Java uses lowagie to dynamically generate PDFs based on a template.

To dynamically generate PDFs using lowagie based on a template, you can follow these steps:

1. Firstly, you need to download the iText library jar file from the official website of lowagie, and then add it to the classpath of your Java project.
2. Create a Java class to generate PDF. You can use the following code as a starting point:

import com.lowagie.text.Document;
import com.lowagie.text.DocumentException;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfStamper;

import java.io.FileOutputStream;
import java.io.IOException;

public class PdfGenerator {
    public static void main(String[] args) {
        try {
            // 读取模板文件
            PdfReader reader = new PdfReader("template.pdf");
            // 创建输出文件
            FileOutputStream fileOutputStream = new FileOutputStream("output.pdf");
            // 创建PDF文档对象
            Document document = new Document();
            // 创建PDF写入器
            PdfStamper stamper = new PdfStamper(reader, fileOutputStream);
            
            // 在模板的指定位置插入动态内容
            // 使用AcroFields类可以获取模板中的表单域，然后根据需要设置内容
            // 例如：stamper.getAcroFields().setField("fieldName", "fieldValue");
            
            // 关闭PDF写入器和输出流
            stamper.close();
            fileOutputStream.close();
        } catch (IOException | DocumentException e) {
            e.printStackTrace();
        }
    }
}

1. In the code, you will need to use PdfReader to read the template file and then use PdfStamper to generate a new PDF file. You can use the AcroFields class to access the form fields in the template and set the content as needed.
2. Update the references to “template.pdf” and “output.pdf” in the code to your actual template file and output file paths.
3. Running the code will generate a new PDF file based on the template.

Please note that the lowagie library is no longer being maintained. We recommend using iText 7 to generate PDFs instead. iText 7 is the latest version of iText with more powerful features and easier usability.