ElasticSearch集群及部分基础应用总结

首先这里用的有关ElasticSearch依赖有：

            org.elasticsearch.client
            elasticsearch-rest-high-level-client
            7.5.1
        
        
            org.elasticsearch
            elasticsearch
            7.5.1
            compile
        
        
            org.elasticsearch.client
            elasticsearch-rest-client
            7.5.1
            compile

编写一个util

public  class ElasticSearchUtil {

    public static RestHighLevelClient restHighLevelClient() {

        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                //127.0.0.1与9200是本地，若在本地中正常调用一个即可，若调用集群则new 多个HttpHost 如下所示：
                         new HttpHost("127.0.0.1", 9200, "http")，
                         new HttpHost("127.0.0.1", 9200, "http"),
                         new HttpHost("127.0.0.1", 9200, "http"))
        );
        //返回
        return client;
    }
}

 //调用client连接
            RestHighLevelClient client = ElasticSearchUtil.restHighLevelClient();
            SearchRequest searchRequest = new SearchRequest("索引");
            //构建索引条件
            SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

//sourceBuilder中有sort、size、searchAfter，可进行排序分页

超时时间30s

            sourceBuilder.timeout(new Timevalue(30, TimeUnit.SECONDS));

查找或排序后的封装到searchRequest

searchRequest.source(sourceBuilder);
            SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);
            for (SearchHit hit : response.getHits().getHits()) {
                //将获取的值转换成map的形式
                Map map = hit.getSourceAsMap();
                XXX xx = JSON.parseObject(JSON.toJSonString(map), XXX.class);
                list.add(xx);
            }