本文轉自:https://www.cnblogs.com/swordfall/p/9981883.html
1. Elasticsearch Java API有四類client連接方式
- TransportClient
- RestClient
- Jest
- Spring Data Elasticsearch
其中TransportClient和RestClient是Elasticsearch原生的api。TransportClient可以支持2.x,5.x版本,TransportClient將會在Elasticsearch 7.0棄用並在8.0中完成刪除,替而代之,我們使用Java High Level REST Client,它使用HTTP請求而不是Java序列化請求。
Jest是Java社區開發的,是Elasticsearch的Java Http Rest客戶端;Spring Data Elasticsearch是spring集成的Elasticsearch開發包。
建議:TransportClient將會在後面的版本中棄用,因此不推薦後續使用;而Jest由於是社區維護,所以更新有一定延遲,目前最新版對接ES6.3.1,近一個月只有四個issue,說明整體活躍度較低,因此也不推薦使用;Spring Data Elasticsearch主要是與Spring生態對接,可以在web系統中整合到Spring中使用。目前比較推薦使用官方的高階、低階Rest Client,官方維護,比較值得信賴。本文主要介紹RestClient,其他的只做簡單概述。
2. TransportClient
這裏考慮到後面版本將棄用TransportClinet,主要簡單介紹TransportClient的創建、以及一些基本增刪改查操作。
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>transport</artifactId>
<version>6.4.3</version>
</dependency>
<dependency>
<groupId>org.elasticsearch</groupId>
<artifactId>elasticsearch</artifactId>
<version>6.4.3</version>
</dependency>
/**
* @Author: Yang JianQiu
* @Date: 2018/11/12 16:40
*
* transportClient將會在7.0版本上過時,並在8.0版本上移除掉,建議使用Java High Level REST Client
*/
public class TransportClientUtils {
private TransportClient client = null;
/**
* 這裏使用餓漢單例模式創建TransportClient
*/
public TransportClientUtils() {
if (client == null){
synchronized (TransportClientUtils.class){
if (client == null){
client = getClient();
}
}
}
}
public TransportClient getClient(){
TransportClient client = null;
try {
Settings settings = Settings.builder()
.put("client.transport.sniff", true)
.put("cluster.name", "bigdata").build();
client = new PreBuiltTransportClient(settings)
.addTransportAddress(new TransportAddress(new InetSocketAddress("192.168.187.201", 9300)));
} catch (Exception e) {
e.printStackTrace();
}
return client;
}
public viod test(){
//增,插入記錄
IndexResponse response = client.prepareIndex("twitter", "_doc")
.setSource(json, XContentType.JSON)
.get();
//根據Id查詢
GetResponse response = client.prepareGet("twitter", "_doc", 1).get();
//根據Id刪除
DeleteResponse response = client.prepareDelete("twitter", "_doc", 1).get();
//根據Id更新對應的字段
UpdateRequest updateRequest1 = new UpdateRequest("twitter", "_doc", "NpEWCGcBi36MQkKOSdf3")
.doc(jsonBuilder()
.startObject()
.field("user", "tom")
.endObject()
);
client.update(updateRequest1).get();
//另外還有批處理API、search負責查詢API、Aggregate聚合API...
