Highlight

The key words entered by the user are displayed in red font in the title, which is the highlight commonly used in search.
Back end code:

private Map searchList(Map searchMap){//Created condition, used for query.
	Map map=new HashMap();//Create a Map object to return highlighted data
	HighlightQuery query=new SimpleHighlightQuery();
	//Set the highlighted field, and multiple fields can be added.
	HighlightOptions highlightOptions=new HighlightOptions().addField("item_title");
	highlightOptions.setSimplePrefix("<em style='color:red'>");//Highlight prefix 
	highlightOptions.setSimplePostfix("</em>");//Highlight suffix
	query.setHighlightOptions(highlightOptions);//Set highlight options
	//Query by keyword
	Criteria criteria=new Criteria("item_keywords").is(searchMap.get("keywords"));
	query.addCriteria(criteria);//Add query criteria
	HighlightPage<TbItem> page = solrTemplate.queryForHighlightPage(query, TbItem.class);//query
	for(HighlightEntry<TbItem> h: page.getHighlighted()){//Cycle highlight entry set
		TbItem item = h.getEntity();//Get the original entity class without highlighting
		if(h.getHighlights().size()>0 && h.getHighlights().get(0).getSnipplets().size()>0){
			item.setTitle(h.getHighlights().get(0).getSnipplets().get(0));//Set highlighted results
		}			
	}		
	map.put("rows",page.getContent());
	return map;
}

Note:
1.h.getHighlights() is the reason for the collection: there may be multiple domains

new HighlightOptions().addField("item_title").addField("item_price")...;

2. H. gethighlights(). Get (0). Getsniplets() is the reason for the collection: there may be multiple values, such as searching Samsung mobile phones, and Samsung and mobile phones represent two words to search from the title.
3. The back end passes the html tag to the front-end page, but the front-end page does not parse, but displays it as a string. Because the security mechanism of angularJS solves the following problems in order to avoid html injection attack:
Add filter and $sce service to base.js of front end

app.filter('trustHtml',['$sce',function($sce){//Write a filter named trustHtml to introduce services
    return function(data){
        return $sce.trustAsHtml(data);
    }
}]);

In the page: ng bind html is used to display the content of HTML

<div class="attr" ng-bind-html="item.title | trustHtml"></div>//item.title is the data in the filter

Group query

private  List searchCategoryList(Map searchMap){
	List<String> list=new ArrayList();	
	Query query=new SimpleQuery();		
	//Query by keyword
	Criteria criteria=new Criteria("item_keywords").is(searchMap.get("keywords"));
	query.addCriteria(criteria);
	//Set grouping options
	GroupOptions groupOptions=new GroupOptions().addGroupByField("item_category");
	query.setGroupOptions(groupOptions);
	//Get group page
	GroupPage<TbItem> page = solrTemplate.queryForGroupPage(query, TbItem.class);
	//Group result set by column
	GroupResult<TbItem> groupResult = page.getGroupResult("item_category");
	//Get group result entry page
	Page<GroupEntry<TbItem>> groupEntries = groupResult.getGroupEntries();
	//Get group entry set
	List<GroupEntry<TbItem>> content = groupEntries.getContent();
	for(GroupEntry<TbItem> entry:content){
		list.add(entry.getGroupValue());//Encapsulate the name of the grouping result into the return value	
	}
	return list;
}

Filtering queries

    ...
    Criteria filterCriteria=new Criteria("item_category").is(searchMap.get("category"));
	FilterQuery filterQuery=new SimpleFilterQuery(filterCriteria);
	query.addFilterQuery(filterQuery);
	...