这是一个基于jfreechart的饼图程序，主要特点是不在服务器端生成图片文件，直接在用户端显示图片，解决了大量用户访问时造成的写文件冲突，另外可减轻服务器的负荷-based jfreechart pie procedures, the main characteristic is not server-generated image files, directly in the client showed photographs, addressed many users visit the written document conflict, and reduce server load