First we need to create a Highlighter instance;
Highlighter hl = new Highlighter(new SimpleHTMLFormatter("<font color=\"red\" font-size=\"14px\">","</font>"),new QueryScorer(query));
Use GetBestFragment method get the result
row["Name"] = hl.GetBestFragment(sa,"Name",doc.Get("Name"));
row["Introduce"] = hl.GetBestFragment(sa,"Introduce",doc.Get("Introduce"));
row["Introduce"] = hl.GetBestFragment(sa,"Introduce",doc.Get("Introduce"));
row this is a table row