es查询-Java API

有Low Level REST Client和High Level REST Client。

Low Level REST Client需要自己拼接所有的语句，需要自己解析结果。

High Level REST Client基于 Low Level REST Client。

pom如下。

<dependencies>
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>7.3.0</version>
<exclusions>
<exclusion>
<groupId>org.elasticsearch</groupId>
<artifactId>elasticsearch</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.elasticsearch</groupId>
<artifactId>elasticsearch</artifactId>
<version>7.3.0</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.testng</groupId>
<artifactId>testng</artifactId>
<version>6.14.3</version>
<scope>test</scope>
</dependency>
</dependencies>

准备日志配置文件
resource目录下创建：log4j2.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{yyyy-mm-dd HH:mm:ss} [%t] %-5p %c{1}:%L - %msg%n" />
</Console>
</Appenders>
<Loggers>
<Root level="info">
<AppenderRef ref="Console" />
</Root>
</Loggers>
</Configuration>

样例:

RestHighLevelClient client;
//准备一个highlevel client
@Before
public void init() {
final RestHighLevelClient highLevelClient = new
RestHighLevelClient(RestClient.builder(
new HttpHost("linux121", 9200, "http"),
new HttpHost("linux122", 9200, "http"),
new HttpHost("linux123", 9200, "http")
));
// System.out.println(highLevelClient.cluster().toString());
client = highLevelClient;
}
@After
public void destory() {
if (client != null) {
try {
client.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

索引操作

//创建索引
@Test
public void createIndex() {
final CreateIndexRequest indexRequest = new CreateIndexRequest("es_test");
//准备mapping映射信息
String str = "{\n" +
" \"settings\": {},\n" +
" \"mappings\": {\n" +
" \"properties\": {\n" +
" \"description\": {\n" +
" \"type\": \"text\",\n" +
" \"analyzer\": \"ik_max_word\"\n" +
" },\n" +
" \"name\": {\n" +
" \"type\": \"text\"\n" +
" },\n" +
" \"pic\": {\n" +
" \"type\": \"text\",\n" +
" \"index\": false\n" +
" },\n" +
" \"studymodel\": {\n" +
" \"type\": \"text\"\n" +
" }\n" +
" }\n" +
" }\n" +
" }";
//把映射信息添加到request对象中
indexRequest.source(str, XContentType.JSON);
//创建索引
try {
final CreateIndexResponse createIndexResponse =
client.indices().create(indexRequest, RequestOptions.DEFAULT);
final boolean acknowledged = createIndexResponse.isAcknowledged();
System.out.println("创建结果：" + acknowledged);
} catch (IOException e) {
e.printStackTrace();
}
}

indexRequest.settings(
Settings.builder()
.put("index.number_of_shards", 5)
.put("index.number_of_replicas", 1)
);
//指定mapping信息
final XContentBuilder xContentBuilder = XContentFactory.jsonBuilder();
xContentBuilder.startObject();
xContentBuilder.startObject("properties");
xContentBuilder.startObject("description")
.field("type", "text")
.field("analyzer", "ik_max_word")
.endObject();
xContentBuilder.startObject("name")
.field("type", "text")
.endObject();
xContentBuilder.startObject("pic")
.field("type", "text")
.field("index", "false")
.endObject();
xContentBuilder.startObject("studymodel")
.field("type", "text")
.endObject();
xContentBuilder.endObject();
xContentBuilder.endObject();
indexRequest.mapping(xContentBuilder);
//创建索引
try {
final CreateIndexResponse createIndexResponse =
client.indices().create(indexRequest, RequestOptions.DEFAULT);
final boolean acknowledged = createIndexResponse.isAcknowledged();
System.out.println("创建结果：" + acknowledged);
} catch (IOException e) {
e.printStackTrace();
}
}

//删除索引
@Test
public void deleteIndex() throws IOException {
//创建一个删除索引的请求
final DeleteIndexRequest indexRequest = new DeleteIndexRequest("es_test");
final AcknowledgedResponse delete = client.indices().delete(indexRequest,
RequestOptions.DEFAULT);
System.out.println(delete.isAcknowledged());
}

