牛客网项目——项目开发（八）：开发社区搜索功能

1. ElasticsearchService

1.1 注入bean

@Autowired
private DiscussPostRepository discussRepository;

@Autowired
private ElasticsearchTemplate elasticTemplate;

1.2 保存（修改）和删除

public void saveDiscussPost(DiscussPost post) {
   
    discussRepository.save(post);
}

public void deleteDiscussPost(int id) {
   
    discussRepository.deleteById(id);
}

1.3 搜索 searchDiscussPost

1. 返回参数：Page类型数据，封装多条数据
2. 传入参数：关键字keyword，当前页数current，每页显示数据limit
3. 搜索逻辑，参考前置技术（九）
   1. 查询关键字
   2. 排序
   3. 分页
   4. 高亮显示

public Page<DiscussPost> searchDiscussPost(String keyword, int current, int limit) {
   
    SearchQuery searchQuery = new NativeSearchQueryBuilder()
            .withQuery(QueryBuilders.multiMatchQuery(keyword, "title", "content"))
            .withSort(SortBuilders.fieldSort("type").order(SortOrder.DESC))
            .withSort(SortBuilders.fieldSort("score").order(SortOrder.DESC))
            .withSort(SortBuilders.fieldSort("createTime").order(SortOrder.DESC))
            .withPageable(PageRequest.of(current, limit))
            .withHighlightFields(
                    new HighlightBuilder.Field("title").preTags("<em>").postTags("</em>"),
                    new HighlightBuilder.Field("content").preTags("<em>").postTags("</em>")
            ).build();

    return elasticTemplate.queryForPage(searchQuery, DiscussPost.class, new SearchResultMapper() {
   
        @Override
        public <T> AggregatedPage<T> mapResults(SearchResponse response, Class<T> aClass, Pageable pageable) {
   
            SearchHits hits = response.getHits();
            if (hits.getTotalHits() <= 0) {
   
                return null;
            }

            List<DiscussPost> list = new ArrayList<>();
            for (SearchHit hit : hits) {
   
                DiscussPost post = new DiscussPost();

                String id = hit.getSourceAsMap().get("id").toString();
                post.setId(Integer.valueOf(id));

                String userId = hit.getSourceAsMap().get("userId").toString();<