使用elasticsearch建立搜索引擎

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使用elasticsearch建立搜索引擎

elasticsearch官方网址：https://www.elastic.co/products/elasticsearch

1、选择Elasticsearch的原因

（1）Elasticsearch是一个建立在全文搜索引擎 Apache Lucene™ 基础上的开源的实时分布式搜索和分析引擎，功能强大：

• 支持全文搜索；
• 分布式实时文件存储，并将每一个字段都编入索引，使其可以被搜索；
• 实时分析的分布式搜索引擎；
• 可以扩展到上百台服务器，处理PB级别的结构化或非结构化数据。

所有的这些功能被集成到一个服务里面，你的应用可以通过简单的RESTful API、各种语言的客户端甚至命令行与之交互。

（2）简单易学，文档齐全

搜索引擎选择： Elasticsearch与Solr：http://www.cnblogs.com/chowmin/articles/4629220.html

2、安装并配置Elasticsearch

因为我们要使用ansj分词工具进行分词，最新的ansj与elasticsearch结合的工具包对应的elastic search的版本是5.0.1，所以我们下载5.0.1版本的elasticsearch。

（1）下载并解压

wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-5.0.1.tar.gz
sha1sum elasticsearch-5.0.1.tar.gz
tar -xzf elasticsearch-5.0.1.tar.gz
cd elasticsearch-5.0.1/ 

（2）启动ES

./bin/elasticsearch

16-12-11T17:28:33,912][INFO ][o.e.n.Node ] [rpA7Jx3] started

看到类似这一句的，则说明启动ES了

新开一个终端，查看是否运行成功

curl -XGET 'localhost:9200/?pretty'

出现如上形式内容，则说明ES运行成功。

可以按Ctrl-C关闭ES

3、安装并配置ansj分词器

进入es目录执行如下命令

./bin/elasticsearch-plugin install http://maven.nlpcn.org/org/ansj/elasticsearch-analysis-ansj/5.0.1.0/elasticsearch-analysis-ansj-5.0.1.0-release.zip

4、elasticsearch启动出现的错误解决

（1）Java HotSpot™ 64-Bit Server VM warning: INFO:
os::commit_memory(0x0000000085330000, 2060255232, 0) failed; error=‘Cannot allocate memory’ (errno=12)

由于elasticsearch5.0默认分配jvm空间大小为2g，修改jvm空间分配

# vim config/jvm.options  
-Xms2g  
-Xmx2g  

修改为

-Xms512m  
-Xmx512m  

（2）max number of threads [1024] for user [elasticsearch] is too low, increase to at least [2048]

修改 /etc/security/limits.d/90-nproc.conf

原： soft nproc 1024
改为： soft nproc 2048

（3）max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]

修改/etc/sysctl.conf配置文件，

cat /etc/sysctl.conf | grep vm.max_map_count
vm.max_map_count=262144

如果不存在则添加

echo "vm.max_map_count=262144" >>/etc/sysctl.conf

（4）max file descriptors [65535] for elasticsearch process likely too low, increase to at least [65536]

ulimit -n 65536

（5）[root@localhost elasticsearch-5.0.1]# ./bin/elasticsearch
[WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [] uncaught exception in thread [main]
org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root

注意：ES不能用root管理员身份启动

5、配置elasticsearch Java API

在pom.xml添加如下依赖：

<!-- elasticsearch Java API -->
<dependency>
	<groupId>org.elasticsearch.client</groupId>
	<artifactId>transport</artifactId>
	<version>5.0.1</version>
</dependency>
<dependency>
	<groupId>org.apache.logging.log4j</groupId>
	<artifactId>log4j-api</artifactId>
	<version>2.8.0</version>
</dependency>
<dependency>
	<groupId>org.apache.logging.log4j</groupId>
	<artifactId>log4j-core</artifactId>
	<version>2.8.0</version>
</dependency>

6、elasticsearch教程

• 官方教程：https://www.elastic.co/guide/en/elasticsearch/reference/current/zip-targz.html
• Elasticsearch基础教程：http://blog.csdn.net/cnweike/article/details/33736429
• Elasticsearch JAVA API教程：http://www.07net01.com/2016/07/1603264.html

1. Java API批量导出

 Settings settings = ImmutableSettings.settingsBuilder().put("cluster.name", "elasticsearch-bigdata").build();
Client client = new TransportClient(settings)
        .addTransportAddress(new InetSocketTransportAddress("10.58.71.6", 9300));
SearchResponse response = client.prepareSearch("bigdata").setTypes("student")
       .setQuery(QueryBuilders.matchAllQuery()).setSize(10000).setScroll(new TimeValue(6000                  00))
        .setSearchType(SearchType.SCAN).execute().actionGet();//setSearchType(SearchType.Scan) 告诉ES不需要排序只要结果返回即可 setScroll(new TimeValue(600000)) 设置滚动的时间
String scrollid = response.getScrollId();
try {
//把导出的结果以JSON的格式写到文件里
    BufferedWriter out = new BufferedWriter(new FileWriter("es", true));
    
