itext合并pdf文件

1. maven库增加依赖

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.10</version>
</dependency>

2. 合并代码

/**
 * 合并原pdf为新文件
 *
 * @param files   pdf绝对路径集合
 * @param newfile 新pdf绝对路径
 * @return
 * @throws IOException
 * @throws DocumentException
 */
public static void mergePdfFiles(List<String> files, String newfile) throws IOException, DocumentException {
	// 合并的pdf每页都按照第一个pdf的尺寸大小
    com.itextpdf.text.Document document = new com.itextpdf.text.Document(new PdfReader(files.get(0)).getPageSize(1));
    PdfCopy copy = new PdfCopy(document, new FileOutputStream(newfile));
    document.open();
    for (int i = 0; i < files.size(); i++) {
        PdfReader reader = new PdfReader(files.get(i));
        int n = reader.getNumberOfPages();
        for (int j = 1; j <= n; j++) {
            document.newPage();
            PdfImportedPage page = copy.getImportedPage(reader, j);
            copy.addPage(page);
        }
    }
    document.close();
}