pdf merger

For some reason the need for pdf merge, but most of the Internet can only merge two or three, and there are restrictions, 求人不如求己, wrote a reference on the Internet wrote a utility class.

We are using the apache pdf processing tools.

maven:

 <dependency>
      <groupId>org.apache.pdfbox</groupId>
      <artifactId>pdfbox</artifactId>
      <version>2.0.15</version>
 </dependency>

Code:

public class PdfUtil {

    //获取某个目录下的所有文件
    private static String[] getFiles(String folder){
        File _folder = new File(folder);
        String[] filesInFolder;

        if(_folder.isDirectory()){
            filesInFolder = _folder.list();
            return filesInFolder;
        } else {
            filesInFolder = new String[1];
            filesInFolder[1] = folder;
            return filesInFolder;
        }
    }
    
    //合并pdf, folder 为文件夹，destinationFileName为目标文件
    public static void generatePdf(String folder, String destinationFileName) throws Exception{
        //pdf合并工具类
        PDFMergerUtility mergePdf = new PDFMergerUtility();

        String[] filesInFolder = getFiles(folder);

        for(int i = 0; i < filesInFolder.length; i++){
            //循环添加要合并的pdf存放的路径
            mergePdf.addSource(folder + File.separator + filesInFolder[i]);
        }
        //设置合并生成pdf文件名称
        mergePdf.setDestinationFileName(folder + File.separator + destinationFileName);
        //合并pdf

        mergePdf.mergeDocuments();
        System.out.println("merge success");
    }

    public static void main(String[] args) throws Exception {
        String folder = "C:\\Users\\14518\\Desktop\\测试";
        String destinationFileName = "测试.pdf";
        generatePdf(folder,destinationFileName);
        System.out.println(args);
    }

If the contents of the folder in excess, it will be reported java.lang.OutOfMemoryError: Java heap space, namely a heap overflow.

Then only need to set the start-up parameters -Xms256M -Xmx512M, if it is given, then, can be adjusted according to the situation