}
}
具體的TransportClient的其他API應用可以參考Elasticsearch的TransportClient API doc:https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/index.html
3. Rest Client
後面的elasticSearch版本將主要使用Rest Client操作數據。
Rest Client分爲Java Low REST Client和Java High Level REST Client。
maven的依賴包:
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>6.4.3</version>
</dependency>
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-client</artifactId>
<version>6.4.3</version>
</dependency>
<dependency>
<groupId>org.elasticsearch</groupId>
<artifactId>elasticsearch</artifactId>
<version>6.4.3</version>
</dependency>
RestHighLevelClient與RestClient的創建:
/**
* @author: Swordfall Yeung
* @date:
* @desc:
*/
public class RestClientUtils {
/**
* 高階Rest Client
*/
private RestHighLevelClient client = null;
/**
* 低階Rest Client
*/
private RestClient restClient = null;
/**
* 這裏使用餓漢單例模式創建RestHighLevelClient
*/
public RestClientUtils() {
if (client == null) {
synchronized (RestHighLevelClient.class) {
if (client == null) {
client = getClient();
}
}
}
}
private RestHighLevelClient getClient() {
RestHighLevelClient client = null;
try {
client = new RestHighLevelClient(
RestClient.builder(
new HttpHost("192.168.187.201", 9300, "http")
)
);
} catch (Exception e) {
e.printStackTrace();
}
return client;
}
private RestClient getRestClient() {
RestClient client = null;
try {
client = RestClient.builder(
new HttpHost("192.168.187.201", 9300, "http")
).build();
} catch (Exception e) {
e.printStackTrace();
}
return client;
}
public void closeClient() {
try {
if (client != null) {
client.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* document API 主要是些簡單的增刪改查操作
*/
public void documentAPI() {
//...
}
/**
* Search API 主要是些複雜查詢操作
*/
public void searchAPI() {
//...
}
}
RestHighLevelAPI分爲Document APIs、Search APIs、Miscellaneous APIs、Indices APIs、Cluster APIs...等等,這裏主要介紹常用的Document APIs和Search APIs,其餘的APIs可以參考:https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high.html
3.1 Document APIs
Document APIs主要涉及些增刪改查等操作,包括Single document APIs單條操作和Multi-document APIs批量操作。Document APIs均可以設置可選參數,實現同步、異步,也均可拋出異常,這裏以Index API爲例,後面的不再簡述。
Index API介紹:
/**
* 增,插入記錄
* 插入操作有四種方式,分同步異步操作,可選參數設置,結果返回IndexResponse,拋出異常
* @throws Exception
*/
public void index() throws Exception{
//第一種方式: String
IndexRequest request = new IndexRequest("posts", "doc", "1");
String jsonString = "{" +
"\"user\":\"kimchy\"," +
"\"postDate\":\"2013-01-30\"," +
"\"message\":\"trying out Elasticsearch\"" +
"}";
request.source(jsonString, XContentType.JSON);
//第二種方式: Map
Map<String, Object> jsonMap = new HashMap<>();
jsonMap.put("user", "kimchy");
jsonMap.put("postDate", new Date());
jsonMap.put("message", "trying out Elasticsearch");
IndexRequest indexRequest = new IndexRequest("posts", "doc", "1").source(jsonMap);
//第三種方式: XContentBuilder automatically converted to JSON
XContentBuilder builder = XContentFactory.jsonBuilder();
builder.startObject();
{
builder.field("user", "kimchy");
builder.timeField("postDate" , new Date());
builder.field("message", "trying out Elasticsearch");
}
builder.endObject();
IndexRequest indexRequest1 = new IndexRequest("posts", "doc", "1")
.source(builder);
//第四種方式: source -> key-pairs
IndexRequest indexRequest2 = new IndexRequest("posts", "doc", "1")
.source("user", "kimchy",
"postDate", new Date(),
"message", "trying out Elasticsearch"
);
//可選的參數設置
request.routing("routing");
request.parent("parent");
request.timeout(TimeValue.timeValueSeconds(1));
request.timeout("1s");
request.setRefreshPolicy(WriteRequest.RefreshPolicy.WAIT_UNTIL);
request.setRefreshPolicy("wait_for");
