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elasticsearch是一款非常强大的开源搜索引擎,可以帮助我们从海量数据中快速找到需要的内容。
elasticsearch结合kibana、Logstash、Beats,也就是elastic stack(ELK)。被广泛应用在日志数据分析、实时监控等领域。
数据可视化和数据抓取的技术是可替换的,只有es不可替换
elasticsearch具备下列优势:
支持分布式,可水平扩展
提供Restful接口,可被任何语言调用
以mysql为例的正向索引
倒排索引
详见CSDN中其他文章
mapping是对索引库中文档的约束,常见的mapping属性包括:
# 索引库映射 PUT /heima { "mappings": { "properties": { "info": { "type": "text", "analyzer": "ik_smart" }, "email": { "type": "keyword", "index": false }, "name": { "properties": { "firstName": { "type": "keyword" }, "lastName": { "type": "keyword" } } } } } }
# 查看删除索引库
GET /heima
# 修改索引库-添加新字段
PUT /heima/_mapping
{
"properties": {
"age": {
"type":"integer"
}
}
}
# 插入文档
POST /heima/_doc/1
{
"info": "黑马程序员java讲师",
"email": "zy@itcast.cn",
"name": {
"firstName":"云",
"lastName" :"赵"
},
"age": 20
}
}
# 查询文档
GET /heima/_doc/1
{ "_index" : "heima", "_type" : "_doc", "_id" : "1", "_version" : 3, "_seq_no" : 2, "_primary_term" : 5, "found" : true, "_source" : { "info" : "黑马程序员java讲师", "email" : "zy@itcast.cn", "name" : { "firstName" : "云", "lastName" : "赵" }, "age" : 20 } }
#删除文档
DELETE /heima/_doc/1
{
"_index" : "heima",
"_type" : "_doc",
"_id" : "1",
"_version" : 4,
"result" : "deleted",
"_shards" : {
"total" : 2,
"successful" : 1,
"failed" : 0
},
"_seq_no" : 3,
"_primary_term" : 5
}
再次查询
# 全量修改
PUT /heima/_doc/1
{
"info": "黑马程序员java讲师",
"email": "ZhaoYun@itcast.cn",
"name": {
"firstName": "云",
"lastName": "赵"
},
"age": 20
}
{
"_index" : "heima",
"_type" : "_doc",
"_id" : "1",
"_version" : 4,
"result" : "updated",
"_shards" : {
"total" : 2,
"successful" : 1,
"failed" : 0
},
"_seq_no" : 7,
"_primary_term" : 5
}
# 增量修改
POST /heima/_update/1
{
"doc":{
"email": "ZYun@itcast.cn"
}
}
{
"_index" : "heima",
"_type" : "_doc",
"_id" : "1",
"_version" : 5,
"result" : "updated",
"_shards" : {
"total" : 2,
"successful" : 1,
"failed" : 0
},
"_seq_no" : 8,
"_primary_term" : 5
}
只显示前十条
#查看酒店文档
GET /hotel/_search
{ "took" : 1, "timed_out" : false, "_shards" : { "total" : 1, "successful" : 1, "skipped" : 0, "failed" : 0 }, "hits" : { "total" : { "value" : 201, "relation" : "eq" }, "max_score" : 1.0, "hits" : [ { "_index" : "hotel", "_type" : "_doc", "_id" : "36934", "_score" : 1.0, "_source" : { "address" : "静安交通路40号", "brand" : "7天酒店", "business" : "四川北路商业区", "city" : "上海", "id" : 36934, "location" : "31.251433, 121.47522", "name" : "7天连锁酒店(上海宝山路地铁站店)", "pic" : "https://m.tuniucdn.com/fb2/t1/G1/M00/3E/40/Cii9EVkyLrKIXo1vAAHgrxo_pUcAALcKQLD688AAeDH564_w200_h200_c1_t0.jpg", "price" : 336, "score" : 37, "starName" : "二钻" } }, 。。。
#查看酒店文档
GET /hotel/_search?q=name:上海
hotel
索引中搜索包含在"name"字段中包含"上海"的文档
{ "took" : 1, "timed_out" : false, "_shards" : { "total" : 1, "successful" : 1, "skipped" : 0, "failed" : 0 }, "hits" : { "total" : { "value" : 82, "relation" : "eq" }, "max_score" : 1.1531773, "hits" : [ { "_index" : "hotel", "_type" : "_doc", "_id" : "339777429", "_score" : 1.1531773, "_source" : { "address" : "菊园新区嘉唐公路66号", "brand" : "喜来登", "business" : "嘉定新城", "city" : "上海", "id" : 339777429, "location" : "31.394595, 121.245773", "name" : "上海嘉定喜来登酒店", "pic" : "https://m.tuniucdn.com/fb3/s1/2n9c/2v2fKuo5bzhunSBC1n1E42cLTkZV_w200_h200_c1_t0.jpg", "price" : 1286, "score" : 44, "starName" : "五钻" } }, 。。。
