ES API

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1.maven引入ElasticSearch

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<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>7.8.0</version>
</dependency>
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-client</artifactId>
    <version>7.8.0</version>
</dependency>
<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>7.8.0</version>
</dependency>

2.设置ES config

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@Configuration
public class ElasticSearchConfig {
    @Bean
    public RestHighLevelClient restHighLevelClient() {
        HttpHost[] httpHosts = null;
        List<String> hostStrList = getHosts();// getHosts???????????
        if (hostStrList.size > 0) {
            httpHosts = new HttpHost[hostStrList.size()];
            for (int i = 0; i < hostStrList.size(); i++) {
                String[] s = hostStrList.get(i).split(":");
                String ip = s[0].trim();
                int port = Integer.valueOf(s[1].trim());
                httpHosts[i] = new HttpHost(ip, port, "http");								
            } 						
        }
        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(httpHosts));
        return client;				
    } 		
}

3.查询

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// 设置查询的索引库
SearchRequest searchRequest = new SearchRequest("search_index");

// 设置查询器
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
BoolQueryBuilder boolBuilder = QueryBuilders.boolQuery();

// 拼接查询条件, filter近似于must，但效率比must高，拼接条件=and
// should近似于or操作
// mustnot为!=
// termQuery为精确查找
boolBuilder.filter(QueryBuilders.termQuery("id",queryVo.getId()));
// matchQuery为模糊查询，会匹配带有相关的结果
boolBuilder.filter(QueryBuilders.matchQuery("name", queryVo.getName()));
// termsQuery近似于in，后面放数组即可
boolBuilder.filter(QueryBuilders.termsQuery("status",queryVo.getStatus().split(",") ));
// 分页，从第10笔资料开始，取20笔
searchSourceBuilder.from(10).size(20);
// 排序
searchSourceBuilder.sort("create_time", SortOrder.DESC);

searchRequest.source(searchSourceBuilder);
// 查询返回的结果集
SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);

SearchHits hits = searchResponse.getHits();
// 查询的具体结果
SearchHit[] searchHits = hits.getHits();
int total = searchHits.length;

4.滚动查询,统计总条数

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SearchRequest searchRequest = new SearchRequest("索引库");

SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
BoolQueryBuilder boolBuilder = QueryBuilders.boolQuery();

// 滚动查询
final Scroll scroll = new Scroll(TimeValue.timeValueMinutes(1L));
searchRequest.scroll(scroll);

// 条件查询
packageParamer(boolBuilder, queryVo);
searchSourceBuilder.query(boolBuilder);
// 设置每次最多查多少笔
searchSourceBuilder.size(5000);
// 排序
searchSourceBuilder.sort("ORDER_CREATE_TIME", SortOrder.DESC);
searchRequest.source(searchSourceBuilder);

SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
SearchHits hits = searchResponse.getHits();
SearchHit[] searchHits = hits.getHits();
int page = 1;
int total = searchHits.length;
// 若数据处于小于5000，则封装
int queryStart = (queryVo.getPage() -1 ) * queryVo.getSize();
if( queryStart <= 5000) {
    for(int i = 0; i < queryVo.getSize() && queryStart+i < searchHits.length; i++) {
        String json = JSON.toJSONString(searchHits[queryStart+i].getSourceAsMap(), SerializerFeature.WriteMapNullValue, SerializerFeature.WriteNullStringAsEmpty);
        ResultVo vo = JSON.parseObject(json, ResultVo.class);
        items.add(handleResultVo(vo));
    }
}

//遍历搜索命中的数据，直到没有数据
String scrollId = searchResponse.getScrollId();
while (searchHits != null && searchHits.length > 0) {
    SearchScrollRequest scrollRequest = new SearchScrollRequest(scrollId);
    scrollRequest.scroll(scroll);
    searchResponse = restHighLevelClient.scroll(scrollRequest, RequestOptions.DEFAULT);
    scrollId = searchResponse.getScrollId();
    searchHits = searchResponse.getHits().getHits();

    if (searchHits != null && searchHits.length > 0) {
        page++;
        total = (page-1) * 5000 + searchHits.length;
        boolean flag = queryStart >= (page-1)*5000 && queryStart < page * 5000;

        if (flag) {
            for(int i = 0; i < queryVo.getSize() && total - queryStart - i > 0; i++) {
                String json = JSON.toJSONString(searchHits[queryStart+i-(page-1)*5000].getSourceAsMap(), SerializerFeature.WriteMapNullValue, SerializerFeature.WriteNullStringAsEmpty);
                ResultVo vo = JSON.parseObject(json, ResultVo.class);
                items.add(handleResultVo(vo));
            }
        }
    }
}

// 清除滚屏
ClearScrollRequest clearScrollRequest = new ClearScrollRequest();
clearScrollRequest.addScrollId(scrollId);//也可以选择setScrollIds()将多个scrollId一起使用
ClearScrollResponse clearScrollResponse = restHighLevelClient.clearScroll(clearScrollRequest, RequestOptions.DEFAULT);
clearScrollResponse.isSucceeded();