request.version(2);
request.versionType(VersionType.EXTERNAL);
request.opType(DocWriteRequest.OpType.CREATE);
request.opType("create");
request.setPipeline("pipeline");
//同步執行
IndexResponse indexResponse = client.index(request, RequestOptions.DEFAULT);
//異步執行
ActionListener<IndexResponse> listener = new ActionListener<IndexResponse>() {
@Override
public void onResponse(IndexResponse indexResponse) {
}
@Override
public void onFailure(Exception e) {
}
};
client.indexAsync(request, RequestOptions.DEFAULT, listener);
//Index Response
String index = indexResponse.getIndex();
String type = indexResponse.getType();
String id = indexResponse.getId();
long version = indexResponse.getVersion();
//拋出異常
IndexRequest request1 = new IndexRequest("posts", "doc", "1")
.source("field", "value")
.version(1);
try {
IndexResponse response = client.index(request, RequestOptions.DEFAULT);
} catch (ElasticsearchException e) {
if (e.status() == RestStatus.CONFLICT){
}
}
}
Get API介紹
/**
* 根據 id 獲取數據
* @throws Exception
*/
public void get() throws Exception{
GetRequest request = new GetRequest("posts", "doc", "1");
//可選參數設置
request.fetchSourceContext(FetchSourceContext.DO_NOT_FETCH_SOURCE);
String[] includes = new String[]{"message", "*Date"};
String[] excludes = Strings.EMPTY_ARRAY;
FetchSourceContext fetchSourceContext = new FetchSourceContext(true, includes, excludes);
request.fetchSourceContext(fetchSourceContext);
//同步執行
GetResponse getResponse = client.get(request, RequestOptions.DEFAULT);
//異步執行 listener的寫法參照Index的異步執行的listener
client.getAsync(request, RequestOptions.DEFAULT, listener);
//Get Response 獲取信息
//拋出異常
}
Exists API介紹
/**
* 是否存在
* @throws Exception
*/
public void exists() throws Exception{
GetRequest getRequest = new GetRequest("posts", "doc", "1");
getRequest.fetchSourceContext(new FetchSourceContext(false));
getRequest.storedFields("_none_");
//同步執行
boolean exists = client.exists(getRequest, RequestOptions.DEFAULT);
//異步執行 listener的寫法參照Index的
client.existsAsync(getRequest, RequestOptions.DEFAULT, listener);
if (exists){
System.out.println("存在");
}else {
System.out.println("不存在");
}
}
Delete API介紹
/**
* 根據id刪除
* @throws Exception
*/
public void delete() throws Exception{
DeleteRequest request = new DeleteRequest("posts", "doc", "1");
//同步執行
DeleteResponse deleteResponse = client.delete(request, RequestOptions.DEFAULT);
//異步執行 listener參照index的
client.deleteAsync(request, RequestOptions.DEFAULT, listener);
//Delete Response
String index = deleteResponse.getIndex();
// document was not found
if (deleteResponse.getResult() == DocWriteResponse.Result.NOT_FOUND) {
}
//拋出異常
}
Update API介紹
/**
* 根據id更新
* @throws Exception
*/
public void update() throws Exception{
UpdateRequest request = new UpdateRequest("posts", "doc", "1");
Map<String, Object> parameters = Collections.singletonMap("count", 4);
//第一種方式:inline script
Script inline = new Script(ScriptType.INLINE, "painless", "ctx._source.field += params.count", parameters);
request.script(inline);
//第二種方式:stored script
Script stored = new Script(ScriptType.STORED, null, "increment-field", parameters);
request.script(stored);
//第三種方式:partial document String
String jsonString = "{" +
"\"updated\":\"2017-01-01\"," +
"\"reason\":\"daily update\"" +
"}";
request.doc(jsonString, XContentType.JSON);
//第四種方式:partial document Map
Map<String, Object> jsonMap = new HashMap<>();
jsonMap.put("updated", new Date());
jsonMap.put("reason", "daily update");
request.doc(jsonMap);
//第五種方式:partial document XContentBuilder
XContentBuilder builder = XContentFactory.jsonBuilder();
