I solve it like that but it is just run for word document any suggestion how can i use it to merge with pdf excel and picture ?
public void mergeDocx(InputStream s1, InputStream s2, OutputStream os) throws Exception {
WordprocessingMLPackage target = WordprocessingMLPackage.load(s1);
insertDocx(target.getMainDocumentPart(), IOUtils.toByteArray(s2));
SaveToZipFile saver = new SaveToZipFile(target);
saver.save(os);
}
private static void insertDocx(MainDocumentPart main, byte[] bytes) throws Exception {
AlternativeFormatInputPart afiPart = new AlternativeFormatInputPart(new PartName("/part" + (chunk) + ".docx"));
afiPart.setContentType(new ContentType(CONTENT_TYPE));
afiPart.setBinaryData(bytes);
Relationship altChunkRel = main.addTargetPart(afiPart);
CTAltChunk chunk = Context.getWmlObjectFactory().createCTAltChunk();
chunk.setId(altChunkRel.getId());
main.getContent().add(1,chunk);
// i add this method
```