ElasticSearch: java API - 基本增删改查和聚合查询
ElasticSearch版本
elasticsearch-5.4.3.jar
指定 ip地址创建client
private TransportClient client = null;
/**
*指定 ip地址创建client
*/
@Before
public void init() throws Exception {
//设置集群名称
Settings settings = Settings.builder()
.put("cluster.name", "my-es")
//自动感知的功能（可以通过当前指定的节点获取所有es节点的信息）
.put("client.transport.sniff", true)
.build();
//创建client
client = new PreBuiltTransportClient(settings).addTransportAddresses(
// Java对应的API操作的端口都是9300，记住是9300
new InetSocketTransportAddress(InetAddress.getByName("192.168.100.211"), 9300),
new InetSocketTransportAddress(InetAddress.getByName("192.168.100.212"), 9300),
new InetSocketTransportAddress(InetAddress.getByName("192.168.100.213"), 9300));
}添加数据
/**
*添加数据
*/
@Test
public void testCreate() throws IOException {
// index可以理解为数据库；type理解为数据表；id相当于数据库表中记录的主键，是唯一的。
IndexResponse response = client.prepareIndex("gamelog", "users", "1")
.setSource(
jsonBuilder()
.startObject()
// field理解为列
.field("username", "老赵")
.field("gender", "male")
.field("birthday", new Date())
.field("fv", 9999)
.field("message", "trying out Elasticsearch")
.endObject()
).get();
}查找一条
/**
*查找一条
*/
@Test
public void testGet() throws IOException {
GetResponse response = client.prepareGet("gamelog", "users", "1").get();
System.out.println(response.getSourceAsString());
}查找多条
/**
* 查找多条
*/
@Test
public void testMultiGet() throws IOException {
MultiGetResponse multiGetItemResponses = client.prepareMultiGet()
.add("gamelog", "users", "1")
.add("gamelog", "users", "2", "3")
.add("news", "fulltext", "1")
.get();
for (MultiGetItemResponse itemResponse : multiGetItemResponses) {
GetResponse response = itemResponse.getResponse();
if (response.isExists()) {
String json = response.getSourceAsString();
System.out.println(json);
}
}
}
数据更新
/**
* 数据更新
*/
@Test
public void testUpdate() throws Exception {
UpdateRequest updateRequest = new UpdateRequest();
updateRequest.index("gamelog");
updateRequest.type("users");
updateRequest.id("2");
updateRequest.doc(
jsonBuilder()
.startObject()
.field("fv", 999.9)
.endObject());
client.update(updateRequest).get();
}数据删除-指定ID
/**
* 数据删除-指定ID
*/
@Test
public void testDelete() {
DeleteResponse response = client.prepareDelete("gamelog", "users", "2").get();
System.out.println(response);
}
数据删除--指定任意某个字段
/**
* 数据删除--指定任意某个字段
*/
@Test
public void testDeleteByQuery() {
BulkByScrollResponse response =
DeleteByQueryAction.INSTANCE.newRequestBuilder(client)
//指定查询条件
.filter(QueryBuilders.matchQuery("username", "老段"))
//指定索引名称
.source("gamelog")
.get();
long deleted = response.getDeleted();
System.out.println(deleted);
}异步删除
/**
* 异步删除
*/
@Test
public void testDeleteByQueryAsync() {
DeleteByQueryAction.INSTANCE.newRequestBuilder(client)
.filter(QueryBuilders.matchQuery("gender", "male"))
.source("gamelog")
.execute(new ActionListener() {
@Override
public void onResponse(BulkByScrollResponse response) {
long deleted = response.getDeleted();
System.out.println("数据删除了");
System.out.println(deleted);
}
@Override
public void onFailure(Exception e) {
e.printStackTrace();
}
});
try {
System.out.println("异步删除");
Thread.sleep(10000);
} catch (Exception e) {
e.printStackTrace();
}
} 范围查询
/**
* 范围查询
*/
@Test
public void testRange() {
QueryBuilder qb = rangeQuery("fv")
// [88.99, 10000)
.from(88.99)
.to(10000)
.includeLower(true)
.includeUpper(false);
SearchResponse response = client.prepareSearch("gamelog").setQuery(qb).get();
System.out.println(response);
}聚合查询
先添加一些数据
/**
* curl -XPUT 'http://192.168.5.251:9200/player_info/player/1' -d '{ "name": "curry", "age": 29, "salary": 3500,"team": "war", "position": "pg"}'
* curl -XPUT 'http://192.168.5.251:9200/player_info/player/2' -d '{ "name": "thompson", "age": 26, "salary": 2000,"team": "war", "position": "pg"}'
* curl -XPUT 'http://192.168.5.251:9200/player_info/player/3' -d '{ "name": "irving", "age": 25, "salary": 2000,"team": "cav", "position": "pg"}'
* curl -XPUT 'http://192.168.5.251:9200/player_info/player/4' -d '{ "name": "green", "age": 26, "salary": 2000,"team": "war", "position": "pf"}'
