26-RestHighLevelClient----高亮&分頁&排序&指定返回字段

高亮查詢和query同時使用時，高亮查詢的字段和query字段需要一致。若query查詢全部，而高亮查詢是查詢某一個特定字段，則高亮查詢不會生效

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@SpringBootTest
public class RestHighLevelClientOpsTest {

    private RestHighLevelClient restHighLevelClient;

    @Autowired
    public RestHighLevelClientOpsTest(RestHighLevelClient restHighLevelClient) {
        this.restHighLevelClient = restHighLevelClient;
    }

    /**
     * 查詢所有 分頁查詢 form 起始位置  size 每頁展示記錄的條數
     */
    @Test
    public void testSearch() throws IOException {
        SearchRequest searchRequest = new SearchRequest("products");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.query(QueryBuilders.matchAllQuery())
                .from(0)    //起始位置：start=（page-1）*size
                .size(1);   //每頁顯示條數

        searchRequest.source(sourceBuilder);

        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

        System.out.println("總條數：" + search.getHits().getTotalHits().value);
        System.out.println("獲取文檔最大得分：" + search.getHits().getMaxScore());

        SearchHit[] hits = search.getHits().getHits();
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }
    }

    /**
     * 查詢結果默認是按分數排序，我們可以手動指定排序規則
     * 排序：按價格排序
     */
    @Test
    public void testSort() throws IOException {
        SearchRequest searchRequest = new SearchRequest("products");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.query(QueryBuilders.matchAllQuery()).sort("price", SortOrder.ASC);
        searchRequest.source(sourceBuilder);

        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

        System.out.println("總條數：" + searchResponse.getHits().getTotalHits().value);
        System.out.println("最大得分：" + searchResponse.getHits().getMaxScore());

        SearchHit[] hits = searchResponse.getHits().getHits();
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }
    }

    /**
     * 指定返回的字段
     */
    @Test
    public void testReturn() throws IOException {
        SearchRequest searchRequest = new SearchRequest("products");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

        //之所以設置兩個數組，是因為如果我們字段很多的時候，我們業務需求只希望查詢/排除很少一部分的字段，則只需要在查詢/排除數組里面寫那僅有的幾個字段即可，省時省力
        sourceBuilder.query(QueryBuilders.matchAllQuery()).fetchSource(new String[]{"title"}, new String[]{});//參數1：包含的字段數組   參數2：排除的字段數組

        searchRequest.source(sourceBuilder);

        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

        System.out.println("總條數：" + searchResponse.getHits().getTotalHits().value);
        System.out.println("最大得分：" + searchResponse.getHits().getMaxScore());

        SearchHit[] hits = searchResponse.getHits().getHits();
        for (SearchHit hit : hits) {
            System.out.println(hit.getSourceAsString());
        }
    }

    /**
     * 高亮查詢
     */
    @Test
    public void testHighlight() throws IOException {
        SearchRequest searchRequest = new SearchRequest("products");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

        //高亮器
        HighlightBuilder highlightBuilder = new HighlightBuilder();
        highlightBuilder.requireFieldMatch(false)//因為高亮查詢默認是對查詢字段即description就行高亮，可以關閉字段匹配，這樣就可以對查詢到的多個字段（前提是有關鍵詞並且改字段可以分詞）進行高亮顯示
                        .field("description")//若有關鍵字切可以分詞，則可以高亮，寫*可以匹配所有字段
                        .field("title")//若有關鍵字切可以分詞，則可以高亮，寫*可以匹配所有字段
                        .preTags("<span style='color:red;'>")//手動前綴標簽
                        .postTags("</span>");

        sourceBuilder.query(QueryBuilders.termQuery("description", "好吃")).highlighter(highlightBuilder);///高亮搜索
        searchRequest.source(sourceBuilder);

        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHit[] hits = searchResponse.getHits().getHits();
        for (SearchHit hit : hits) {
            //獲取高亮字段
            Map<String, HighlightField> highlightFields = hit.getHighlightFields();

            //如果高亮字段包含在description中
            if (highlightFields.containsKey("description")){
                System.out.println("description中有這個字段");
                Text[] fragments = highlightFields.get("description").getFragments();
                for (Text fragment : fragments) {
                    System.out.println(fragment);
                }
            }

            //如果高亮字段包含在title中
            if (highlightFields.containsKey("title")){
                System.out.println("title中有這個字段");
                Text[] fragments = highlightFields.get("title").getFragments();
                for (Text fragment : fragments) {
                    System.out.println(fragment);
                }
            }
        }
    }
}