Elasticsearch Java API简介

本文介绍如何通过Java API操作Elasticsearch,包括创建项目、配置连接、执行查询及统计等常见操作,并提供多个代码示例。

Elasticsearch Java API简介

1、创建项目

  创建Maven项目添加依赖,依赖版本与ES服务版本一致:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.dameng.log</groupId>
    <artifactId>restLog</artifactId>
    <packaging>war</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>restLog Maven Webapp</name>
    <url>http://maven.apache.org</url>

    <repositories>
        <repository>
            <id>elasticsearch-releases</id>
            <url>https://artifacts.elastic.co/maven</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>x-pack-transport</artifactId>
            <version>5.4.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.8.2</version>
        </dependency>
    </dependencies>
    <build>
        <finalName>restLog</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

  值得注意的是,如果ES安装了x-pack插件,在链接ES服务时需要使用 PreBuiltXPackTransportClient ,该类在x-pack-transport包中,这个包在Maven的公共库里是没有的,需要添加ES的库。

2、ES基本配置与连接

2.1、基本配置

  ES有两种连接方式: Connecting a Client to a Coordinating Only NodeTransport Client ,本文使用的是后者,基本配置内容如下:

# Elasticsearch configuration

# ES的集群名称
cluster.name = elasticsearch
# 是否发现集群中的其他节点
client.transport.sniff = true
# 如果安装的x-pack插件,此处填写ES的用户名和密码
xpack.security.user = elastic:changeme
# 链接ES节点地址
transportAddress = localhost:9300

# 默认时区,用于查询时的日期比较
default.timeZone = Asia/Shanghai
# 默认返回页大小
default.size = 100
# 默认返回起始位置
default.from = 0

2.2、建立连接

  建立client的代码如下:

package com.dameng.es;

import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.InetSocketTransportAddress;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.elasticsearch.xpack.client.PreBuiltXPackTransportClient;

import java.io.IOException;
import java.io.InputStream;
import java.net.InetAddress;
import java.util.*;

/**
 * Created by lion on 2017/7/24.
 */
public class ESUtil {

    private static volatile TransportClient client = null;

    private static String timeZone = "";

    public static String getDefaultTimeZone() {
        return timeZone;
    }

    public static String getDefaultSize() {
        try {
            return ESUtil.getProperties().getProperty("default.size", "100");
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "100";
    }

    public static String getDefaultFrom() {
        try {
            return ESUtil.getProperties().getProperty("default.from", "0");
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "0";
    }

    private ESUtil () {

    }

    /**
     * 读取配置文件
     * @return
     * @throws IOException
     */
    private static Properties getProperties() throws IOException {
        try (InputStream inputStream = ESUtil.class.getClassLoader().getResourceAsStream("ES.properties")) {
            Properties properties = new Properties();
            properties.load(inputStream);
            return properties;
        }
    }

    /**
     * 获取ES客户端,单例实现
     * @return
     */
    public static TransportClient getClient() throws Exception {
        if (ESUtil.client == null) {
            Properties properties = ESUtil.getProperties();
            Settings.Builder builder = Settings.builder();
            builder.put("cluster.name", properties.getProperty("properties"));
            builder.put("client.transport.sniff", properties.getProperty("client.transport.sniff"));
            builder.put("xpack.security.user", properties.getProperty("xpack.security.user"));
            Settings settings = builder.build();
            if (settings.isEmpty()) {
                throw new Exception("ES设置项未设置.");
            }
            if (settings.get("xpack.security.user") == null || settings.get("xpack.security.user").equals("")) {
                ESUtil.client = new PreBuiltTransportClient(settings);
            } else {
                ESUtil.client = new PreBuiltXPackTransportClient(settings);
            }
            String transportAddress = properties.getProperty("transportAddress");
            if (transportAddress == null || transportAddress.equals("")) {
                throw new Exception("ES集群地址未设置.");
            }
            String[] address = transportAddress.split(",");
            for (int i = 0; i < address.length; i++) {
                String hoseName = address[i].split(":")[0];
                int port = Integer.parseInt(address[i].split(":")[1]);
                ESUtil.client.addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName(hoseName), port));
            }
            ESUtil.timeZone = properties.getProperty("default.timeZone", "Asia/Shanghai");
        }
        return ESUtil.client;
    }

