本文转自SDK社区:sdk.cn
一、创建连接
!ps:RestHighLevelClient是官方指定的连接API。另外一个是TransportClient，但是TransportClient这个是已经废弃不用的，所以会在ES8.0之后完全移除，也就是说8.0之后就无法使用了
RestHighLevelClient的maven依赖为（使用前必须添加相应依赖）
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>7.9.2</version>
</dependency>
<dependency>
<groupId>org.elasticsearch</groupId>
<artifactId>elasticsearch</artifactId>
<version>7.9.2</version>
</dependency>
注意：以上的依赖版本可以根据你使用的ES的版本来定，向下兼容，但是无法向上兼容
创建连接
static String ip = "localhost";
static int port = 9200;
static RestHighLevelClient restHighLevelClient = null;
static TransportClient client = null;
static RestHighLevelClient initClient(){
//这里的RestClient.builder(new HttpHost(ip,port),.........)支持多个httphost连接，也就是支持连接多个elasticsearch
restHighLevelClient = new RestHighLevelClient(RestClient.builder(new HttpHost(ip,port)));
}
static Connection getInstance(){
synchronized (ElasticSearchFactory.class){
if (restHighLevelClient == null){
restHighLevelClient = initClient();
}
}
return connection;
}
RestHighLevelClient 支持对ES的增删改查、批量操作
新增：
public static void creatIndex(String json){
IndexRequest indexRequest = new IndexRequest("test_index","String");
indexRequest.source(json, XContentType.JSON);//这里的json为存入ES的文档内容
try {
restHighLevelClient.index(indexRequest, RequestOptions.DEFAULT);//RequestOptions在新方法中必须选择
} catch (IOException e) {
e.printStackTrace();
}
}
查询：
查询支持直接查询和条件查询，由于ES是根据索引、文档类型和文档ID确定一个唯一的文档的，所以直接查询必须要有索引和类型还有ID
public static Map<String, Object> getIndex(String indexName,String type,String id){
GetRequest request = new GetRequest(indexName);
//SearchRequest searchRequest = new SearchRequest(indexName);
try {
GetResponse search = restHighLevelClient.get(request, RequestOptions.DEFAULT);
Map<String, Object> source = search.getSource();
return source;
} catch (IOException e) {
e.printStackTrace();
}
return new HashMap<>();
}
条件查询：
条件查询支持所有的ES的查询规则
public static Map<String, Object> searchIndex(String indexName){
//GetRequest request = new GetRequest(indexName);
//SearchRequest searchRequest = new SearchRequest(indexName);
QueryBuilder queryBuilders = QueryBuilders.boolQuery().filter(
QueryBuilders.termQuery("queryKey","吱吱吱ZZZ")
);
SearchRequest searchRequest = new SearchRequest();
//searchRequest.indices("posts");这里可以设计GEET或者POST
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
// searchSourceBuilder.sort(new ScoreSortBuilder().order(SortOrder.DESC));支持按评分排序，评分是指分词之后取得的文档相似度评分
searchSourceBuilder.query(QueryBuilders.boolQuery().filter(QueryBuilders.termQuery("queryKey.keyword","吱吱吱ZZZ")));
searchRequest.source(searchSourceBuilder);
try {
SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
SearchHit[] hits = search.getHits().getHits();
for (SearchHit searchHit : hits){
Map<String, Object> sourceAsMap = searchHit.getSourceAsMap();
System.out.println("source : {}" + sourceAsMap.toString());
}
} catch (IOException e) {
e.printStackTrace();
}
return new HashMap<>();
}
修改：
ps:ES中其实并不存在真正意义上的修改，其实是进行的文档覆盖，先将原文档查出来标记删除，然后在原文档的基础上添加上修改形成一份新文档，存入ES中，之后再将打上删除标记的文档删除。
public static void updateIndex(String indexName, String type, String id, String json){
UpdateRequest request = new UpdateRequest(indexName, type, id);
request.doc(json, XContentType.JSON);
try {
UpdateResponse updateResponse = restHighLevelClient.update(request,RequestOptions.DEFAULT);
} catch (IOException e) {
e.printStackTrace();
}
}
删除:
public static void deleteIndex(String indexName, String type, String id){
DeleteRequest request = new DeleteRequest(indexName,type,id);
try {
restHighLevelClient.delete(request,RequestOptions.DEFAULT);
} catch (IOException e) {
e.printStackTrace();
}
}
bulk操作，bulk操作相当于批处理，能够在一次操作中处理一批数据，同时能够同时处理，增删改操作
public static void bulkIndex(){
BulkRequest request = new BulkRequest();
String jsonString="{\n" +
"\t\"databaseId\": \"謝謝謝謝謝謝\",\n" +
"\t\"databaseType\": \"嘻嘻嘻\",\n" +
"\t\"queryKey\":\"吱吱吱ZZZ\"\n" +
"}\n";
UUID uuid = UUID.randomUUID();
request.add(new IndexRequest("test_index", "String", uuid.toString())
.source(jsonString,XContentType.JSON));
String updateJson="{\n" +
" \"queryKey\":\"吱吱吱ZZZ\"\n" +
"}";
request.add(new UpdateRequest("test_index", "String", uuid.toString())
.doc(updateJson,XContentType.JSON));
request.add(new DeleteRequest("test_index", "String", uuid.toString()));
try {
restHighLevelClient.bulk(request, RequestOptions.DEFAULT);
} catch (IOException e) {
e.printStackTrace();
}
}
执行ES-DSL
String json = "{\"bool\":{\"filter\":[{\"term\":{\"queryKey.keyword\":\"吱吱吱ZZZ\"}}]}}";
String index= "test_index";
public static void wapQuerty(String json,String index){
WrapperQueryBuilder queryBuilder = new WrapperQueryBuilder(json);
SearchRequest searchRequest = new SearchRequest();
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(queryBuilder);
searchRequest.source(searchSourceBuilder).indices(index);
try {
SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
SearchHit[] hits = search.getHits().getHits();
for (SearchHit searchHit : hits){
Map<String, Object> sourceAsMap = searchHit.getSourceAsMap();
String id = searchHit.getId();
System.out.println("id:"+id);
}
} catch (IOException e) {
e.printStackTrace();
}
}