builder.startObject();
{
builder.timeField("updated", new Date());
builder.field("reason", "daily update");
}
builder.endObject();
request.doc(builder);
//第六種方式:partial document Object key-pairs
request.doc("updated", new Date(),
"reason", "daily update");
//upserts
String jsonString1 = "{\"created\":\"2017-01-01\"}";
request.upsert(jsonString1, XContentType.JSON);
//同步執行
UpdateResponse updateResponse = client.update(request, RequestOptions.DEFAULT);
//異步執行, listener創建參考index的
client.updateAsync(request, RequestOptions.DEFAULT, listener);
//update Response
GetResult result = updateResponse.getGetResult();
if (result.isExists()) {
String sourceAsString = result.sourceAsString();
Map<String, Object> sourceAsMap = result.sourceAsMap();
byte[] sourceAsBytes = result.source();
} else {
}
//拋出異常
}
Bulk API介紹
/**
* 批量處理
* @throws Exception
*/
public void bulk() throws Exception{
BulkRequest request = new BulkRequest();
//Other
request.add(new DeleteRequest("posts", "doc", "3"));
request.add(new UpdateRequest("posts", "doc", "2")
.doc(XContentType.JSON, "other", "test"));
request.add(new IndexRequest("posts", "doc", "4")
.source(XContentType.JSON, "field", "baz"));
//同步執行
BulkResponse bulkResponses = client.bulk(request, RequestOptions.DEFAULT);
//異步執行
ActionListener<BulkResponse> listener = new ActionListener<BulkResponse>() {
@Override
public void onResponse(BulkResponse bulkResponse) {
}
@Override
public void onFailure(Exception e) {
}
};
client.bulkAsync(request, RequestOptions.DEFAULT, listener);
//Bulk Response 批處理結果
for (BulkItemResponse bulkItemResponse: bulkResponses){
DocWriteResponse itemResponse = bulkItemResponse.getResponse();
if (bulkItemResponse.getOpType() == DocWriteRequest.OpType.INDEX
|| bulkItemResponse.getOpType() == DocWriteRequest.OpType.CREATE) {
IndexResponse indexResponse = (IndexResponse) itemResponse;
} else if (bulkItemResponse.getOpType() == DocWriteRequest.OpType.UPDATE) {
UpdateResponse updateResponse = (UpdateResponse) itemResponse;
} else if (bulkItemResponse.getOpType() == DocWriteRequest.OpType.DELETE) {
DeleteResponse deleteResponse = (DeleteResponse) itemResponse;
}
}
for (BulkItemResponse bulkItemResponse : bulkResponses) {
if (bulkItemResponse.isFailed()) {
BulkItemResponse.Failure failure = bulkItemResponse.getFailure();
}
}
//Bulk Processor 自定義批處理器
BulkProcessor.Listener listener1 = new BulkProcessor.Listener() {
@Override
public void beforeBulk(long l, BulkRequest bulkRequest) {
}
@Override
public void afterBulk(long l, BulkRequest bulkRequest, BulkResponse bulkResponse) {
}
@Override
public void afterBulk(long l, BulkRequest bulkRequest, Throwable throwable) {
}
};
BiConsumer<BulkRequest, ActionListener<BulkResponse>> bulkConsumer =
(request1, bulkListener) -> client.bulkAsync(request1, RequestOptions.DEFAULT, bulkListener);
BulkProcessor bulkProcessor = BulkProcessor.builder(bulkConsumer, listener1).build();
BiConsumer<BulkRequest, ActionListener<BulkResponse>> bulkConsumer1 =
(request2, bulkListener) -> client.bulkAsync(request2, RequestOptions.DEFAULT, bulkListener);
BulkProcessor.Builder builder = BulkProcessor.builder(bulkConsumer1, listener1);
builder.setBulkActions(500);
builder.setBulkSize(new ByteSizeValue(1L, ByteSizeUnit.MB));
builder.setConcurrentRequests(0);
builder.setFlushInterval(TimeValue.timeValueSeconds(10L));
builder.setBackoffPolicy(BackoffPolicy
.constantBackoff(TimeValue.timeValueSeconds(1L), 3));
//Once the BulkProcessor is created requests can be added to it:
IndexRequest one = new IndexRequest("posts", "doc", "1").
