tess4j 设置只识别数字和字母

sen*_*enz 1 java ocr tess4j

我想设置tess4j为只识别数字和字母

Tesseract instance = new Tesseract();
instance.setDatapath("C:\\Users\\qyw\\Desktop\\tessdata");
String s = instance.doOCR(img);
System.out.println(s);
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ngu*_*enq 6

instance.setTessVariable("tessedit_char_whitelist", "0123456789abcdefghijklmnopqrstuvwxyz");
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