创建复杂PDF

上篇文章展示了使用Java和Aspose.PDF简单步骤。本文中，我们将使用Java和Aspose.PDF创建更复杂的文档结构。此示例中，我们将创建包含图片、两个文本片段（标题和段落）和表格。

创建文档参考以下步骤：

实例化一个Document对象。本步骤中将创建一个空的PDF文档，只包含一些metadata没有任何页面。
添加Page到Document对象。至此，文档有一个Page。
添加Image。
- 加载image流
- 添加图片到Page Resources的图片集合
- GSave：保存当前图行状态
- 创建一个Matrix对象
- ConcatenateMatrix：定义图像如何放置
- Do：绘制图像
- GRestore：恢复图形状态
创建一个header的文本片段。header使用Arial、24pt 字体并且居中。
添加header到页面段落中。
添加说明文本片段。使用Arial、24pt 字体并且居中。
添加说明文本片段到页面段落中。
创建table，设置table属性。
添加table到页面段落中。
10.保存文档。

具体代码如下：

package com.aspose.pdf.examples;

/**
 * Complex Example
 */

import java.io.FileNotFoundException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.time.Duration;
import java.time.LocalTime;

import com.aspose.pdf.*;
import com.aspose.pdf.operators.ConcatenateMatrix;
import com.aspose.pdf.operators.Do;
import com.aspose.pdf.operators.GRestore;
import com.aspose.pdf.operators.GSave;

public final class ComplexExample {

    private ComplexExample() {
    }

    private static Path _dataDir = Paths.get("/home/admin1/pdf-examples/");

    public static void main(String[] args) throws FileNotFoundException {
        // Initialize document object
        Document document = new Document();
        // Add page
        Page page = document.getPages().add();

        // -------------------------------------------------------------
        // Add image
        Path imageFileName = Paths.get(_dataDir.toString(),"logo.png");
        java.io.FileInputStream imageStream = new java.io.FileInputStream(new java.io.File(imageFileName.toString()));
        // Add image to Images collection of Page Resources
        page.getResources().getImages().add(imageStream);

        // Using GSave operator: this operator saves current graphics state
        page.getContents().add(new GSave());
        Rectangle _logoPlaceHolder = new Rectangle(20, 730, 120, 830);

        // Create Matrix object
        Matrix matrix = new Matrix(new double[] {
            _logoPlaceHolder.getURX() - _logoPlaceHolder.getLLX(), 0, 0,
            _logoPlaceHolder.getURY() - _logoPlaceHolder.getLLY(),
            _logoPlaceHolder.getLLX(), _logoPlaceHolder.getLLY() });

        // Using ConcatenateMatrix (concatenate matrix) operator: defines how image must be placed
        page.getContents().add(new ConcatenateMatrix(matrix));
        XImage ximage = page.getResources().getImages().get_Item(page.getResources().getImages().size());
        // Using Do operator: this operator draws image
        page.getContents().add(new Do(ximage.getName()));
        // Using GRestore operator: this operator restores graphics state
        page.getContents().add(new GRestore());

        // -------------------------------------------------------------
        // Add Header
        TextFragment header = new TextFragment("New ferry routes in Fall 2020");
        header.getTextState().setFont(FontRepository.findFont("Arial"));
        header.getTextState().setFontSize(24);
        header.setHorizontalAlignment (HorizontalAlignment.Center);
        header.setPosition(new Position(130, 720));
        page.getParagraphs().add(header);

        // Add description
        String descriptionText = "Visitors must buy tickets online and tickets are limited to 5,000 per day. Ferry service is operating at half capacity and on a reduced schedule. Expect lineups.";
        TextFragment description = new TextFragment(descriptionText);
        description.getTextState().setFont(FontRepository.findFont("Times New Roman"));
        description.getTextState().setFontSize(14);
        description.setHorizontalAlignment(HorizontalAlignment.Left);
        page.getParagraphs().add(description);


        // Add table
        Table table = new Table();
        table.setColumnWidths("200");
        table.setBorder(new BorderInfo(BorderSide.Box, 1f, Color.getDarkSlateGray()));
        table.setDefaultCellBorder(new BorderInfo(BorderSide.Box, 0.5f, Color.getBlack()));
        table.getMargin().setBottom(10);
        table.getDefaultCellTextState().setFont(FontRepository.findFont("Helvetica"));

        Row headerRow = table.getRows().add();
        headerRow.getCells().add("Departs City");
        headerRow.getCells().add("Departs Island");

        for (Cell headerRowCell : headerRow.getCells())
        {
            headerRowCell.setBackgroundColor(Color.getGray());
            headerRowCell.getDefaultCellTextState().setForegroundColor(Color.getWhiteSmoke());
        }

        LocalTime time = LocalTime.of(6,0);
        Duration incTime = Duration.ofMinutes(30);

        for (int i = 0; i < 10; i++)
        {
            Row dataRow = table.getRows().add();
            dataRow.getCells().add(time.toString());
            time=time.plus(incTime);
            dataRow.getCells().add(time.toString());
        }

        page.getParagraphs().add(table);

        document.save(Paths.get(_dataDir.toString(), "Complex.pdf").toString());
    }

}