* curl -XPUT 'http://192.168.5.251:9200/player_info/player/5' -d '{ "name": "james", "age": 33, "salary": 4000,"team": "cav", "position": "sf"}'
*/ @Test
public void testAddPlayer() throws IOException {
IndexResponse response = client.prepareIndex("player_info", "player", "1")
.setSource(
jsonBuilder()
.startObject()
.field("name", "James")
.field("age", 33)
.field("salary", 3000)
.field("team", "cav")
.field("position", "sf")
.endObject()
).get();
}group by/count
例如要计算每个球队的球员数，如果使用SQL语句，应表达如下：
select team, count(*) as player_count from player group by team;ES的java api：
@Test
public void testAgg1() {
//指定索引和type
SearchRequestBuilder builder = client.prepareSearch("player_info").setTypes("player");
//按team分组然后聚合，但是并没有指定聚合函数
TermsAggregationBuilder teamAgg = AggregationBuilders.terms("player_count").field("team");
//添加聚合器
builder.addAggregation(teamAgg);
//触发
SearchResponse response = builder.execute().actionGet();
//System.out.println(response);
//将返回的结果放入到一个map中
Map aggMap = response.getAggregations().getAsMap();
// Set keys = aggMap.keySet();
//
// for (String key: keys) {
// System.out.println(key);
// }
// //取出聚合属性
StringTerms terms = (StringTerms) aggMap.get("player_count");
//
//// //依次迭代出分组聚合数据
// for (Terms.Bucket bucket : terms.getBuckets()) {
// //分组的名字
// String team = (String) bucket.getKey();
// //count，分组后一个组有多少数据
// long count = bucket.getDocCount();
// System.out.println(team + " " + count);
// }
Iterator teamBucketIt = terms.getBuckets().iterator();
while (teamBucketIt .hasNext()) {
Terms.Bucket bucket = teamBucketIt.next();
String team = (String) bucket.getKey();
long count = bucket.getDocCount();
System.out.println(team + " " + count);
}
} group by多个field
例如要计算每个球队每个位置的球员数，如果使用SQL语句，应表达如下：
select team, position, count(*) as pos_count from player group by team, position;ES的java api：
/**
* group by多个field
* 例如要计算每个球队每个位置的球员数，如果使用SQL语句
* select team, position, count(*) as pos_count from player group by team, position;
*/
@Test
public void testAgg2() {
SearchRequestBuilder builder = client.prepareSearch("player_info").setTypes("player");
//指定别名和分组的字段
TermsAggregationBuilder teamAgg = AggregationBuilders.terms("team_name").field("team");
TermsAggregationBuilder posAgg= AggregationBuilders.terms("pos_count").field("position");
//添加两个聚合构建器
builder.addAggregation(teamAgg.subAggregation(posAgg));
//执行查询
SearchResponse response = builder.execute().actionGet();
//将查询结果放入map中
Map aggMap = response.getAggregations().getAsMap();
//根据属性名到map中查找
StringTerms teams = (StringTerms) aggMap.get("team_name");
//循环查找结果
for (Terms.Bucket teamBucket : teams.getBuckets()) {
//先按球队进行分组
String team = (String) teamBucket.getKey();
Map subAggMap = teamBucket.getAggregations().getAsMap();
StringTerms positions = (StringTerms) subAggMap.get("pos_count");
//因为一个球队有很多位置，那么还要依次拿出位置信息
for (Terms.Bucket posBucket : positions.getBuckets()) {
//拿到位置的名字
String pos = (String) posBucket.getKey();
//拿出该位置的数量
long docCount = posBucket.getDocCount();
//打印球队，位置，人数
System.out.println(team + " " + pos + " " + docCount);
}
}
}
max/min/sum/avg
例如要计算每个球队年龄最大/最小/总/平均的球员年龄，如果使用SQL语句，应表达如下：
select team, max(age) as max_age from player group by team;ES的java api：
/**
* select team, max(age) as max_age from player group by team;
*/
@Test
public void testAgg3() {
SearchRequestBuilder builder = client.prepareSearch("player_info").setTypes("player");
//指定安球队进行分组
TermsAggregationBuilder teamAgg = AggregationBuilders.terms("team_name").field("team");
//指定分组求最大值
MaxAggregationBuilder maxAgg = AggregationBuilders.max("max_age").field("age");
//分组后求最大值
builder.addAggregation(teamAgg.subAggregation(maxAgg));
//查询
SearchResponse response = builder.execute().actionGet();
Map aggMap = response.getAggregations().getAsMap();
//根据team属性，获取map中的内容
StringTerms teams = (StringTerms) aggMap.get("team_name");
for (Terms.Bucket teamBucket : teams.getBuckets()) {
//分组的属性名
String team = (String) teamBucket.getKey();
//在将聚合后取最大值的内容取出来放到map中
Map subAggMap = teamBucket.getAggregations().getAsMap();
//取分组后的最大值
