Apache tika 可以解析各种富文本格式的文件，得到其中的文本内容字符串。如tika 可用于解析Office 97/2003/2007 格式、PDF 格式、HTML 等格式的文件。请参考tika-app-1.5.jar 的功能，实现一个GUI 界面的桌面程序，该程序可以打开以上几种格式的文件，调用tika 进行解析，在界面上展示txt 解析结果，并将结果保存成文本文件。该程序也可以同时打开一组文件，以多线程的方式对它们进行并行处理。注：请在程序中导入tika-core-1.5.jar 和tika-parsers-1.5.jar 来调用tika的功能（也可以只导入tika-app-1.5.jar）。-Tika Apache can parse a variety of rich text format file, get the text content of the string. Such as Tika can be used to parse 97/2003/2007 Office format, PDF format, HTML format file. Please refer to the tika-app-1.5.jar function, to achieve a GUI interface of the desktop program, the program can open more than a few formats of the file, call Tika to resolve, in the interface to display the results of TXT analysis, and save the results into a text file. The program can also open a group of files at the same time, in order to carry out the process of multi thread parallel processing. Note: import tika-core-1.5.jar and tika-parsers-1.5.jar in the program to call the Tika function (also can only import tika-app-1.5.jar).