elasticsearch中的高亮问题

我用Java去实现，每次都只能输出一条高亮结果，后面的都为空，请问该怎么解决
for(SearchHit hit : hits){

Map result = hit.highlightFields();

System.out.println("result:" + result);

HighlightField titleField = result.get("title");

Text[] titleTexts = titleField.fragments();

        for(Text text : titleTexts){  
            System.out.println("title text: "+text);  
        }  
    }  

http://www.cnblogs.com/liuhai35/p/6090702.html