ES官方提供了各种不同语言的客户端,用来操作ES。这些客户端的本质就是组装DSL语句,通过http请求发送给ES。
hotel-demo中的application.yaml
server: port: 8089 spring: datasource: url: jdbc:mysql://mysql:3306/heima?useSSL=false username: root password: 123sjbsjb driver-class-name: com.mysql.jdbc.Driver logging: level: cn.itcast: debug pattern: dateformat: MM-dd HH:mm:ss:SSS mybatis-plus: configuration: map-underscore-to-camel-case: true type-aliases-package: cn.itcast.hotel.pojo
#酒店的mapping PUT /hotel { "mappings":{ "properties": { "id": { "type": "keyword", "copy_to": "all" }, "name":{ "type": "text", "analyzer": "ik_max_word" }, "address":{ "type": "keyword", "index":false }, "price":{ "type": "integer" }, "score":{ "type": "integer" }, "brand":{ "type": "keyword", "copy_to": "all" }, "city":{ "type": "keyword" }, "starName":{ "type": "keyword" }, "business":{ "type": "keyword", "copy_to": "all" }, "location":{ "type": "geo_point" }, "pic":{ "type": "keyword", "index":false }, "all":{ "type": "text", "analyzer": "ik_max_word" } } } }
1.引入es的RestHighLevelCLient依赖:
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
</dependency>
2.因为SpringBoot默认的ES版本是7.6.2,所以我们需要覆盖默认的ES版本:
<properties>
<java.version>1.8</java.version>
<elasticsearch.version>7.12.1</elasticsearch.version>
</properties>
3.初始化RestHighLevelClient:
在test/java/cn.itcast/hotel下创建HotelIndexTest
使用**@BeforeEach和@AfterEach**可以在测试方法前创建对象
public class HotelIndexTest { private RestHighLevelClient client; @Test public void testCreateIndex() { System.out.println(client); } //提前初始化RestHighLevelClient @BeforeEach public void setUp() { this.client = new RestHighLevelClient(RestClient.builder( HttpHost.create("http://192.168.204.129:9200")) ); } //销毁 @ public void tearDown() { try { client.close(); } catch (Exception e) { e.printStackTrace(); } } }
创建索引库代码
@Test
void testCreateHotelIndex() {
//1.创建Request对象
CreateIndexRequest request = new CreateIndexRequest("hotel");
//2.请求参数,MAPPING_TEMPLATE是静态常量字符串,内容是创建索引库的DSL语句
request.source(MAPPING_TEMPLATE, XContentType.JSON);
//3.发起请求
try {
client.indices().create(request, RequestOptions.DEFAULT);
} catch (IOException e) {
e.printStackTrace();
}
}
其中MAPPING_TEMPLATE是个静态常量,在cn.itcast.hotel下创建constants.HotelConstants,其中是对数据中的索引库创建的语句
public class HotelConstants { public static final String MAPPING_TEMPLATE="{\n" + " \"mappings\":{\n" + " \"properties\": {\n" + " \"id\": {\n" + " \"type\": \"keyword\",\n" + " \"copy_to\": \"all\"\n" + " },\n" + " \"name\":{\n" + " \"type\": \"text\",\n" + " \"analyzer\": \"ik_max_word\"\n" + " },\n" + " \"address\":{\n" + " \"type\": \"keyword\",\n" + " \"index\":false\n" + " },\n" + " \"price\":{\n" + " \"type\": \"integer\"\n" + " },\n" + " \"score\":{\n" + " \"type\": \"integer\"\n" + " },\n" + " \"brand\":{\n" + " \"type\": \"keyword\",\n" + " \"copy_to\": \"