如何使用iText制作多个页面的PDF Java

问题描述：

我有一个包含水果的列表，我试图通过使用for循环将列表的果实与其数据放入JPanel。我想在屏幕上填写4乘2（总共8）的JPanel到一个页面。在下面的图片中查看结果。如何使用iText制作多个页面的PDF Java

在代码示例中，我没有使用fruitslist，而是使用了一个for循环，代表我拥有11个水果>> for（int i = 0; i < 11; i ++）的列表。因此，我期望得到的是一个2页的PDF文件。第一个包含8个面板，第二个包含3个面板。我想知道的是，如何让应用程序获得多个分页的PDF，其中一个页面只包含最多8个面板。任何帮助，将不胜感激。

// JFrame中//

import com.itextpdf.text.Document; 
import com.itextpdf.text.PageSize; 
import com.itextpdf.text.pdf.PdfContentByte; 
import com.itextpdf.text.pdf.PdfTemplate; 
import com.itextpdf.text.pdf.PdfWriter; 
import java.awt.*; 
import java.io.FileOutputStream; 
import java.util.Date; 
import javax.swing.*; 

public class SmallList extends JFrame { 

GridLayout gridLayout = new GridLayout(0,4); 

public SmallList(String name) { 
    super(name); 
    setResizable(false); 
} 

public void addComponentsToPane(final Container pane) { 
    final JPanel components = new JPanel(); 
    components.setLayout(gridLayout); 

    for(int i = 0; i < 11; i++) { 
     JPanel jPanel = new javax.swing.JPanel(); 
     JSeparator seperator = new javax.swing.JSeparator(); 
     JSeparator separator1 = new javax.swing.JSeparator(); 
     JLabel nameLabel = new javax.swing.JLabel(); 
     JLabel unitLabel = new javax.swing.JLabel(); 
     JLabel priceLabel = new javax.swing.JLabel(); 
     JLabel centLabel = new javax.swing.JLabel(); 
     JLabel comma = new javax.swing.JLabel(); 
     jPanel.setBackground(new java.awt.Color(255, 255, 255)); 
     jPanel.setAlignmentX(0.0F); 
     jPanel.setAlignmentY(0.0F); 
     jPanel.setMaximumSize(null); 
     jPanel.setPreferredSize(new java.awt.Dimension(203, 289)); 

     seperator.setBackground(new java.awt.Color(0, 0, 0)); 

     separator1.setBackground(new java.awt.Color(0, 0, 0)); 

     nameLabel.setFont(new java.awt.Font("Tahoma", 0, 14)); // NOI18N 
     nameLabel.setHorizontalAlignment(javax.swing.SwingConstants.CENTER); 

     unitLabel.setFont(new java.awt.Font("Tahoma", 0, 40)); // NOI18N 
     unitLabel.setHorizontalAlignment(javax.swing.SwingConstants.CENTER); 

     priceLabel.setFont(new java.awt.Font("Tahoma", 0, 90)); // NOI18N 
     priceLabel.setHorizontalAlignment(javax.swing.SwingConstants.CENTER); 
     priceLabel.setText(" "); 

     centLabel.setFont(new java.awt.Font("Tahoma", 0, 55)); // NOI18N 
     centLabel.setText(" "); 

     comma.setFont(new java.awt.Font("Tahoma", 0, 36)); // NOI18N 
     comma.setHorizontalAlignment(javax.swing.SwingConstants.CENTER); 
     comma.setText(","); 

     javax.swing.GroupLayout jPanelLayout = new javax.swing.GroupLayout(jPanel); 
     jPanel.setLayout(jPanelLayout); 
     jPanelLayout.setHorizontalGroup(
      jPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addComponent(seperator) 
      .addComponent(separator1) 
      .addGroup(jPanelLayout.createSequentialGroup() 
       .addContainerGap() 
       .addGroup(jPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
        .addComponent(unitLabel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
        .addComponent(nameLabel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanelLayout.createSequentialGroup() 
         .addComponent(priceLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 101, javax.swing.GroupLayout.PREFERRED_SIZE) 
         .addGroup(jPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
          .addGroup(jPanelLayout.createSequentialGroup() 
           .addComponent(comma) 
           .addGap(0, 0, Short.MAX_VALUE)) 
          .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanelLayout.createSequentialGroup() 
           .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) 
           .addComponent(centLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 77, javax.swing.GroupLayout.PREFERRED_SIZE))))) 
       .addContainerGap()) 
     ); 
     jPanelLayout.setVerticalGroup(
      jPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGroup(jPanelLayout.createSequentialGroup() 
       .addGap(6, 6, 6) 
       .addComponent(unitLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 34, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addComponent(seperator, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addGroup(jPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
        .addGroup(jPanelLayout.createSequentialGroup() 
         .addGap(32, 32, 32) 
         .addGroup(jPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) 
          .addComponent(priceLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 130, javax.swing.GroupLayout.PREFERRED_SIZE) 
          .addComponent(comma))) 
        .addGroup(jPanelLayout.createSequentialGroup() 
         .addGap(29, 29, 29) 
         .addComponent(centLabel))) 
       .addGap(32, 32, 32) 
       .addComponent(separator1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) 
       .addComponent(nameLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 29, javax.swing.GroupLayout.PREFERRED_SIZE) 
       .addContainerGap()) 
     ); 
     jPanel.setBorder(BorderFactory.createLineBorder(Color.BLACK)); 

