初识elasticsearch_2(查询和整合springboot)
初始化
首先将官网所下载的json文件,放入到es中,采用如下命令:
curl -H "Content-Type: application/json" -XPOST 'localhost:9200/bank/account/_bulk?pretty&refresh' --data-binary "@accounts.json"
curl 'localhost:9200/_cat/indices?v'
search API
接下来可以开始查询啦.可以通过2种方式进行查询,分别为将其放在RESTAPI中或者将其放在RESTAPI的请求体中.显然请求体的形式更加具有代表性并且也更加易读/
先看放在RESTAPI中的,下面的语句查询出了bank索引的所有的文档.
GET /bank/_search?q=*&sort=account_number:asc&pretty
参数列表代表q=*查询所有,sort=account_number:asc,代表结果按照account_number升序排列,pretty代表将返回结果以格式化JSON的形式输出.
可以看看返回值,返回值说明写在注释里面:
{
"took" : 63,
// 是否延迟
"timed_out" : false,
// 当前搜索的有多少个shards
"_shards" : {
"total" : 5,
"successful" : 5,
"skipped" : 0,
"failed" : 0
},
// 搜索结果
"hits" : {
// 符合搜索结果的条数
"total" : 1000,
"max_score" : null,
// 结果的数组,默认显示前10条
"hits" : [ {
"_index" : "bank",
"_type" : "account",
"_id" : "0",
// 排序字段
"sort": [0],
"_score" : null,
"_source" : {"account_number":0,"balance":16623,"firstname":"Bradshaw","lastname":"Mckenzie","age":29,"gender":"F","address":"244 Columbus Place","employer":"Euron","email":"bradshawmckenzie@euron.com","city":"Hobucken","state":"CO"}
}, {
"_index" : "bank",
"_type" : "account",
"_id" : "1",
"sort": [1],
"_score" : null,
"_source" : {"account_number":1,"balance":39225,"firstname":"Amber","lastname":"Duke","age":32,"gender":"M","address":"880 Holmes Lane","employer":"Pyrami","email":"amberduke@pyrami.com","city":"Brogan","state":"IL"}
}, ...
]
}
}
可以采用请求体的方式去请求:
GET /bank/_search
{
"query": { "match_all": {} },
"sort": [
{ "account_number": "asc" }
]
}
返回的结果是一样的.
通过增加参数,可以控制返回的结果条数:
// 展示一条
GET /bank/_search
{
"query": { "match_all": {} },
"size": 1
}
// 第10条~第20条
GET /bank/_search
{
"query": { "match_all": {} },
"from": 10,
"size": 10
}
下面的是根据balance进行倒序排列
GET /bank/_search
{
"query": { "match_all": {} },
"sort": { "balance": { "order": "desc" } }
}
默认情况下,返回的source是包含所有的数据结构的,如果我们不想返回document的所有的数据结构,可以采用下面的语句:
GET /bank/_search
{
"query": { "match_all": {} },
"_source": ["account_number", "balance"]
}
可以看看返回值:
{
"took": 11,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 999,
"max_score": 1,
"hits": [
{
"_index": "bank",
"_type": "account",
"_id": "25",
"_score": 1,
"_source": {
"account_number": 25,
"balance": 40540
}
}
]
}
}
接下来可以看看根据字段过滤的,下面的筛选了account_number为20的订单
GET /bank/_search
{
"query": { "match": { "account_number": 20 } }
}
下面筛选出了地址值包含mill,lane的结果
GET /bank/_search
{
"query": { "match": { "address": "mill lane" } }
}
如果要筛选包含短语mill lane的呢:
GET /bank/_search
{
"query": { "match_phrase": { "address": "mill lane" } }
}
紧接着来看看bool查询.
以下bool查询和上面的查询是一样的,查询出包含短语包含短语mill lane的:
GET /bank/_search
{
"query": {
"bool": {
"must": [
{ "match": { "address": "mill" } },
{ "match": { "address": "lane" } }
]
}
}
}
Must代表所有的查询都必须返回true.再看看下面的语句:
GET /bank/_search
{
"query": {
"bool": {
"should": [
{ "match": { "address": "mill" } },
{ "match": { "address": "lane" } }
]
}
}
}
should代表这些查询中,当中的一个,必须返回true.
下面的语句,代表地址中既不能包含mill也不能包含lane:
GET /bank/_search
{
"query": {
"bool": {
"must_not": [
{ "match": { "address": "mill" } },
{ "match": { "address": "lane" } }
]
}
}
}
must_not要求查询结果对于所有的query都不满足
各个条件之间是可以相互组合的,如下:
GET /bank/_search
{
"query": {
"bool": {
"must": [
{ "match": { "age": "40" } }
],
"must_not": [
{ "match": { "state": "ID" } }
]
}
}
}
我们可以通过过滤器(filter)搜索banalance在20000到30000之间的东西
GET /bank/_search
{
"query": {
"bool": {
"must": { "match_all": {} },
"filter": {
"range": {
"balance": {
"gte": 20000,
"lte": 30000
}
}
}
}
}
}
注意,must中”match”是不支持gte和lte的.