source(XContentType.JSON, "title",
"In which order are my Elasticsearch queries executed?");
IndexRequest two = new IndexRequest("posts", "doc", "2")
.source(XContentType.JSON, "title",
"Current status and upcoming changes in Elasticsearch");
IndexRequest three = new IndexRequest("posts", "doc", "3")
.source(XContentType.JSON, "title",
"The Future of Federated Search in Elasticsearch");
bulkProcessor.add(one);
bulkProcessor.add(two);
bulkProcessor.add(three);
boolean terminated = bulkProcessor.awaitClose(30L, TimeUnit.SECONDS);
}
Multi-Get API介紹
/**
* 根據id批量獲取數據
* @throws Exception
*/
public void multiGet() throws Exception{
MultiGetRequest request = new MultiGetRequest();
request.add(new MultiGetRequest.Item("index","type","example_id"));
request.add(new MultiGetRequest.Item("index", "type", "another_id"));
//optional arguments
request.add(new MultiGetRequest.Item("index", "type", "example_id") .fetchSourceContext(FetchSourceContext.DO_NOT_FETCH_SOURCE));
//同步執行
MultiGetResponse responses = client.mget(request, RequestOptions.DEFAULT);
//異步執行 listener參考Index的
client.mgetAsync(request, RequestOptions.DEFAULT, listener);
//Multi Get Response
MultiGetItemResponse firstItem = response.getResponses()[0];
GetResponse firstGet = firstItem.getResponse();
if (firstGet.isExists()) {
}
}
3.2 Search APIs
public void search() throws Exception{
//match all query 查詢所有數據
SearchRequest searchRequest = new SearchRequest();
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.matchAllQuery());
searchRequest.source(searchSourceBuilder);
//使用SearchSourceBuilder查詢指定字段
SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder.query(QueryBuilders.termQuery("user", "kimchy"));
sourceBuilder.from(0);
sourceBuilder.size(5);
sourceBuilder.timeout(new TimeValue(60, TimeUnit.SECONDS));
SearchRequest searchRequest2 = new SearchRequest();
//index 數據庫
searchRequest2.indices("posts");
searchRequest2.source(sourceBuilder);
//Building queries
//One way, QueryBuilder can be created using its constructor 使用QueryBuilder的構造函數
MatchQueryBuilder matchQueryBuilder = new MatchQueryBuilder("user", "kimchy");
matchQueryBuilder.fuzziness(Fuzziness.AUTO);
matchQueryBuilder.prefixLength(3);
matchQueryBuilder.maxExpansions(10);
//Two way, QueryBuilder objects can also be created using the QueryBuilders utility class. 直接使用matchQuery
QueryBuilder matchQueryBuilder1 = matchQuery("user", "kimchy")
.fuzziness(Fuzziness.AUTO)
.prefixLength(3)
.maxExpansions(10);
searchSourceBuilder.query(matchQueryBuilder1);
//Specifying Sorting 指定排序
sourceBuilder.sort(new ScoreSortBuilder().order(SortOrder.DESC));
sourceBuilder.sort(new FieldSortBuilder("_uid").order(SortOrder.ASC));
//Source filtering, turn off _source retrieval completely
sourceBuilder.fetchSource(false);
//an array of one or more wildcard patterns to control which fields get included or excluded in a more fine grained way
String[] includeFields = new String[] {"title", "user", "innerObject.*"};
String[] excludeFields = new String[] {"_type"};
sourceBuilder.fetchSource(includeFields, excludeFields);
//Requesting Aggregations
SearchSourceBuilder searchSourceBuilder2 = new SearchSourceBuilder();
TermsAggregationBuilder aggregation = AggregationBuilders.terms("by_company")
.field("company.keyword");
aggregation.subAggregation(AggregationBuilders.avg("average_age")
.field("age"));
searchSourceBuilder2.aggregation(aggregation);
//Requesting Suggestions
SearchSourceBuilder searchSourceBuilder3 = new SearchSourceBuilder();