InternalMax ages = (InternalMax)subAggMap.get("max_age");
double max = ages.getValue();
System.out.println(team + " " + max);
}
}
对多个field求max/min/sum/avg
例如要计算每个球队球员的平均年龄，同时又要计算总年薪，如果使用SQL语句，应表达如下：
select team, avg(age)as avg_age, sum(salary) as total_salary from player group by team;ES的java api：
/**
* select team, avg(age) as avg_age, sum(salary) as total_salary from player group by team;
*/
@Test
public void testAgg4() {
SearchRequestBuilder builder = client.prepareSearch("player_info").setTypes("player");
//指定分组字段
TermsAggregationBuilder termsAgg = AggregationBuilders.terms("team_name").field("team");
//指定聚合函数是求平均数据
AvgAggregationBuilder avgAgg = AggregationBuilders.avg("avg_age").field("age");
//指定另外一个聚合函数是求和
SumAggregationBuilder sumAgg = AggregationBuilders.sum("total_salary").field("salary");
//分组的聚合器关联了两个聚合函数
builder.addAggregation(termsAgg.subAggregation(avgAgg).subAggregation(sumAgg));
SearchResponse response = builder.execute().actionGet();
Map aggMap = response.getAggregations().getAsMap();
//按分组的名字取出数据
StringTerms teams = (StringTerms) aggMap.get("team_name");
for (Terms.Bucket teamBucket : teams.getBuckets()) {
//获取球队名字
String team = (String) teamBucket.getKey();
Map subAggMap = teamBucket.getAggregations().getAsMap();
//根据别名取出平均年龄
InternalAvg avgAge = (InternalAvg)subAggMap.get("avg_age");
//根据别名取出薪水总和
InternalSum totalSalary = (InternalSum)subAggMap.get("total_salary");
double avgAgeValue = avgAge.getValue();
double totalSalaryValue = totalSalary.getValue();
System.out.println(team + " " + avgAgeValue + " " + totalSalaryValue);
}
}
聚合后对Aggregation结果排序
例如要计算每个球队总年薪，并按照总年薪倒序排列，如果使用SQL语句，应表达如下：
select team, sum(salary) as total_salary from player group by team order by total_salary desc;ES的java api：
/**
* select team, sum(salary) as total_salary from player group by team order by total_salary desc;
*/
@Test
public void testAgg5() {
SearchRequestBuilder builder = client.prepareSearch("player_info").setTypes("player");
//按team进行分组，然后指定排序规则
TermsAggregationBuilder termsAgg = AggregationBuilders.terms("team_name").field("team").order(Terms.Order.aggregation("total_salary ", true));
SumAggregationBuilder sumAgg = AggregationBuilders.sum("total_salary").field("salary");
builder.addAggregation(termsAgg.subAggregation(sumAgg));
SearchResponse response = builder.execute().actionGet();
Map aggMap = response.getAggregations().getAsMap();
StringTerms teams = (StringTerms) aggMap.get("team_name");
for (Terms.Bucket teamBucket : teams.getBuckets()) {
String team = (String) teamBucket.getKey();
Map subAggMap = teamBucket.getAggregations().getAsMap();
InternalSum totalSalary = (InternalSum)subAggMap.get("total_salary");
double totalSalaryValue = totalSalary.getValue();
System.out.println(team + " " + totalSalaryValue);
}
} 需要特别注意的是，排序是在TermAggregation处执行的，Order.aggregation函数的第一个参数是aggregation的名字，第二个参数是boolean型，true表示正序，false表示倒序。
- Aggregation结果条数的问题
默认情况下，search执行后，仅返回10条聚合结果，如果想反悔更多的结果，需要在构建TermsBuilder 时指定size：
TermsBuilder teamAgg= AggregationBuilders.terms("team").size(15);
- Aggregation结果的解析/输出
得到response后：
Map aggMap = response.getAggregations().asMap();
StringTerms teamAgg= (StringTerms) aggMap.get("keywordAgg");
Iterator teamBucketIt = teamAgg.getBuckets().iterator();
while (teamBucketIt .hasNext()) {
Bucket buck = teamBucketIt .next();
//球队名
String team = buck.getKey();
//记录数
long count = buck.getDocCount();
//得到所有子聚合
Map subaggmap = buck.getAggregations().asMap();
//avg值获取方法
double avg_age= ((InternalAvg) subaggmap.get("avg_age")).getValue();
//sum值获取方法
double total_salary = ((InternalSum) subaggmap.get("total_salary")).getValue();
//...
//max/min以此类推
}
- 总结
综上，聚合操作主要是调用了SearchRequestBuilder的addAggregation方法，通常是传入一个TermsBuilder，子聚合调用TermsBuilder的subAggregation方法，可以添加的子聚合有TermsBuilder、SumBuilder、AvgBuilder、MaxBuilder、MinBuilder等常见的聚合操作。
从实现上来讲，SearchRequestBuilder在内部保持了一个私有的 SearchSourceBuilder实例， SearchSourceBuilder内部包含一个List
同样的，TermsBuilder也在内部保持了一个List
参考来源：https://www.elastic.co/guide/en/elasticsearch/client/java-api/5.4/index.html
参考来源：https://elasticsearch.cn/article/102