all\"\n" + " },\n" + " \"city\":{\n" + " \"type\": \"keyword\"\n" + " },\n" + " \"starName\":{\n" + " \"type\": \"keyword\"\n" + " },\n" + " \"business\":{\n" + " \"type\": \"keyword\",\n" + " \"copy_to\": \"all\"\n" + " },\n" + " \"location\":{\n" + " \"type\": \"geo_point\"\n" + " },\n" + " \"pic\":{\n" + " \"type\": \"keyword\",\n" + " \"index\":false\n" + " },\n" + " \"all\":{\n" + " \"type\": \"text\",\n" + " \"analyzer\": \"ik_max_word\"\n" + " }\n" + " }\n" + " }\n" + "}"; }
查看索引库
#查看酒店索引库
GET /hotel
{ "hotel" : { "aliases" : { }, "mappings" : { "properties" : { "address" : { "type" : "keyword", "index" : false }, "all" : { "type" : "text", "analyzer" : "ik_max_word" }, "brand" : { "type" : "keyword", "copy_to" : [ "all" ] }, "business" : { "type" : "keyword", "copy_to" : [ "all" ] }, "city" : { "type" : "keyword" }, "id" : { "type" : "keyword", "copy_to" : [ "all" ] }, "location" : { "type" : "geo_point" }, "name" : { "type" : "text", "analyzer" : "ik_max_word" }, "pic" : { "type" : "keyword", "index" : false }, "price" : { "type" : "integer" }, "score" : { "type" : "integer" }, "starName" : { "type" : "keyword" } } }, "settings" : { "index" : { "routing" : { "allocation" : { "include" : { "_tier_preference" : "data_content" } } }, "number_of_shards" : "1", "provided_name" : "hotel", "creation_date" : "1708945726260", "number_of_replicas" : "1", "uuid" : "4L8tS8p4QqGUJrYqWZGozQ", "version" : { "created" : "7120199" } } } } }
删除索引库
//删除索引库
@Test
void testDeleteHotelIndex() {
//1.创建Request对象
DeleteIndexRequest request = new DeleteIndexRequest("hotel");
//2.发起请求
try {
client.indices().delete(request, RequestOptions.DEFAULT);
} catch (IOException e) {
e.printStackTrace();
}
}
判断索引库是否存在
//判断索引库是否存在
@Test
void testExistHotelIndex() {
//1.创建Request对象
GetIndexRequest request = new GetIndexRequest("hotel");
//2.发起请求
try {
boolean exists = client.indices().exists(request, RequestOptions.DEFAULT);
System.err.println(exists?"索引库存在":"索引库不存在");
} catch (IOException e) {
e.printStackTrace();
}
}
在测试类中创建HotelDocumentIndexTest
public class HotelIndexTest { private RestHighLevelClient client; @Test public void testCreateIndex() { System.out.println(client); } //提前初始化RestHighLevelClient @BeforeEach public void setUp() { this.client = new RestHighLevelClient(RestClient.builder( HttpHost.create("http://192.168.204.129:9200")) ); } //销毁 @ public void tearDown() { try { client.close(); } catch (Exception e) { e.printStackTrace(); } } }
先查询酒店数据,然后给这条数据创建倒排索引,即可完成添加
采用mp的写法,注入IHotelService hotelService,之后用hotelService访问数据库
@SpringBootTest public class HotelDocumentIndexTest { @Autowired private IHotelService hotelService; private RestHighLevelClient client; @Test public void testCreateIndex() { System.out.println(client); } //添加文档 @Test void testAddIndexDocument() throws IOException { //根据ID查询 Hotel hotel = hotelService.getById(61083L); //转换为文档类型 HotelDoc hotelDoc = new HotelDoc(hotel); //1.创建Request对象 IndexRequest request = new IndexRequest("hotel").id(hotel.getId().toString()); //2.准备JSON文档 request.source(JSON.toJSONString(hotelDoc), XContentType.JSON); //3.发起请求 client.index(request, RequestOptions.DEFAULT); } //提前初始化RestHighLevelClient。。。 //销毁。。。 }
