java获取错误“montage.exe:无法创建临时文件“”：没有此类文件或目录@error/pdf.c/ReadPDFImage/476

Question

我正在使用ImageMagick-7.0.7-Q8和ghostscript（gs9.20）创建pdf文件的缩略图

调用“ProcessTask pt = montage.getProcessTask(op, (tag!=null)? (tag+":-") : "-" , "png:-");”时，我总是会出错

[Thumbnails] Process failed for 'TMP-2
000843':  montage.exe: unable to create temporary file '-': No such file or dire
ctory @ error/pdf.c/ReadPDFImage/476.; montage.exe:  `png:-' @ error/montage.c/M
ontageImageCommand/1775.;
org.im4java.core.CommandException: montage.exe: unable to create temporary file
'-': No such file or directory @ error/pdf.c/ReadPDFImage/476.
        at org.im4java.core.ImageCommand.finished(ImageCommand.java:253)
        at org.im4java.process.ProcessStarter.runAndNotify(ProcessStarter.java:3
67)
        at org.im4java.process.ProcessTask$1.run(ProcessTask.java:71)
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
        at java.util.concurrent.FutureTask.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)