如何使PDF文件作爲字節數組讀取？

Question

編譯運行後顯示「沒有pdf打印機可用」，如何解決這個問題？

我在c：\ print.pdf中創建了一個文件（使用PHP TCPDF）。而我 試圖讀取字節數組文件，這樣我可以靜靜地打印 它沒有顯示出打印的任何彈出窗口等

我不能讓它的工作，任何人都可以請告訴指南如何閱讀 文件在字節數組？要做到以下幾點：

import java.io.ByteArrayInputStream; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.ObjectInputStream; 
import java.util.logging.Level; 
import java.util.logging.Logger; 
import javax.print.Doc; 
import javax.print.DocFlavor; 
import javax.print.DocPrintJob; 
import javax.print.PrintException; 
import javax.print.PrintService; 
import javax.print.PrintServiceLookup; 
import javax.print.SimpleDoc; 

public class print 
{ 
    private static Object pdfBytes; 

    // Byte array reader 
    public static byte[] getBytesFromFile(File file) throws IOException { 
     InputStream is = new FileInputStream(file); 
     long length = file.length(); 
     if (length > Integer.MAX_VALUE) {} 
     byte[] bytes = new byte[(int)length]; 

     int offset = 0; 
     int numRead = 0; 
     while (offset < bytes.length 
       && (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) { 
      offset += numRead; 
     } 
     if (offset < bytes.length) { 
      throw new IOException("Could not completely read file "+file.getName()); 
     } 
     is.close(); 
     return bytes; 
    }  

    // Convert Byte array to Object 
    public static Object toObject(byte[] bytes) 
    { 
     Object obj = null; 
     try { 
      ByteArrayInputStream bis = new ByteArrayInputStream(bytes); 
      ObjectInputStream ois = new ObjectInputStream (bis); 
      obj = ois.readObject(); 
     } catch (IOException ex) { 

     } catch (ClassNotFoundException ex) { 

     } 
     return obj; 
    } 

    private static File fl = new File("c:\\print.pdf");  
    public static void main(String argc[]) 
    { 
     DocFlavor flavor = DocFlavor.BYTE_ARRAY.PDF; 
     PrintService[] services = 
       PrintServiceLookup.lookupPrintServices(flavor, 
       null); 
     //Object pdfBytes = null; 
     try { 
      byte[] abc = getBytesFromFile(fl); 
      pdfBytes =toObject(abc); 
     } catch (IOException ex) { 
      Logger.getLogger(print.class.getName()).log(Level.SEVERE, null, ex); 
     } 

     if (services.length>0) 
     { 
      DocPrintJob printJob = services[0].createPrintJob(); 
      Doc document = new SimpleDoc(pdfBytes,flavor,null); 
      try { 
       printJob.print(document, null); 
      } catch (PrintException ex) { 
       Logger.getLogger(print.class.getName()).log(Level.SEVERE, null, ex); 
      } 
     } else { 
      System.out.println("no pdf printer available"); 

     } 
    } 

} 

我嘗試這樣做，它解決了我的靜音打印：https://gist.github.com/1094612

Answer 1

下面是關於如何文件讀入一個byte []的例子：

// Returns the contents of the file in a byte array. 
public static byte[] getBytesFromFile(File file) throws IOException { 
    InputStream is = new FileInputStream(file); 

    // Get the size of the file 
    long length = file.length(); 

    // You cannot create an array using a long type. 
    // It needs to be an int type. 
    // Before converting to an int type, check 
    // to ensure that file is not larger than Integer.MAX_VALUE. 
    if (length > Integer.MAX_VALUE) { 
     // File is too large 
    } 

    // Create the byte array to hold the data 
    byte[] bytes = new byte[(int)length]; 

    // Read in the bytes 
    int offset = 0; 
    int numRead = 0; 
    while (offset < bytes.length 
      && (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) { 
     offset += numRead; 
    } 

    // Ensure all the bytes have been read in 
    if (offset < bytes.length) { 
     throw new IOException("Could not completely read file "+file.getName()); 
    } 

    // Close the input stream and return bytes 
    is.close(); 
    return bytes; 
} 

Answer 2

import java.io.*; 
import java.util.*; 
import com.lowagie.text.*; 
import com.lowagie.text.pdf.*; 

public class ReadPDFFile { 
     public static void main(String[] args) throws IOException { 
       try { 
         Document document = new Document(); 
         document.open(); 
         PdfReader reader = new PdfReader("file.pdf"); 
         PdfDictionary dictionary = reader.getPageN(1); 
         PRIndirectReference reference = (PRIndirectReference) dictionary 
             .get(PdfName.CONTENTS); 
         PRStream stream = (PRStream) PdfReader.getPdfObject(reference); 
         byte[] bytes = PdfReader.getStreamBytes(stream); 
         PRTokeniser tokenizer = new PRTokeniser(bytes); 
         StringBuffer buffer = new StringBuffer(); 
         while (tokenizer.nextToken()) { 
           if (tokenizer.getTokenType() == PRTokeniser.TK_STRING) { 
             buffer.append(tokenizer.getStringValue()); 
           } 
         } 
         String test = buffer.toString(); 
         System.out.println(test); 
       } catch (Exception e) { 
       } 
     } 
} 

Answer 3

編譯並運行後顯示「沒有pdf打印機可用」

從我的文檔here和here，問題是你還沒有配置懂得如何打印與DocFlavour文件打印服務提供商的讀數。

一個解決方案是找到一個JAR文件，該文件爲PDF文檔實現PrinterService SPI並將其添加到類路徑中。谷歌搜索將顯示示例。 （我不能推薦任何特定的SP，因爲我從來沒有使用過它，所以你需要做一些調查/測試來找到適合你的。）