}

3、API代码事例

3.1、查询

3.1.1、查询全部内容
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().get();
        SearchHits hits = searchResponse.getHits();
        System.out.println(hits.totalHits);
        if (hits.getTotalHits() > 0) {
            for (SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.1.2、设置索引
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().setIndices("file*").get();
        SearchHits hits = searchResponse.getHits();
        System.out.println(hits.totalHits);
        if (hits.getTotalHits() > 0) {
            for (SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.1.3、设置类型
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().setIndices("file*").setTypes("BIZZ").get();
        SearchHits hits = searchResponse.getHits();
        System.out.println(hits.totalHits);
        if (hits.getTotalHits() > 0) {
            for (SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.1.4、设置翻页
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().setFrom(0).setSize(100).get();
        SearchHits hits = searchResponse.getHits();
        System.out.println(hits.totalHits);
        if (hits.getTotalHits() > 0) {
            for (SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.1.5、字段过滤
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().setQuery(QueryBuilders.termQuery("level", "BIZZ")).get();
        SearchHits hits = searchResponse.getHits();
        System.out.println(hits.totalHits);
        if (hits.getTotalHits() > 0) {
            for (SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.1.6、通配符查询

  通配符支持 *? 两个, * 表示任意多个字符, ? 表示单个字符:

public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().setQuery(QueryBuilders.wildcardQuery("level", "I*")).get();
        SearchHits hits = searchResponse.getHits();
        System.out.println(hits.totalHits);
        if (hits.getTotalHits() > 0) {
            for (SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.1.7、多条件查询
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        ExistsQueryBuilder existsQueryBuilder = QueryBuilders.existsQuery("offset");
        TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("level", "BIZZ");
        BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery().must(existsQueryBuilder).must(termQueryBuilder);
        SearchResponse searchResponse = client.prepareSearch().setQuery(boolQueryBuilder).get();
        SearchHits hits = searchResponse.getHits();
        System.out.println(hits.totalHits);
        if (hits.getTotalHits() > 0) {
            for (SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.1.8、范围查询
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        ExistsQueryBuilder existsQueryBuilder = QueryBuilders.existsQuery("offset");
        RangeQueryBuilder rangeQueryBuilder = QueryBuilders.rangeQuery("offset").gte(0).lt(134166220);
        BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery().must(existsQueryBuilder).must(rangeQueryBuilder);
        SearchResponse searchResponse = client.prepareSearch().setQuery(boolQueryBuilder).get();
        SearchHits hits = searchResponse.getHits();
        System.out.println(hits.totalHits);
        if (hits.getTotalHits() > 0) {
            for (SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.1.9、时间查询

  对于时间范围查询,需要注意时区的问题。ES默认使用的UTC时区,在日起比较时需要设置为当前时区。还有一点需要注意:ES默认的时间格式是ISO8601。

public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().setQuery(QueryBuilders.rangeQuery("@timestamp").timeZone(ESUtil.getDefaultTimeZone()).gt("2017-07-25T16:30")).get();
        SearchHits hits = searchResponse.getHits();
        System.out.println(hits.totalHits);
        if (hits.getTotalHits() > 0) {
            for (SearchHit hit : hits) {
                System.out.println(hit.getSourceAsString());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

