jasperreports中如何填补细节区域中的空白行

最近一直在学习jasperreports，看过 jasperreport  ultimate guide 1.2.5后，会了一般的使用，不过，还是碰到不少问题
1）在detail中画线，大家应该都用过，不过会出现下图中的问题
通过阅读代码，找到了一个解决办法
JRHorizontalFiller，水平添加实现
1）修改fillDetail

java 代码

private void fillDetail() throws JRException {
     JRFillBand tmp = detail;
     if (log.isDebugEnabled() && !detail.isEmpty()) {
         log.debug("Fill " + fillerId + ": detail");
     }

     if (!detail.isPrintWhenExpressionNull()) {
         calculator.estimateVariables();
         detail.evaluatePrintWhenExpression(JRExpression.EVALUATION_ESTIMATED);
     }

     if (detail.isToPrint()) {
         while (
                 (columnIndex == columnCount - 1 || isNewGroup)
                         && detail.getHeight() > columnFooterOffsetY - offsetY
                 ) {判断什么时间断页
             //在断页前，填充细节区域中的空白行
             fillDetailBlankBand(tmp, JRExpression.EVALUATION_DEFAULT, false, columnFooterOffsetY - offsetY,offsetY);
             byte evalPrevPage = (isNewGroup ? JRExpression.EVALUATION_DEFAULT : JRExpression.EVALUATION_OLD);

             fillPageBreak(
                     false,
                     evalPrevPage,
                     JRExpression.EVALUATION_DEFAULT,
                     true
             );
         }
     }

     scriptlet.callBeforeDetailEval();
     calculator.calculateVariables();
     scriptlet.callAfterDetailEval();

     if (!detail.isPrintWhenExpressionNull()) {
         detail.evaluatePrintWhenExpression(JRExpression.EVALUATION_DEFAULT);
     }

     if (detail.isToPrint()) {
         if (
                 offsetX == lastDetailOffsetX
                         && offsetY == lastDetailOffsetY
                 ) {
             if (columnIndex == columnCount - 1) {
                 setFirstColumn();
             } else {
                 columnIndex++;
                 offsetX += columnWidth + columnSpacing;
                 offsetY -= detail.getHeight();

                 setColumnNumberVariable();
             }
         }

         fillFixedBand(detail, JRExpression.EVALUATION_DEFAULT, false);

         lastDetailOffsetX = offsetX;
         lastDetailOffsetY = offsetY;
     }

     isNewPage = false;
     isNewColumn = false;
     isNewGroup = false;
 }

2）修改fillPageFooter

java 代码

private void fillPageFooter(byte evaluation) throws JRException {
       JRFillBand crtPageFooter = getCurrentPageFooter();

       if (log.isDebugEnabled() && !crtPageFooter.isEmpty()) {
           log.debug("Fill " + fillerId + ": " + (isLastPageFooter ? "last " : "") + "page footer");
       }

       offsetX = leftMargin;

       if (!isSubreport() && !fillContext.isIgnorePagination()) {
           offsetY = pageHeight - crtPageFooter.getHeight() - bottomMargin;
       }

       crtPageFooter.evaluatePrintWhenExpression(evaluation);

       if (crtPageFooter.isToPrint()) {
           //填充细节区域中的空白行
          fillDetailBlankBand(detail, evaluation, true, columnFooterOffsetY - lastDetailOffsetY,lastDetailOffsetY);
           fillFixedBand(crtPageFooter, evaluation);
       }
   }

3）添加 fillDetailBlankBand

java 代码

protected void fillDetailBlankBand(JRFillBand band, byte evaluation, boolean allowShrinking, int stretchHeight, int _offsetY) throws JRException {
       JRPrintBand printBand = band.fill(stretchHeight);
       printBand.setHeight(stretchHeight);
       JRPrintElement printElement = null;
       JRElement[] fillElements = band.getElements();
       for (int i = 0; i < fillElements.length; i++) {
           JRFillElement fillElement = (JRFillElement) fillElements[i];
           if (fillElement instanceof JRFillTextField) {
               JRFillTextField fillFieldElement = (JRFillTextField) fillElement;
               fillFieldElement.rewind();
               fillFieldElement.setRawText("");
               printElement = fillFieldElement.fill();
               printElement.setHeight(stretchHeight);
               printElement.setX(printElement.getX() + offsetX);
               printElement.setY(printElement.getY() + _offsetY);
               printPage.addElement(printElement);
               //  printBand.addElement(printElement);
           }
       }
       resolveBandBoundElements(band, evaluation);
   }

通过以上步骤就解决了这个问题