     components.add(jPanel); 
    } 

    pane.add(components); 
    print(); 
} 

private void print() { 
    Date date = new Date(); 
    try { 
     JFrame f = new JFrame("Productlijst klein"); 
     f.add(this.getComponent(0)); 
     f.setUndecorated(true); 
     f.pack(); 
     f.setVisible(true); 

     Document document = new Document(PageSize.A4.rotate()); 
     String fileName = "prijslijst" + date.getTime() + ".pdf"; 
     PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(fileName)); 
     document.open(); 

     PdfContentByte cb = writer.getDirectContent(); 
     PdfTemplate template = cb.createTemplate(PageSize.A4.getHeight(), PageSize.A4.getWidth()); 
     Graphics2D g2d = template.createGraphics(f.getWidth(), f.getHeight()); 
     f.paintAll(g2d); 
     g2d.dispose(); 
     cb.addTemplate(template, 0, 0); 

     document.close();   

    } catch (Exception e) { 
     System.out.println(e); 
    } 
} 

/** 
* Create the GUI and show it. For thread safety, 
* this method is invoked from the 
* event dispatch thread. 
*/ 
private static void createAndShowGUI() { 
    //Create and set up the window. 
    SmallList frame = new SmallList("Fruit - kleine afmeting"); 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    //Set up the content pane. 
    frame.addComponentsToPane(frame.getContentPane()); 
    //Display the window. 
    frame.pack(); 
    frame.setVisible(true); 
} 

public static void main(String[] args) { 
    /* Use an appropriate Look and Feel */ 
    try { 
     //UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); 
     UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel"); 
    } catch (UnsupportedLookAndFeelException ex) { 
     ex.printStackTrace(); 
    } catch (IllegalAccessException ex) { 
     ex.printStackTrace(); 
    } catch (InstantiationException ex) { 
     ex.printStackTrace(); 
    } catch (ClassNotFoundException ex) { 
     ex.printStackTrace(); 
    } 
    /* Turn off metal's use of bold fonts */ 
    UIManager.put("swing.boldMetal", Boolean.FALSE); 

    //Schedule a job for the event dispatch thread: 
    //creating and showing this application's GUI. 
    javax.swing.SwingUtilities.invokeLater(new Runnable() { 
     public void run() { 
      createAndShowGUI(); 
     } 
    }); 
}

}

其结果将是这样的，当应用程序结束的代码。一页将包含8个水果JPanels。

请提供一个最小的例子显示了正是你尝试创建多页PDF。大部分代码与您关于PDF生成的问题无关。 – Muto

您正在使用低级别方法添加内容（如使用ContentByte所示），您必须自己处理分页符。如果有帮助，您目前正在执行的操作可以被视为绘制在无限大的画布上，而不是添加到页面大小的画布（通过'cb.addTemplate（）'）。你画了11个标签，你看不到底部3，因为它们是由页面绘制的。 –

感谢您的回复，Muto看看print（）方法。问题是我不知道如何创建一个多页面的PDF。这就是我实际要求的。 – Hans

答

解决方案

而不是使用PDF格式的图形，简单地利用iText让你的表在PDF中。拆分模型（底层数据）和您的图形表示（用户界面或PDF文档）始终是一个好主意，因为这可以让您在将来获得灵活性。
为表示例代码（这很可能是你怎么也得建立你的PDF）可以在iText的网页中找到
https://developers.itextpdf.com/content/itext-7-examples/itext-7-tables
明确插入分页符已经问（并回答）这里
how can I make a page break using itext

如何使用iText制作多个页面的PDF Java

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