文档操作

//添加doc
@Test
public void addDoc() throws IOException {
//准备一个添加文档的对象
final IndexRequest indexRequest = new IndexRequest("es_test").id("1");
/*
{
"name": "spark添加文档",
"description": "spark技术栈",
"studymodel":"online",
"pic": "http://www.baidu.com"
}
*/
//准备文档内容
String str = " {\n" +
" \"name\": \"spark添加文档\",\n" +
" \"description\": \"spark技术栈\",\n" +
" \"studymodel\":\"online\",\n" +
" \"pic\": \"http://www.baidu.com\"\n" +
" }";
indexRequest.source(str, XContentType.JSON);
//执行添加动作
final IndexResponse index = client.index(indexRequest, RequestOptions.DEFAULT);
System.out.println(index.status());
}



//查询文档
@Test
public void getDoc() throws IOException {
//准备一个查询的reqeust请求
final GetRequest getRequest = new GetRequest("es_test");
//设定id he
getRequest.id("1");
//执行查询
final GetResponse getResponse = client.get(getRequest, RequestOptions.DEFAULT);
final Map<String, Object> sourceAsMap = getResponse.getSourceAsMap();
System.out.println(sourceAsMap);
}


//查询所有文档
@Test
public void getAllDoc() throws IOException {
// 构建一个searchRequest对象
final SearchRequest searchRequest = new SearchRequest();
//指定索引
searchRequest.indices("es_test");
//指定查询条件 matchall
final SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder.query(QueryBuilders.matchAllQuery());
searchRequest.source(sourceBuilder);
//执行检索 RequestOptions options参数: 请求选项(例如请求头),如果不需要自定义任何内容,使用
RequestOptions.DEFAULT
final SearchResponse response = client.search(searchRequest,
RequestOptions.DEFAULT);
//解析响应结果
final RestStatus status = response.status();
System.out.println("查询结果状态：" + status);
final SearchHits hits = response.getHits();
final SearchHit[] hits1 = hits.getHits();
for (SearchHit searchHit : hits1) {
System.out.println("----------------------------");
final Map<String, Object> map = searchHit.getSourceAsMap();
for (Map.Entry<String, Object> entry : map.entrySet()) {
System.out.println("查询的字段：" + entry.getKey() + "; 字段value:" +
entry.getValue());
}
}
}

//termquery
@Test
public void termQuery() throws IOException {
//根据关键字 不分词检索
final SearchRequest searchRequest = new SearchRequest("es_test");
//sourcebuilder
final SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
//指定检索的类型
sourceBuilder.query(QueryBuilders.termQuery("studymodel", "online"));
//添加sourcebuilder
searchRequest.source(sourceBuilder);
//执行查询
final SearchResponse response = client.search(searchRequest,
RequestOptions.DEFAULT);
//解析response
final RestStatus status = response.status();
System.out.println("查询结果状态：" + status);
final SearchHits hits = response.getHits();
final SearchHit[] hits1 = hits.getHits();
for (SearchHit searchHit : hits1) {
System.out.println("----------------------------");
final Map<String, Object> map = searchHit.getSourceAsMap();
for (Map.Entry<String, Object> entry : map.entrySet()) {
System.out.println("查询的字段：" + entry.getKey() + "; 字段value:" +
entry.getValue());
}
}
}
//分页查询
@Test
public void getAllDocWithPage() throws IOException {
// 构建一个searchRequest对象
final SearchRequest searchRequest = new SearchRequest();
//指定索引
searchRequest.indices("es_test");
//指定查询条件 matchall
final SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder.query(QueryBuilders.matchAllQuery());
//指定分页
sourceBuilder.from(0);
sourceBuilder.size(1);
searchRequest.source(sourceBuilder);
//执行检索 RequestOptions options参数: 请求选项(例如请求头),如果不需要自定义任何内容,使用
RequestOptions.DEFAULT
final SearchResponse response = client.search(searchRequest,
RequestOptions.DEFAULT);
//解析响应结果
final RestStatus status = response.status();
System.out.println("查询结果状态：" + status);
final SearchHits hits = response.getHits();
final SearchHit[] hits1 = hits.getHits();
for (SearchHit searchHit : hits1) {
System.out.println("----------------------------");
final Map<String, Object> map = searchHit.getSourceAsMap();
for (Map.Entry<String, Object> entry : map.entrySet()) {
System.out.println("查询的字段：" + entry.getKey() + "; 字段value:" +
entry.getValue());
}
}
}
//对返回的source字段进行过滤
@Test
public void searchWithLimit() throws IOException {
// 构建一个searchRequest对象
final SearchRequest searchRequest = new SearchRequest();
//指定索引
searchRequest.indices("es_test");
//指定查询条件 matchall
final SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder.query(QueryBuilders.matchAllQuery());
//准备两个数组，包含，不包含
final String[] includesArr = {"name"};
final String[] excludesArr = {};
sourceBuilder.fetchSource(includesArr, excludesArr);
searchRequest.source(sourceBuilder);
//执行检索 RequestOptions options参数: 请求选项(例如请求头),如果不需要自定义任何内容,使用
RequestOptions.DEFAULT
final SearchResponse response = client.search(searchRequest,
RequestOptions.DEFAULT);
//解析响应结果
final RestStatus status = response.status();
System.out.println("查询结果状态：" + status);
final SearchHits hits = response.getHits();
final SearchHit[] hits1 = hits.getHits();
for (SearchHit searchHit : hits1) {
System.out.println("----------------------------");
final Map<String, Object> map = searchHit.getSourceAsMap();
for (Map.Entry<String, Object> entry : map.entrySet()) {
System.out.println("查询的字段：" + entry.getKey() + "; 字段value:" +
entry.getValue());
}
}
}


