Error opening data file /Users/lanxiaoshan_wangjie/Library/Developer/CoreSimulator/Devices/BA361244-0102-4DF9-A59E-D84CBAF9CD2D/data/Containers/Bundle/Application/12A84A7C-016D-4A04-BB90-7416E578F01E/ocrTestProject.app/tessdata/eng.traineddata
这个问题搞了一上午，也没搞出来，最后终于恍然大悟，原来没有在资源文件中加入tessdata这个库文件，如下图，加入即可。
Error opening data file /Users/lanxiaoshan_wangjie/Library/Developer/CoreSimulator/Devices/BA361244-0102-4DF9-A59E-D84CBAF9CD2D/data/Containers/Bundle/Application/12A84A7C-016D-4A04-BB90-7416E578F01E/ocrTestProject.app/tessdata/eng.traineddata
Please make sure the TESSDATA_PREFIX environment variable is set to the parent directory of your "tessdata" directory.
Failed loading language 'eng'
Tesseract couldn't load any languages!
2017-10-29 14:44:41.084553+0800 ocrTestProject[5639:2608445] (null)
