关于java文档合并的问题

java文档合并的问题如下，如果不加下面这句话，

里面内容的时候，前两页输出的是XWPFRun里面输出的内容，加了后前两页就百变成文档里的内容了，求帮助

for (int i = 0; i < scword.size(); i++) {
                in = new FileInputStream(scword.get(i).getPath());
                OPCPackage open = OPCPackage.open(in);
                XWPFDocument document = new XWPFDocument(open);
                if(i==0){
                    for(int j = 0;j < target.size(); j++){
                        ins = new FileInputStream(target.get(i).getPath());
                        OPCPackage open1 = OPCPackage.open(ins);
                        XWPFDocument document1 = new XWPFDocument(open1);
                        documentlist.add(document1);
                    }
                }
                documentlist.add(document);
            }
            for (int i = 0; i < documentlist.size(); i++) {
              //获取第一个值，并不能为空,，会出错    
              switch (i) {
                    case 0:
                        if (!tname.isEmpty()){
                            doc=new XWPFDocument();
                            XWPFParagraph paragraphX = doc.createParagraph();
                            XWPFRun runX = paragraphX.createRun();
                            runX.setText(tname);
                            runX.setBold(false);//加粗
                            runX.setFontSize(14);    
                            documentlist.get(i).createParagraph().setPageBreak(true);        
                            doc.createParagraph().setPageBreak(true);
                        }
                        break;
                    case 1:
                        if (!fword.isEmpty()) {
                            for (String sc : fword) {
                                XWPFParagraph paragraph = doc.createParagraph();
                                XWPFRun run = paragraph.createRun();
                                run.setText(sc);
                                documentlist.get(i).createParagraph().setPageBreak(true);
                            }
                        }
                        break;
                    case 2:
                         doc= documentlist.get(2);
                         doc.createParagraph().setPageBreak(true);
                         break;
                    default:
                        documentlist.get(i).createParagraph().setPageBreak(true);
                        appendBody(doc, documentlist.get(i));
                        break;
                }       
            }
            // 分页
            doc.createParagraph().setPageBreak(true);
            doc.write(dest);    

if(i==0){for(){documentlist.add(document1);}} 这不就是相当于在最前面插入数据么，自然前面的是就是文档里的内容了