jfreechart为1.0.12版本,用writeChartAsPNG、writeChartAsJPEG方法输出到浏览器,生成的图片另存为看到得都是保存为BMP格式选项,httplook工具抓取到得信息是:13746 bytes skipped. Reason: The content type is not captured(已经为writeChartAsPNG、writeChartAsJPEG的输出设置了content type :image/png 和 image/jpeg)坛子里有人曾说过设置输出的质量就可以解决,但我做的实验确都不能成功,请问是如何处理的?
response.reset();
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image/png");
ServletOutputStream output = response.getOutputStream();
......
ChartUtilities.writeChartAsPNG(output , chart, width , height,true,9);
response.reset();
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0); 就一切OK
有没有达人告诉我为什么?