SuggestionBuilder termSuggestionBuilder = SuggestBuilders.termSuggestion("user").text("kmichy");
SuggestBuilder suggestBuilder = new SuggestBuilder();
suggestBuilder.addSuggestion("suggest_user", termSuggestionBuilder);
searchSourceBuilder3.suggest(suggestBuilder);
//同步執行
SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
//異步執行 listener參考index的
client.searchAsync(searchRequest, RequestOptions.DEFAULT, listener);
//SearchResponse
RestStatus status = searchResponse.status();
for (ShardSearchFailure failure : searchResponse.getShardFailures()) {
// failures should be handled here
}
//Retrieving SearchHits 獲取結果數據
SearchHits hits = searchResponse.getHits();
long totalHits = hits.getTotalHits();
float maxScore = hits.getMaxScore();
SearchHit[] searchHits = hits.getHits();
for (SearchHit hit : searchHits) {
// do something with the SearchHit
String index = hit.getIndex();
String type = hit.getType();
String id = hit.getId();
float score = hit.getScore();
String sourceAsString = hit.getSourceAsString();
Map<String, Object> sourceAsMap = hit.getSourceAsMap();
String documentTitle = (String) sourceAsMap.get("title");
List<Object> users = (List<Object>) sourceAsMap.get("user");
Map<String, Object> innerObject =
(Map<String, Object>) sourceAsMap.get("innerObject");
}
//Retrieving Aggregations
Aggregations aggregations = searchResponse.getAggregations();
Terms byCompanyAggregation = aggregations.get("by_company");
Terms.Bucket elasticBucket = byCompanyAggregation.getBucketByKey("Elastic");
Avg averageAge = elasticBucket.getAggregations().get("average_age");
double avg = averageAge.getValue();
Range range = aggregations.get("by_company");
Map<String, Aggregation> aggregationMap = aggregations.getAsMap();
Terms companyAggregation = (Terms) aggregationMap.get("by_company");
List<Aggregation> aggregationList = aggregations.asList();
for (Aggregation agg : aggregations) {
String type = agg.getType();
if (type.equals(TermsAggregationBuilder.NAME)) {
Terms.Bucket elasticBucket1 = ((Terms) agg).getBucketByKey("Elastic");
long numberOfDocs = elasticBucket1.getDocCount();
}
}
//Retrieving Suggestions
Suggest suggest = searchResponse.getSuggest();
TermSuggestion termSuggestion = suggest.getSuggestion("suggest_user");
for (TermSuggestion.Entry entry : termSuggestion.getEntries()) {
for (TermSuggestion.Entry.Option option : entry) {
String suggestText = option.getText().string();
}
}
}
Multi-search APIs介紹:
public void multiSearch() throws Exception{
MultiSearchRequest request = new MultiSearchRequest();
SearchRequest firstSearchRequest = new SearchRequest();
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.matchQuery("user", "kimchy"));
firstSearchRequest.source(searchSourceBuilder);
request.add(firstSearchRequest);
SearchRequest secondSearchRequest = new SearchRequest();
searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.matchQuery("user", "luca"));
secondSearchRequest.source(searchSourceBuilder);
request.add(secondSearchRequest);
//同步執行
MultiSearchResponse response = client.msearch(request, RequestOptions.DEFAULT);
//同步執行 listener參考index的
client.msearchAsync(request, RequestOptions.DEFAULT, listener);
//MultiSearchResponse
MultiSearchResponse.Item firstResponse = response.getResponses()[0];
SearchResponse searchResponse = firstResponse.getResponse();
MultiSearchResponse.Item secondResponse = response.getResponses()[1];
searchResponse = secondResponse.getResponse();
}
SearchTemplate APIs介紹:
