如何从 Java 应用程序动态生成 PDF 文件

IronPDF。

IronPDF Java Library is the most popular Java PDF library developed by Iron Software for creating PDFs, editing new files, and manipulating existing PDFs. It is designed to be compatible with a wide range of JVM languages, including Java, Scala, and Kotlin, and it can run on a wide range of platforms, including Windows, Linux, Docker, Azure, and AWS. IronPDF works with popular IDEs such as IntelliJ IDEA and Eclipse.

The main features include the ability to create a PDF file from HTML, HTTP, JavaScript, CSS, XML documents, and various image formats. In addition, IronPDF offers the abilities to add headers and footers, create tables in PDF, add digital signatures, attachments, implement passwords, and security features. It supports complete multithreading and so much more!

Now, let's begin with the code examples for creating dynamic documents.

First of all, create a new Maven repository project.

创建一个新的Java项目

For demonstration purposes, this tutorial will use IntelliJ IDE. You can use an IDE of your choice. Steps for creating a new Java project may differ from IDE to IDE. Use the following steps:

1. Launch the IntelliJ IDE.
2. Select File > New > Project.
3. Enter Project Title.
4. Choose a location, a language, a build system, and a JDK.
5. Click the Create button.

Create a Project

Name your project, choose a location, a language, a build system, and a JDK, then select the Create button option. A new project will be created.

Now, install IronPDF in this demo Java application.

Install IronPDF Java Library

The next step is to add a dependency in the pom.xml file for installing IronPDF. Add the following XML source code in the pom.xml file as shown below.

<!-- Add IronPDF to your Maven Project -->
<dependency>
    <groupId>com.ironsoftware</groupId>
    <artifactId>ironpdf</artifactId>
    <version>INSERT_LATEST_VERSION_HERE</version>
</dependency>

<!-- Add IronPDF to your Maven Project -->
<dependency>
    <groupId>com.ironsoftware</groupId>
    <artifactId>ironpdf</artifactId>
    <version>INSERT_LATEST_VERSION_HERE</version>
</dependency>

Replace INSERT_LATEST_VERSION_HERE with the latest version of IronPDF from the Maven repository.

After adding the dependency, build the project. The application will automatically install the library from the Maven repository.

Let's begin with a straightforward example of converting an HTML string into a PDF file.

Create PDF Documents

在此示例中，IronPDF用于将HTML内容渲染为PDF文档，然后保存到指定位置。

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;
import java.nio.file.Paths;

public class HtmlToPdfExample {

    public static void main(String[] args) {
        // Define HTML content
        String htmlString = "<h1>My First PDF File</h1><p>This is a sample PDF file</p>";

        // Convert HTML content to PDF
        PdfDocument myPdf = PdfDocument.renderHtmlAsPdf(htmlString);

        // Save the PdfDocument to a file
        try {
            myPdf.saveAs(Paths.get("myPDF.pdf"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;
import java.nio.file.Paths;

public class HtmlToPdfExample {

    public static void main(String[] args) {
        // Define HTML content
        String htmlString = "<h1>My First PDF File</h1><p>This is a sample PDF file</p>";

        // Convert HTML content to PDF
        PdfDocument myPdf = PdfDocument.renderHtmlAsPdf(htmlString);

        // Save the PdfDocument to a file
        try {
            myPdf.saveAs(Paths.get("myPDF.pdf"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In the above function, the HTML content is assigned to a string variable. The renderHtmlAsPdf method takes a string as an argument and converts HTML content into a PDF document instance. The saveAs method accepts the location path as an input and saves the instance of the PDF file in the selected directory.

The PDF produced by the aforementioned code is shown below.

输出

Generate PDF File from HTML File

IronPDF also provides the amazing functionality of generating PDF files from HTML files.

The sample HTML file that will be used in the example is shown below.

Rendered HTML with new paragraph

The following is the sample code snippet for generating PDFs:

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;

public class HtmlFileToPdfExample {

    public static void main(String[] args) {
        // Convert HTML file to PDF
        PdfDocument myPdf = PdfDocument.renderHtmlFileAsPdf("myFile.html");

        // Save the PdfDocument to a file
        try {
            myPdf.saveAs("myPDF.pdf");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;

public class HtmlFileToPdfExample {

    public static void main(String[] args) {
        // Convert HTML file to PDF
        PdfDocument myPdf = PdfDocument.renderHtmlFileAsPdf("myFile.html");

        // Save the PdfDocument to a file
        try {
            myPdf.saveAs("myPDF.pdf");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

The renderHtmlFileAsPdf method accepts the path to the HTML file as an argument and produces a PDF document from the HTML file. This PDF file is afterward saved using the saveAs method to a local drive.

The document that this program generated in PDF format is shown below.

PDF 输出

The next step is to use a sizable HTML document that contains JavaScript and CSS and check the accuracy and consistency of the design as it converts HTML to PDF.

Generate PDF files from HTML files

The following sample HTML page will be used and it includes images, animation, styling, jQuery, and Bootstrap.

Sample HTML Page

Sample HTML

The sample HTML document shows that it has extensive styling and includes graphics. This HTML file will be converted into a PDF document, and the accuracy of the content and styling will be evaluated.

The same line of code from the example above will be used.

