如何使用iTextPdf绘制同一文档的两个JFreeCharts

Document document = new Document();

PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream("output.pdf"));

document.open();

document.setPageSize(PageSize.A4);
document.setMargins(50, 50, 50, 50);
document.newPage();

JFreeChart chart1 = // 生成第一个图表的代码
PdfContentByte contentByte1 = writer.getDirectContent();
PdfTemplate template1 = contentByte1.createTemplate(500, 400);
Graphics2D graphics2D1 = template1.createGraphics(500, 400);
chart1.draw(graphics2D1, new Rectangle2D.Double(0, 0, 500, 400));
graphics2D1.dispose();
contentByte1.addTemplate(template1, 50, 50);

document.newPage();
JFreeChart chart2 = // 生成第二个图表的代码
PdfContentByte contentByte2 = writer.getDirectContent();
PdfTemplate template2 = contentByte2.createTemplate(500, 400);
Graphics2D graphics2D2 = template2.createGraphics(500, 400);
chart2.draw(graphics2D2, new Rectangle2D.Double(0, 0, 500, 400));
graphics2D2.dispose();
contentByte2.addTemplate(template2, 50, 50);

document.close();