插入后查看
#查看酒店文档
GET /hotel/_doc/61083
{ "_index" : "hotel", "_type" : "_doc", "_id" : "61083", "_version" : 1, "_seq_no" : 0, "_primary_term" : 1, "found" : true, "_source" : { "address" : "自由贸易试验区临港新片区南岛1号", "brand" : "皇冠假日", "business" : "滴水湖临港地区", "city" : "上海", "id" : 61083, "location" : "30.890867, 121.937241", "name" : "上海滴水湖皇冠假日酒店", "pic" : "https://m.tuniucdn.com/fb3/s1/2n9c/312e971Rnj9qFyR3pPv4bTtpj1hX_w200_h200_c1_t0.jpg", "price" : 971, "score" : 44, "starName" : "五钻" } }
因为查询到的文档是json,所以需要反序列化成java对象
//查询文档
@Test
void testFindIndexDocument() throws IOException {
//1.创建Request对象
GetRequest request = new GetRequest("hotel","61083");
//2.发起请求
GetResponse response = client.get(request, RequestOptions.DEFAULT);
//3.发起请求
String json= response.getSourceAsString();
HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
System.out.println(hotelDoc);
}
HotelDoc(id=61083, name=上海滴水湖皇冠假日酒店, address=自由贸易试验区临港新片区南岛1号, price=971, score=44, brand=皇冠假日, city=上海, starName=五钻, business=滴水湖临港地区, location=30.890867, 121.937241, pic=https://m.tuniucdn.com/fb3/s1/2n9c/312e971Rnj9qFyR3pPv4bTtpj1hX_w200_h200_c1_t0.jpg)
//局部更新
@Test
void testUpdateIndexDocument() throws IOException {
//1.创建Request对象
UpdateRequest request = new UpdateRequest("hotel","61083");
//2.准备JSON文档
request.doc(
"price","952",
"starName","四钻"
);
//3.发起请求
client.update(request, RequestOptions.DEFAULT);
}
HotelDoc(id=61083, name=上海滴水湖皇冠假日酒店, address=自由贸易试验区临港新片区南岛1号, price=952, score=44, brand=皇冠假日, city=上海, starName=四钻, business=滴水湖临港地区, location=30.890867, 121.937241, pic=https://m.tuniucdn.com/fb3/s1/2n9c/312e971Rnj9qFyR3pPv4bTtpj1hX_w200_h200_c1_t0.jpg)
//删除酒店数据
@Test
void testDeleteIndexDocument() throws IOException {
//1.创建Request对象
DeleteRequest request = new DeleteRequest("hotel","61083");
//2.发起请求
client.delete(request, RequestOptions.DEFAULT);
}
每次添加发送请求
//批量导入酒店数据 @Test void testBatchInsertIndexDocument(){ //查询所有酒店数据 hotelService.list().forEach(hotel -> { //转换为文档类型 HotelDoc hotelDoc = new HotelDoc(hotel); //1.创建Request对象 IndexRequest request = new IndexRequest("hotel").id(hotel.getId().toString()); //2.准备JSON文档 request.source(JSON.toJSONString(hotelDoc), XContentType.JSON); //3.发起请求 try { client.index(request, RequestOptions.DEFAULT); } catch (IOException e) { e.printStackTrace(); } }); }
利用bulk发起请求
//批量导入数据利用client的bulk方法 @Test void testBatchInsertIndexDocument2() throws IOException { //1.创建BulkRequest对象 BulkRequest request = new BulkRequest(); //2.准备数据,添加到BulkRequest对象中 //查询所有酒店数据 hotelService.list().forEach(hotel -> { //转换为文档类型 HotelDoc hotelDoc = new HotelDoc(hotel); //3.添加到BulkRequest对象中 request.add(new IndexRequest("hotel") .id(hotel.getId().toString()) .source(JSON.toJSONString(hotelDoc), XContentType.JSON)); }); //4.发起请求 client.bulk(request, RequestOptions.DEFAULT); }
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