.getActualBounds(true).width/2,0),format1);

//從txt文件讀取內容到字元串

Stringbody=readFileToString("C:\Users\Administrator\Desktop\bodyText.txt");

//創建PdfStringFormat對象

PdfStringFormatformat2=newPdfStringFormat();

format2.setParagraphIndent(20);//設置段首縮進

//創建Rectangle2D對象

Rectangle2D.Floatrect=newRectangle2D.Float(0,30,page.getActualBounds(true).width,page.getActualBounds(true).height);

//使用drawString方法在矩形區域繪制主體文字

page.getCanvas().drawString(body,font2,brush2,rect,format2);

//保存到PDF文檔

doc.saveToFile("ouput.pdf");

}

//自定義方法讀取txt文件內容到字元串

(Stringfilepath)throwsFileNotFoundException,IOException{

StringBuildersb=newStringBuilder();

Strings="";

BufferedReaderbr=newBufferedReader(newFileReader(filepath));

while((s=br.readLine())!=null){

sb.append(s+" ");

}

br.close();

Stringstr=sb.toString();

returnstr;

}

PDF到處效果如下圖：

⑥ c#生成的pdf的大小為0kb

0KB那就是生成的PDF文檔沒內容，看下你的代碼是哪裡有問題。建議可以通過PDF庫來實現生成文檔。可參考下面的代碼方法：

using System.Drawing;
using Spire.Pdf;
using Spire.Pdf.Graphics;
namespace CreatePDF_PDF
{
class Program
{
static void Main(string[] args)
{
//初始化一個PdfDocument類實例
PdfDocument document = new PdfDocument();
//聲明 PdfUnitConvertor和PdfMargins類對象
PdfUnitConvertor unitCvtr = new PdfUnitConvertor();
PdfMargins margins = new PdfMargins();
//設置頁邊距
margins.Top = unitCvtr.ConvertUnits(2.54f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point);
margins.Bottom = margins.Top;
margins.Left = unitCvtr.ConvertUnits(3.17f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point);
margins.Right = margins.Left;
//新添加一個A4大小的頁面
PdfPageBase page = document.Pages.Add(PdfPageSize.A4, margins);
//自定義PdfTrueTypeFont、PdfBrush實例，設置字體類型、字型大小和字體顏色
PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("楷體", 15f),true);
PdfBrush brush = PdfBrushes.Red;
//調用DrawString()方法在指定位置寫入文本
string text = ("《蝶戀花送春》樓外垂楊千萬縷，欲系青春，少住春還去。猶自風前飄柳絮，隨春且看歸何處？綠滿山川聞杜宇，便作無情，莫也愁人苦。把酒送春春不語，黃昏卻下瀟瀟雨。");
page.Canvas.DrawString(text, font, brush, 15, 13);
//載入圖片，並調用DrawImage()方法在指定位置繪入圖片
PdfImage image = PdfImage.FromFile("img.jpg");
float width = image.Width;
float height = image.Height;
page.Canvas.DrawImage(image, 15, 100, width, height);
//保存並打開文檔
document.SaveToFile("PDF創建.pdf");
System.Diagnostics.Process.Start("PDF創建.pdf");
}
}
}

執行程序後，在C: Studio 2013ProjectsCreatePDF_PDFCreatePDF_PDFinDebug路徑下可查看生成的文檔。可以看到生成的文檔大小，如圖：

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