Most dissertations of China HowNet are only downloaded in CAJ format, and can only be opened by software provided by HowNet, such as CAJViewer, which brings inconvenience to the reading and management of documents and is unfriendly to many users who use non-Windows systems.
However, if the CAJ file is converted into a PDF file by using the printing function of CajViewer, the obtained files are all pictures, and words cannot be selected, and the outline list of the original document will also be lost. In order to solve the above two problems, Firefly introduced the function module of Caj to PDF.