关于JFreeChart生成3D饼图

用JFreeChart生成3D饼图怎么能让每块之间分离呀？DefaultPieDataset dataset = new DefaultPieDataset();
        ReportService service = ServiceLoader.getReportService();
List<Report> list = service.getSexRatio(endDate);
for (Report item : list) {
            if(!"合计".equals(item.getString("NAME",""))) {
                dataset.setValue(item.getString("NAME",""),item.getInteger("TOTAL",0));
            }
}        chart = ChartFactory.createPieChart3D("总人数性别结构比", dataset, true, true, false);
        PiePlot pieplot = (PiePlot)chart.getPlot();
        pieplot.setLabelFont(new Font("宋体", 0, 12));
        pieplot.setNoDataMessage("无数据");
        pieplot.setCircular(true);
                //设置标签距离
        pieplot.setLabelGap(0.02D);        //设置图片透明度
        pieplot.setForegroundAlpha(0.5f);        pieplot.setBackgroundPaint(new Color(199,237,204));
                pieplot.setLabelGenerator(new StandardPieSectionLabelGenerator(
                "{0} {2}",
                NumberFormat.getNumberInstance(),
                new DecimalFormat("0.00%")));