使用java操作 ppt转图片

提示异常如下：
[08-19 16:16:29]-[main]-[INFO]-[Icepdf.java][44]-start document convert......
接收的参数：{"scale":2,"user":"test","file_id":"123456789","filepath":"http://ufile.yl1001.com/uploads/gongwen/2017-07-21/1500619518-92huo52.pptx"}
后缀 :pptx 长度为：4
[08-19 16:16:29]-[main]-[INFO]-[Icepdf.java][85]-The picture local location is ./data/img/2017-08-19/1500619518-92huo52/
[08-19 16:16:29]-[main]-[INFO]-[Icepdf.java][94]-The picture accurate location is http://ufile.yl1001.com/img/2017-08-19/1500619518-92huo52/
[08-19 16:16:29]-[main]-[INFO]-[Icepdf.java][105]-It takes 635 ms to download the document
第0页。第1页。第2页。第3页。第4页。第5页。第6页。第7页。第8页。第9页。第10页。第11页。第12页。第13页。第14页。第15页。第16页。第17页。第18页。第19页。第20页。第21页。Exception in thread "main" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at org.apache.poi.xslf.usermodel.RenderableShape.createRadialGradientPaint(RenderableShape.java:312)
at org.apache.poi.xslf.usermodel.RenderableShape.selectPaint(RenderableShape.java:127)
at org.apache.poi.xslf.usermodel.RenderableShape.getPaint(RenderableShape.java:336)
at org.apache.poi.xslf.usermodel.RenderableShape$4.fetch(RenderableShape.java:356)
at org.apache.poi.xslf.usermodel.XSLFSimpleShape.fetchShapeProperty(XSLFSimpleShape.java:564)
at org.apache.poi.xslf.usermodel.RenderableShape.getFillPaint(RenderableShape.java:364)
at org.apache.poi.xslf.usermodel.RenderableShape.render(RenderableShape.java:520)
at org.apache.poi.xslf.usermodel.XSLFSimpleShape.draw(XSLFSimpleShape.java:534)
at org.apache.poi.xslf.usermodel.XSLFSheet.draw(XSLFSheet.java:506)
at org.apache.poi.xslf.usermodel.XSLFSlide.draw(XSLFSlide.java:220)
at com.elan.utils.FileConvert.PDForPPT2img(FileConvert.java:168)
at com.elan.test.Icepdf.pdf2Pic(Icepdf.java:109)
at com.elan.test.Icepdf.main(Icepdf.java:138)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.apache.poi.xslf.usermodel.RenderableShape.createRadialGradientPaint(RenderableShape.java:305)
... 12 more
Caused by: java.lang.IllegalArgumentException: Keyframe fractions must be increasing: 0.6
at java.awt.MultipleGradientPaint.(Unknown Source)
at java.awt.RadialGradientPaint.(Unknown Source)
at java.awt.RadialGradientPaint.(Unknown Source)
at java.awt.RadialGradientPaint.(Unknown Source)
... 17 more