Java 代码 查询elasticsearch 索引内容

你可以使用 Java High Level REST Client 来查询 Elasticsearch 索引内容。以下是一个简单的示例代码：

RestHighLevelClient client = new RestHighLevelClient(
        RestClient.builder(new HttpHost("localhost", 9200, "http")));

SearchRequest searchRequest = new SearchRequest("your_index_name");
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.matchQuery("your_field_name", "your_keyword"));
searchRequest.source(searchSourceBuilder);

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

SearchHits hits = searchResponse.getHits();

for (SearchHit hit : hits) {
    Map<String, Object> sourceAsMap = hit.getSourceAsMap();
    System.out.println(sourceAsMap);
}

client.close();

这个代码将会查询名为 `your_index_name` 的索引中，包含关键字 `your_keyword` 的文档，并将查询结果输出到控制台。你需要将 `your_field_name` 替换为你想要匹配的字段名。