分组,注意,es可以在额外返回一个aggressions的数组,可以通过参数说明对返回的数组进行分组.如下所示:
GET /bank/_search
{
"size": 0,
"aggs": {
"group_by_state": {
"terms": {
"field": "state.keyword"
}
}
}
}
上面的语句大概等同于如下SQL:
SELECT state, COUNT(*) FROM bank GROUP BY state ORDER BY COUNT(*) DESC
下面的语句计算了按照state分类后,balance的平均值
GET /bank/_search
{
"size": 0,
"aggs": {
"group_by_state": {
"terms": {
"field": "state.keyword"
},
"aggs": {
"average_balance": {
"avg": {
"field": "balance"
}
}
}
}
}
}
注意,我们使用了两次aggs,注意,当我们需要对结果进行操作的时候,我们可以使用aggs嵌套的方式去从返回值中提取需要的数据.
下面是一个演示aggs嵌套的例子:
GET /bank/_search
{
"size": 0,
"aggs": {
"group_by_age": {
"range": {
"field": "age",
"ranges": [
{
"from": 20,
"to": 30
},
{
"from": 30,
"to": 40
},
{
"from": 40,
"to": 50
}
]
},
"aggs": {
"group_by_gender": {
"terms": {
"field": "gender.keyword"
},
"aggs": {
"average_balance": {
"avg": {
"field": "balance"
}
}
}
}
}
}
}
}
这行语句的目的主要是先按照年龄段进行分组,在按照性别进行分组,最后取balance的平均值.返回值如下:
{
"took": 8,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 999,
"max_score": 0,
"hits": []
},
"aggregations": {
"group_by_age": {
"buckets": [
{
"key": "20.0-30.0",
"from": 20,
"to": 30,
"doc_count": 450,
"group_by_gender": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "M",
"doc_count": 231,
"average_balance": {
"value": 27400.982683982686
}
},
{
"key": "F",
"doc_count": 219,
"average_balance": {
"value": 25341.260273972603
}
}
]
}
},
{
"key": "30.0-40.0",
"from": 30,
"to": 40,
"doc_count": 504,
"group_by_gender": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "F",
"doc_count": 253,
"average_balance": {
"value": 25670.869565217392
}
},
{
"key": "M",
"doc_count": 251,
"average_balance": {
"value": 24288.239043824702
}
}
]
}
},
{
"key": "40.0-50.0",
"from": 40,
"to": 50,
"doc_count": 45,
"group_by_gender": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "M",
"doc_count": 24,
"average_balance": {
"value": 26474.958333333332
}
},
{
"key": "F",
"doc_count": 21,
"average_balance": {
"value": 27992.571428571428
}
}
]
}
}
]
}
}
}
springboot整合elasticsearch
由于springboot使用的是spring-data-elasticsearch,但是目前这个最高版本对应的es版本没有到5,因此我们使用较低的es版本进行测试.采用的es版本是2.3.2,对应的spring-data-elasticsearch版本为2.1.0,spring-boot版本采用1.5.1,springboot-starter-elasticsearch版本为1.5.1.RELEASE
- pom.xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-elasticsearch</artifactId>
<version>1.5.1.RELEASE</version>
</dependency>
- application.properties
# ES
spring.data.elasticsearch.repositories.enabled = true
spring.data.elasticsearch.cluster-nodes = 127.0.0.1:9300
- 实体类(Account)
需要注意的是,indexName,type都不能有大写.否则会报错
@Document(indexName = "bank",type = "account")
public class Account implements Serializable{
@Id
private Long id;
private Integer account_number;
private Long balance;
private String firstname;
private String lastname;
private Integer age;
private String gender;
private String address;
private String employer;
private String email;
private String city;
private String state;
// get&set
}
- 操作es的repository
非常简单只需要继承即可.
public interface AccountRepository extends ElasticsearchRepository<Account,Long> {
}
- service
需要注意的是,在保存的时候,当文档对应的索引没有的时候,es会为我们手动创建,在保存文档的时候需要手动指定id,否则es会将null作为文档的id.
@Service
public class AccountServiceEsImpl {
@Autowired AccountRepository accountRepository;
/**
* 保存账号
*/
public Long save(Account account) {
Account acountSaved = accountRepository.save(account);
return acountSaved.getId();
}
/**
* 根据地址值过滤
* @return
*/
public List<Account> queryByAddress() {
// 根据地址值过滤
Pageable page = new PageRequest(0,10);
BoolQueryBuilder queryBuilder = QueryBuilders.boolQuery();
queryBuilder.must(QueryBuilders.matchQuery("address","Beijing"));
SearchQuery query =
new NativeSearchQueryBuilder().withQuery(queryBuilder).withPageable(page).build();
Page<Account> pages = accountRepository.search(query);
return pages.getContent();
}
}
加油