/**
* 查詢模板
* @throws Exception
*/
public void searchTemplate() throws Exception{
SearchTemplateRequest request = new SearchTemplateRequest();
request.setRequest(new SearchRequest("posts"));
//Inline Templates
request.setScriptType(ScriptType.INLINE);
//instead of providing an inline script
request.setScriptType(ScriptType.STORED);
request.setScript(
"{" +
" \"query\": { \"match\": { \"{{ field }}\": \"{{ value }}\" } }," +
" \"size\": \"{{ size }}\"" +
"}");
Map<String, Object> scriptParams = new HashMap<>();
scriptParams.put("field", "title");
scriptParams.put("value", "elasticsearch");
scriptParams.put("size", 5);
request.setScriptParams(scriptParams);
//同步執行
SearchTemplateResponse response = client.searchTemplate(request, RequestOptions.DEFAULT);
//異步執行 listener參考Index的
client.searchTemplateAsync(request, RequestOptions.DEFAULT, listener);
//SearchTemplate Response
SearchResponse searchResponse = response.getResponse();
BytesReference source = response.getSource();
}
Multi-SearchTemplate APIs介紹:
/**
* 多個查詢模板執行
* @throws Exception
*/
public void MultiSearchTemplate() throws Exception{
String[] searchTerms = {"elasticsearch", "logstash", "kibana"};
MultiSearchTemplateRequest multiRequest = new MultiSearchTemplateRequest();
for (String searchTerm: searchTerms) {
SearchTemplateRequest request = new SearchTemplateRequest();
request.setRequest(new SearchRequest("posts"));
request.setScriptType(ScriptType.INLINE);
request.setScript(
"{" +
" \"query\": { \"match\": { \"{{field}}\": \"{{value}}\" }}," +
" \"size\": \"{{size}}\"" +
"}"
);
Map<String, Object> scriptParams = new HashMap<>();
scriptParams.put("field", "title");
scriptParams.put("value", searchTerm);
scriptParams.put("size", 5);
request.setScriptParams(scriptParams);
multiRequest.add(request);
}
//同步執行
MultiSearchTemplateResponse multiResponse = client.msearchTemplate(multiRequest, RequestOptions.DEFAULT);
//異步執行
ActionListener<MultiSearchTemplateResponse> listener = new ActionListener<MultiSearchTemplateResponse>() {
@Override
public void onResponse(MultiSearchTemplateResponse response) {
}
@Override
public void onFailure(Exception e) {
}
};
client.msearchTemplateAsync(multiRequest, RequestOptions.DEFAULT, listener);
//MultiSearchTemplateResponse
for (MultiSearchTemplateResponse.Item item : multiResponse.getResponses()) {
if (item.isFailure()) {
String error = item.getFailureMessage();
} else {
SearchTemplateResponse searchTemplateResponse = item.getResponse();
SearchResponse searchResponse = searchTemplateResponse.getResponse();
searchResponse.getHits();
}
}
}
其餘APIs可以參考:https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high.html
4. Jest
Jest是第三方工具,是ElasticSearch的Java HTTP Rest客戶端。Jest填補了ElasticSearch缺少Http Rest接口客戶端的空白。
Jest的API爲:
Jest的具體用法參考:https://blog.csdn.net/u010466329/article/details/75020956/
Jest的代碼github地址:https://github.com/searchbox-io/Jest
5. Spring Data Elasticsearch
可參考https://blog.csdn.net/qq_33314107/article/details/80725994
6. 常見報錯
NoNodeAvailableException報錯,主要是外網IP沒有配置
在elasticSearch.yml上配置transport.host和transport.tcp.port即可
transport.host: localhost
transport.tcp.port: 9300
localhost可以是具體的IP地址
7. 總結
個人編寫的TransportClient和RestClient的github Demo:
https://github.com/SwordfallYeung/ElasticSearchDemo
參考資料:
https://www.elastic.co/guide/en/elasticsearch/client/index.html
https://www.elastic.co/guide/en/elasticsearch/client/java-rest/6.4/java-rest-overview.html
https://blog.csdn.net/qq_33314107/article/details/80725913