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;

public class StyledHtmlToPdfExample {

    public static void main(String[] args) {
        // Convert HTML file with styling to PDF
        PdfDocument myPdf = PdfDocument.renderHtmlFileAsPdf("index.html");

        // Save the PdfDocument to a file
        try {
            myPdf.saveAs("styledPDF.pdf");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;

public class StyledHtmlToPdfExample {

    public static void main(String[] args) {
        // Convert HTML file with styling to PDF
        PdfDocument myPdf = PdfDocument.renderHtmlFileAsPdf("index.html");

        // Save the PdfDocument to a file
        try {
            myPdf.saveAs("styledPDF.pdf");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

The previous example already includes a code explanation. The rest is unchanged;

This is the output PDF file:

HTML to PDF

Using IronPDF to create PDF files is quite simple. The source document's format and content are both consistent.

A URL can also be used to create a PDF file.

Convert URL to PDF document

The following code sample will generate a PDF file from a URL.

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;

public class UrlToPdfExample {

    public static void main(String[] args) {
        // Convert URL to PDF
        PdfDocument myPdf = PdfDocument.renderUrlAsPdf("https://en.wikipedia.org/wiki/PDF");

        // Save the PdfDocument to a file
        try {
            myPdf.saveAs("urlPDF.pdf");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import com.ironsoftware.ironpdf.PdfDocument;
import java.io.IOException;

public class UrlToPdfExample {

    public static void main(String[] args) {
        // Convert URL to PDF
        PdfDocument myPdf = PdfDocument.renderUrlAsPdf("https://en.wikipedia.org/wiki/PDF");

        // Save the PdfDocument to a file
        try {
            myPdf.saveAs("urlPDF.pdf");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

The renderUrlAsPdf function accepts a URL as an argument and converts it to a PDF document. This PDF document is later saved to a local drive using the saveAs function.

The following is the output PDF:

输出 PDF

It is also possible to add a watermark, header, footer, digital signature, convert XML files/JSP pages, and more.

The next step is to generate password-protected PDFs.

Generate Password-protected PDF File

The following sample code demonstrates the example of adding security to the generated PDF file.

import com.ironsoftware.ironpdf.PdfDocument;
import com.ironsoftware.ironpdf.security.PdfEditSecurity;
import com.ironsoftware.ironpdf.security.PdfPrintSecurity;
import com.ironsoftware.ironpdf.security.SecurityOptions;
import java.io.IOException;
import java.nio.file.Paths;

public class SecurePdfExample {

    public static void main(String[] args) {
        // Load an existing PDF document
        PdfDocument myPdf = PdfDocument.fromFile(Paths.get("myPDF.pdf"));

        // Configure security options
        SecurityOptions securityOptions = new SecurityOptions();
        securityOptions.setAllowUserEdits(PdfEditSecurity.NO_EDIT);
        securityOptions.setAllowUserAnnotations(false);
        securityOptions.setAllowUserPrinting(PdfPrintSecurity.NO_PRINT);
        securityOptions.setAllowUserFormData(false);
        securityOptions.setOwnerPassword("123456"); // Set owner password
        securityOptions.setUserPassword("123412"); // Set user password

        // Apply security options to the PDF document
        myPdf.applySecurity(securityOptions);

        // Save the secured PdfDocument to a file
        try {
            myPdf.saveAs(Paths.get("securedPDF.pdf"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import com.ironsoftware.ironpdf.PdfDocument;
import com.ironsoftware.ironpdf.security.PdfEditSecurity;
import com.ironsoftware.ironpdf.security.PdfPrintSecurity;
import com.ironsoftware.ironpdf.security.SecurityOptions;
import java.io.IOException;
import java.nio.file.Paths;

public class SecurePdfExample {

    public static void main(String[] args) {
        // Load an existing PDF document
        PdfDocument myPdf = PdfDocument.fromFile(Paths.get("myPDF.pdf"));

        // Configure security options
        SecurityOptions securityOptions = new SecurityOptions();
        securityOptions.setAllowUserEdits(PdfEditSecurity.NO_EDIT);
        securityOptions.setAllowUserAnnotations(false);
        securityOptions.setAllowUserPrinting(PdfPrintSecurity.NO_PRINT);
        securityOptions.setAllowUserFormData(false);
        securityOptions.setOwnerPassword("123456"); // Set owner password
        securityOptions.setUserPassword("123412"); // Set user password

        // Apply security options to the PDF document
        myPdf.applySecurity(securityOptions);

        // Save the secured PdfDocument to a file
        try {
            myPdf.saveAs(Paths.get("securedPDF.pdf"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

The PDF file is made read-only by the above code, and edits or paragraph alignment are not allowed. The document is also restricted from printing, ensuring it cannot be printed. A password has also been set. The file is now very secure. In this way, different file permissions can be defined, and dynamic output can be generated using IronPDF.

摘要

This tutorial demonstrated how to generate PDF files. A PDF file was created from an HTML string, an HTML file, and a URL, with examples ranging from simple to complex. Many more useful features are available such as adding a watermark, footer, header, foreground color, merging and splitting pages, etc. All of them cannot be covered here; visit the IronPDF Official Documentation for further exploration.

HTML to PDF conversion was made a breeze by IronPDF. HTML was converted to PDF with just one line of code. Some security measures have also been added to the PDF file. It's faster, more accurate, and safer. Each generated PDF includes the IronPDF watermark. This is due to the fact that a free development version with limited permissions is being used, not the commercial license. It can be gotten rid of by purchasing a free trial version or a full license as needed.