// 排序 sort
@Test
public void searchWithSort() throws IOException {
// 构建一个searchRequest对象
final SearchRequest searchRequest = new SearchRequest();
//指定索引
searchRequest.indices("book");
//指定查询条件 matchall
final SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
//指定排序规则
sourceBuilder.sort(new FieldSortBuilder("price").order(SortOrder.DESC));
sourceBuilder.query(QueryBuilders.matchAllQuery());
searchRequest.source(sourceBuilder);
//执行检索 RequestOptions options参数: 请求选项(例如请求头),如果不需要自定义任何内容,使用
RequestOptions.DEFAULT
final SearchResponse response = client.search(searchRequest,
RequestOptions.DEFAULT);
//解析响应结果
final RestStatus status = response.status();
System.out.println("查询结果状态：" + status);
final SearchHits hits = response.getHits();
final SearchHit[] hits1 = hits.getHits();
for (SearchHit searchHit : hits1) {
System.out.println("----------------------------");
final Map<String, Object> map = searchHit.getSourceAsMap();
for (Map.Entry<String, Object> entry : map.entrySet()) {
System.out.println("查询的字段：" + entry.getKey() + "; 字段value:" +
entry.getValue());
}
}
}


//聚合分析
//按照name分组，对组内计算一个avg的price
@Test
public void searchAgg() throws IOException {
// 构建一个searchRequest对象
final SearchRequest searchRequest = new SearchRequest();
//指定索引
searchRequest.indices("book");
//指定查询条件 matchall
final SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
//指定聚合分析的规则
final TermsAggregationBuilder aggregationBuilder =
AggregationBuilders.terms("name_group").field("name");
aggregationBuilder.subAggregation(AggregationBuilders.avg("avg_price").field("price"));
sourceBuilder.aggregation(aggregationBuilder);
searchRequest.source(sourceBuilder);
//执行检索 RequestOptions options参数: 请求选项(例如请求头),如果不需要自定义任何内容,使用
RequestOptions.DEFAULT
final SearchResponse searchResponse = client.search(searchRequest,
RequestOptions.DEFAULT);
//解析响应结果
final Terms name_group = searchResponse.getAggregations().get("name_group");
for (Terms.Bucket bucket : name_group.getBuckets()) {
final Object key = bucket.getKey();
final Avg avg_price = bucket.getAggregations().get("avg_price");
System.out.println("name：" + key + ",平均价格：" + avg_price.getValue());
}
}

Fielddata is disabled on text fields by default. Set `fielddata=true` on[`your_field_name`] in order to load fielddata in memory by uninverting theinverted index. Note that this can however use significant memory.

https://www.elastic.co/guide/en/elasticsearch/reference/current/fielddata.html