*, pdf reading of java
pdfbox does not support Chinese well, xpdf is better but cannot achieve cross-system development But the current situation is: Pdfbox can read the content of Chinese documents containing pictures, so can it continue to be used? Ha ha eg:https://blog.csdn.net/fangyuandoit/article/details/78558284?locationNum=4&fps=1
*, java word reading
It can be implemented using poi, one of which is the 93 version of the jar is the scratchpad package eg: https://www.cnblogs.com/Renyi-Fan/p/8147650.html
*, rtf reading of java
Refer to the word implementation of java
*, Excel read in java
can be achieved using poi eg:https://blog.csdn.net/ArryLuo123/article/details/72639220
*, PPT reading of java
can be achieved using poi eg https://www.cnblogs.com/dingjiaoyang/p/6111484.html-pptx https://www.cnblogs.com/firstdream/p/8137565.html-ppt