3.2、统计

3.2.1、简单分组统计
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().setQuery(QueryBuilders.existsQuery("level")).addAggregation(AggregationBuilders.terms("by_level").field("level")).get();
        StringTerms by_level = searchResponse.getAggregations().get("by_level");
        List<Terms.Bucket> buckets = by_level.getBuckets();
        for (Terms.Bucket bucket : buckets) {
            System.out.println(bucket.getKey() + ":" + bucket.getDocCount());
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.2.2、时间频度统计
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().setQuery(QueryBuilders.existsQuery("level")).addAggregation(AggregationBuilders.dateHistogram("by_day").field("@timestamp").dateHistogramInterval(DateHistogramInterval.DAY)).get();
        InternalDateHistogram by_day = searchResponse.getAggregations().get("by_day");
        List<InternalDateHistogram.Bucket> buckets = by_day.getBuckets();
        for (InternalDateHistogram.Bucket bucket : buckets) {
            DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
            df.setTimeZone(TimeZone.getTimeZone("Asia/shanghai"));
            System.out.println(new SimpleDateFormat("yyyy-MM-dd").format(df.parse(bucket.getKeyAsString())) + ":" + bucket.getDocCount());
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.2.3、多维度分组统计
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().setQuery(QueryBuilders.existsQuery("level")).addAggregation(
                AggregationBuilders.dateHistogram("by_day").field("@timestamp").dateHistogramInterval(DateHistogramInterval.DAY).subAggregation(
                        AggregationBuilders.terms("by_level").field("level")
                )
        ).get();
        InternalDateHistogram by_day = searchResponse.getAggregations().get("by_day");
        List<InternalDateHistogram.Bucket> buckets = by_day.getBuckets();
        for (InternalDateHistogram.Bucket bucket : buckets) {
            DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
            df.setTimeZone(TimeZone.getTimeZone("Asia/shanghai"));
            System.out.println(new SimpleDateFormat("yyyy-MM-dd").format(df.parse(bucket.getKeyAsString())) + ":" + bucket.getDocCount());
            InternalTerms by_level = bucket.getAggregations().get("by_level");
            List<Terms.Bucket> buckets_level = by_level.getBuckets();
            for (Terms.Bucket bucket_level : buckets_level) {
                System.out.println("\t" + bucket_level.getKey() + ":" + bucket_level.getDocCount());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
3.2.4、聚合函数
public static void main(String[] args) {
    try {
        TransportClient client = ESUtil.getClient();
        SearchResponse searchResponse = client.prepareSearch().setQuery(QueryBuilders.existsQuery("offset")).addAggregation(
                AggregationBuilders.dateHistogram("by_day").field("@timestamp").dateHistogramInterval(DateHistogramInterval.DAY).subAggregation(
                        AggregationBuilders.max("max_offset").field("offset")
                )
        ).get();
        InternalDateHistogram by_day = searchResponse.getAggregations().get("by_day");
        List<InternalDateHistogram.Bucket> buckets = by_day.getBuckets();
        for (InternalDateHistogram.Bucket bucket : buckets) {
            DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
            df.setTimeZone(TimeZone.getTimeZone("Asia/shanghai"));
            System.out.println(new SimpleDateFormat("yyyy-MM-dd").format(df.parse(bucket.getKeyAsString())) + ":" + bucket.getDocCount());
            InternalMax max_offset = bucket.getAggregations().get("max_offset");

            System.out.println("\t" + max_offset.getName() + ":" + max_offset.getValue());
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

4、注意事项

  • x-pack插件需要用到x-pack-transport依赖,x-pack并非开源(收费)软件,该依赖在Maven公共库中没有;
  • 日起过滤时注意时区设置;

5、参考资料:

6、补充:将任意Aggregations转换为JSON的例子

  以下代码算是一个思路,将多层嵌套的统计结果转换成json格式的字符串,调用方法类似这样:"{\"result\": [" + this.analysisAggregations(searchResponse.getAggregations()) + "]}";

private String analysisAggregations (Aggregations aggregations) {
    StringBuffer sb = new StringBuffer();
    for (Aggregation aggregation : aggregations.asList()) {
        if (aggregation instanceof StringTerms) {
            for (Terms.Bucket bucket : ((StringTerms) aggregation).getBuckets()) {
                String result = analysisAggregations(bucket.getAggregations());
                if (result == null || result.equals("")) {
                    result = String.valueOf(bucket.getDocCount());
                }
                if (result.indexOf(",") != -1) {
                    sb.append(",{\"").append(bucket.getKeyAsString()).append("\":[").append(result).append("]}");
                } else {
                    sb.append(",{\"").append(bucket.getKeyAsString()).append("\":").append(result).append("}");
                }
            }
        }
        if (aggregation instanceof InternalDateHistogram) {
            for (InternalDateHistogram.Bucket bucket : ((InternalDateHistogram) aggregation).getBuckets()) {
                String result = analysisAggregations(bucket.getAggregations());
                if (result == null || result.equals("")) {
                    result = String.valueOf(bucket.getDocCount());
                }
                if (result.indexOf(",") != -1) {
                    sb.append(",{\"").append(bucket.getKeyAsString()).append("\":[").append(result).append("]}");
                } else {
                    sb.append(",{\"").append(bucket.getKeyAsString()).append("\":").append(result).append("}");
                }
            }
        }
        if (aggregation instanceof InternalNumericMetricsAggregation.SingleValue) {
            sb.append(",{\"").append(aggregation.getName()).append("\":\"").append(((InternalNumericMetricsAggregation.SingleValue) aggregation).getValueAsString()).append("\"}");
        }
    }
    if (sb.length() == 0) {
        return "";
    }
    return sb.substring(1);
}
评论
成就一亿技术人!
拼手气红包6.0元
还能输入1000个字符
 
红包 添加红包
表情包 插入表情
 条评论被折叠 查看
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值