使用apache common exec写入pdf

import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.ExecuteException;
import org.apache.commons.exec.ExecuteResultHandler;
import org.apache.commons.exec.ExecuteStreamHandler;
import org.apache.commons.exec.PumpStreamHandler;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;

public class PdfWriter {

    public static void main(String[] args) {
        String inputText = "Hello, World!";
        String outputPdfPath = "output.pdf";

        try {
            // 创建命令行对象
            CommandLine commandLine = new CommandLine("pdftk");
            commandLine.addArgument("input.pdf");
            commandLine.addArgument("output");
            commandLine.addArgument(outputPdfPath);
            commandLine.addArgument("background");
            commandLine.addArgument("-");
            commandLine.addArgument("stamp");
            commandLine.addArgument("input.pdf");

            // 创建执行器对象
            DefaultExecutor executor = new DefaultExecutor();

            // 设置输入流
            executor.setStreamHandler(new PumpStreamHandler(System.in));

            // 执行命令行程序
            executor.execute(commandLine);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}