Itext 生成pdf 表格嵌套的时候，内表格与外表格上下有间隙

Itext 生成pdf 表格嵌套的时候，内表格与外表格上下有间隙      我不知道有什么好的处理办法，大家帮帮忙
public void createPDF(HttpServletResponse response) {
  
   Document document = new Document();
   StringBuffer script = new StringBuffer();
      script.append("this.print({bUI: false,bSilent: true,bShrinkToFit: false});") 
      .append("\r\nthis.closeDoc();");
   document.setPageSize(PageSize.A4);
  
   try {
BaseFont bfChinese = BaseFont.createFont("STSong-Light","UniGB-UCS2-H", BaseFont.NOT_EMBEDDED);// 设置中文字体
    Font headFont0 = new Font(bfChinese, 10);
    ByteArrayOutputStream ops = new ByteArrayOutputStream();
      
    PdfWriter pdfwriter =  PdfWriter.getInstance(document,ops);
    document.open();
   // pdfwriter.addJavaScript(script.toString());
    pdfwriter.setViewerPreferences(PdfWriter.PageModeUseThumbs);
    float[] widths = {474f};
    float[] width1 = {74f,80f,20f,40f,20f,40f,20f,180f};
    float[] width2 = {74f,170f,80f,150f};
    float[] width3 = {74f,400f};
    float[] width4 = {158f,158f,158f};
    float[] width5 = {316f,158f};
    PdfPTable table = new PdfPTable(widths);
    table.setSpacingBefore(130f);// 设置表格上面空白宽度
    table.setTotalWidth(474);
    table.setLockedWidth(true);// 设置表格的宽度固定
    table.setWidthPercentage(100f);
    PdfPTable pt = null;
    PdfPCell cell = null;
 //1=====         
    cell = new PdfPCell(new Paragraph("", headFont0));
    pt = this.createTable(width1, 0f, 474f, true);
    cell.setBorderWidth(0.1f);
    cell.setFixedHeight(14);
    pt.addCell(cell);
            pt.addCell(cell);
            pt.addCell(cell);
            pt.addCell(cell);
            pt.addCell(cell);
            pt.addCell(cell);
            pt.addCell(cell);
            pt.addCell(cell);
    table.addCell(pt);
  
 //2=====         
    pt = this.createTable(width2, 0f, 474f, true);
    cell.setFixedHeight(14);
            pt.addCell(cell);
            pt.addCell(cell);
            pt.addCell(cell);
            pt.addCell(cell);
            table.addCell(pt);
 //3=====               
            pt = this.createTable(width3, 0f, 474f, true);
            pt.addCell(cell);
            pt.addCell(cell);
            table.addCell(pt);
 //4=====           
            pt = this.createTable(width4, 0f, 474f, true);
            pt.addCell(cell);
            pt.addCell(cell);
            pt.addCell(cell);
            table.addCell(pt);
            
//5=====           
            pt = this.createTable(width4, 0f, 474f, true);
            cell.setFixedHeight(100);
            pt.addCell(cell);
            pt.addCell(cell);
            pt.addCell(cell);
            table.addCell(pt);
            
 //6=====             
            pt = this.createTable(width5, 0f, 474f, true);
            cell.setFixedHeight(14);
            pt.addCell(cell);
            pt.addCell(cell);
            table.addCell(pt);
            
 //7=====             
            cell = new PdfPCell(new Paragraph("", headFont0));
            cell.setFixedHeight(14);
            table.addCell(cell);
            
 //8=====             
            pt = this.createTable(width5, 0f, 474f, true);
            cell.setFixedHeight(14);
            pt.addCell(cell);
            pt.addCell(cell);
            table.addCell(pt);
            
            document.add(table);
    document.close();

    response.setContentType("application/pdf");
    response.setContentLength(ops.size());
    ServletOutputStream out = response.getOutputStream();
    ops.writeTo(out);
    ops.write(1);
    out.flush();
    //end 
   
   } catch (DocumentException de) {
    System.err.println(de.getMessage());
 
   } catch (IOException ioe) {
    System.err.println(ioe.getMessage());
    
   }

}

public PdfPTable createTable(float[] f,float spacingBefore,float totalWidth,boolean lockedWidth){
    PdfPTable table = new PdfPTable(f);
    table.setSpacingBefore(spacingBefore);
    table.setTotalWidth(totalWidth);
    table.setLockedWidth(true);
    return table;
}


}