《Elastic Stack 实战手册》——三、产品能力——3.5 进阶篇——3.5.19.Elasticsearch语言开发（Python/Nodejs/Java)——3.5.19.3.Elasticsearch语言开发（Java）(上) https://developer.aliyun.com/article/1226559
三、常见 API 使用
以下将围绕一个名为 posts 的索引进行常用 API 介绍。
1. Index API
向 posts 索引中写入一条数据。
public static void index() throws IOException { //构建 IndexRequest 并设置索引名称 IndexRequest request = new IndexRequest("posts"); //文档 id （可选，若不指定，ES 会主动生成） request.id("1"); //设置文档内容 此处选择以 JSON 字符串的形式构建文档内容， //其还支持 XContentBuilder、Map、Object key-pairs 的形式 String jsonString = "{" + "\"user\":\"kimchy\"," + "\"postDate\":\"2021-11-09\"," + "\"message\":\"trying out Elasticsearch\"" + "}"; request.source(jsonString, XContentType.JSON); IndexResponse indexResponse = client.index(request, RequestOptions.DEFAULT); System.out.println(indexResponse); }
结果输出：
IndexResponse[index=posts,type=_doc,id=1,version=1,result=updated ,seqNo=2,primaryTerm=1,shards={"total":2,"successful":1,"failed":0}]
2. Update API
将索引 posts 中 id 为1的文档 message 值更新为 "trying out update"。
public static void update() throws IOException { //构建 UpdateRequest 设置索引名称和文档 id UpdateRequest request = new UpdateRequest("posts", "1"); //设置更新内容 构建形式可类比 Index API String jsonString = "{" + "\"message\":\"trying out Update\"" + "}"; request.doc(jsonString, XContentType.JSON); //upsert 方法可以实现文档存在则更新，不存在则新增的效果。 //request.upsert(jsonString, XContentType.JSON); UpdateResponse updateResponse = client.update(request, RequestOptions.DEFAULT); System.out.println(updateResponse); }
结果输出：
UpdateResponse[index=posts,type=_doc,id=1,version=2,seqNo=3 ,primaryTerm=1,result=updated ,shards=ShardInfo{total=2, successful=1, failures=[]}]
3. Update By Query API
将索引 posts 中所有 user=kimchy 的文档 message 值更新为 "trying out UpdateByQuery"。此 API 需要用到 script 方式进行更新。
public static void updateByQuery() throws IOException { //构建 UpdateByQueryRequest 并设置索引名称 UpdateByQueryRequest request = new UpdateByQueryRequest("posts"); //版本冲突时继续执行 request.setConflicts("proceed"); //查询条件 request.setQuery(new TermQueryBuilder("user", "kimchy")); //设置更新脚本 Map<String, Object> params = new HashMap<>(); params.put("message", "trying out UpdateByQuery"); Script script = new Script(ScriptType.INLINE, "painless", "ctx._source.message = params.message", params); request.setScript(script); BulkByScrollResponse bulkResponse = client.updateByQuery(request, RequestOptions.DEFAULT); System.out.println(bulkResponse); }
结果输出：
BulkByScrollResponse[took=394ms,timed_out=false,sliceId=null,updated=1 ,created=0,deleted=0,batches=1,versionConflicts=0,noops=0,retries=0 ,throttledUntil=0s,bulk_failures=[],search_failures=[]]
4. Bulk API
对 posts 索引批量执行写入、更新、删除的操作。
public static void bulk() throws IOException { //构建 BulkRequest // 可添加多个DeleteRequest、UpdateRequest、IndexRequest BulkRequest request = new BulkRequest(); String jsonString = "{" + "\"user\":\"radish\"," + "\"postDate\":\"2021-11-09\"," + "\"message\":\"trying out bulk\"" + "}"; request.add(new IndexRequest("posts").id("2") .source(jsonString, XContentType.JSON)); // request.add(new DeleteRequest("posts", "1")); request.add(new UpdateRequest("posts", "1") .doc(XContentType.JSON, "message", "trying out bulk")); BulkResponse bulkResponse = client.bulk(request, RequestOptions.DEFAULT); System.out.println("bulk result:" + bulkResponse.hasFailures()); }
结果输出：
bulk hasFailures:false
5. Get API
获取 posts 索引中 id 为1的文档。
public static void get() throws IOException { //构建 GetRequest 并设置索引名称和文档 id GetRequest getRequest = new GetRequest("posts", "1"); GetResponse getResponse = client.get(getRequest, RequestOptions.DEFAULT); Map<String, Object> sourceAsMap = getResponse.getSourceAsMap(); System.out.println(sourceAsMap);
结果输出：
{postDate=2021-11-09, message=trying out Elasticsearch, user=kimchy}
6. Search API
对 posts 进行所有文档搜索。
public static void search() throws IOException { //构建 SearchRequest 并设置索引名称 SearchRequest searchRequest = new SearchRequest("posts"); //设置搜索条件 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //此处设置查询条件，应根据实际需求设置 searchSourceBuilder.query(QueryBuilders.matchAllQuery()); public static void search() throws IOException { //构建 SearchRequest 并设置索引名称 SearchRequest searchRequest = new SearchRequest("posts"); //设置搜索条件 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //此处设置查询条件，应根据实际需求设置 searchSourceBuilder.query(QueryBuilders.matchAllQuery());
结果输出：
{postDate=2021-11-09, message=trying out bulk, user=kimchy} {postDate=2021-11-09, message=trying out bulk, user=radish}
7. Delete API
删除 posts 索引 id 为1的文档。
public static void delete() throws IOException { //构建 DeleteRequest 并设置索引名称和文档 ID DeleteRequest request = new DeleteRequest("posts", "1"); DeleteResponse deleteResponse = client.delete(request, RequestOptions.DEFAULT); System.out.println(deleteResponse); }
结果输出：
DeleteResponse[index=posts,type=_doc,id=1,version=15,result=deleted, shards=ShardInfo{total=2, successful=1, failures=[]}]
8、DeleteByQuery API
删除索引 posts 中所有 user=radish 的文档。
public static void deleteByQuery() throws IOException { //构建 DeleteByQueryRequest 并指定索引名称 DeleteByQueryRequest request = new DeleteByQueryRequest("posts"); request.setQuery(new TermQueryBuilder("user", "radish")); BulkByScrollResponse bulkResponse = client.deleteByQuery(request, RequestOptions.DEFAULT); System.out.println(bulkResponse); }
结果输出：
BulkByScrollResponse[took=13ms,timed_out=false,sliceId=null,updated=0 ,created=0,deleted=0,batches=0,versionConflicts=0,noops=0,retries=0 ,throttledUntil=0s,bulk_failures=[],search_failures=[]]
四、完整示例
本节所涉及的代码示例均在此 github 仓库中：
https://github.com/lixueyu001/elasticsearch-java
参考
l https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.10/java-rest-high.html