    //每次返回数据10000条。一直循环查询直到所有的数据都查询出来
    while (true) {
        SearchResponse response2 = client.prepareSearchScroll(scrollid).setScroll(new TimeValue(1000000))
                .execute().actionGet();
        SearchHits searchHit = response2.getHits();
        //再次查询不到数据时跳出循环
        if (searchHit.getHits().length == 0) {
            break;
        }
        System.out.println("查询数量 ：" + searchHit.getHits().length);
        for (int i = 0; i < searchHit.getHits().length; i++) {
            String json = searchHit.getHits()[i].getSourceAsString();
            out.write(json);
            out.write("\r\n");
        }
    }
    System.out.println("查询结束");
    out.close();
} catch (FileNotFoundException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

2. Java API 批量导入

Settings settings = ImmutableSettings.settingsBuilder().put("cluster.name", "elasticsearch-bigdata").build();
Client client = new TransportClient(settings)
        .addTransportAddress(new InetSocketTransportAddress("10.58.71.6", 9300));
try {
//读取刚才导出的ES数据
    BufferedReader br = new BufferedReader(new FileReader("es"));
    String json = null;
    int count = 0;
    //开启批量插入
    BulkRequestBuilder bulkRequest = client.prepareBulk();
    while ((json = br.readLine()) != null) {
        bulkRequest.add(client.prepareIndex("bigdata", "student").setSource(json));
        //每一千条提交一次
        if (count% 1000==0) {
            bulkRequest.execute().actionGet();
            System.out.println("提交了：" + count);
        }
        count++;
    }
    bulkRequest.execute().actionGet();
    System.out.println("插入完毕");
    br.close();
} catch (FileNotFoundException e) {
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

elasticsearch导入数据的两种方法

第一种方法：手动导入

1、cat test.json

{"index":{"_index":"stuff_orders","_type":"order_list","_id":903713}}
{"real_name":"刘备","user_id":48430,"address_province":"上海","address_city":"浦东新区","address_district":null,"address_street":"上海市浦东新区广兰路1弄2号345室","price":30.0,"carriage":6.0,"state":"canceled","created_at":"2013-10-24T09:09:28.000Z","payed_at":null,"goods":["营养早餐：火腿麦满分"],"position":[121.53,31.22],"weight":70.0,"height":172.0,"sex_type":"female","birthday":"1988-01-01"}

2、导入elasticsearch

[root@ELKServer opt]# curl -XPOST ‘localhost:9200/stuff_orders/_bulk?pretty‘ --data-binary @test.json
{
  "took" : 600,
  "errors" : false,
  "items" : [ {
    "index" : {
      "_index" : "stuff_orders",
      "_type" : "order_list",
      "_id" : "903713",
      "_version" : 1,
      "_shards" : {
        "total" : 2,
        "successful" : 1,
        "failed" : 0
      },
      "status" : 201
    }
  } ]
}

3、查看elasticsearch是否存在数据

[root@ELKServer opt]# curl localhost:9200/stuff_orders/order_list/903713?pretty
{
  "_index" : "stuff_orders",
  "_type" : "order_list",
  "_id" : "903713",
  "_version" : 1,
  "found" : true,
  "_source" : {
    "real_name" : "刘备",
    "user_id" : 48430,
    "address_province" : "上海",
    "address_city" : "浦东新区",
    "address_district" : null,
    "address_street" : "上海市浦东新区广兰路1弄2号345室",
    "price" : 30.0,
    "carriage" : 6.0,
    "state" : "canceled",
    "created_at" : "2013-10-24T09:09:28.000Z",
    "payed_at" : null,
    "goods" : [ "营养早餐：火腿麦满分" ],
    "position" : [ 121.53, 31.22 ],
    "weight" : 70.0,
    "height" : 172.0,
    "sex_type" : "female",
    "birthday" : "1988-01-01"
  }
}

第二种方法：从数据库中导入

1、下载安装插件elasticsearch-jdbc-2.3.4.0

wget http://xbib.org/repository/org/xbib/elasticsearch/importer/elasticsearch-jdbc/2.3.4.0/elasticsearch-jdbc-2.3.4.0-dist.zip
# elasticsearch-jdbc-2.3.4.0-dist.zip的版本要和你安装的elasticsearch对应。 
unzip elasticsearch-jdbc-2.3.4.0-dist.zip
mv elasticsearch-jdbc-2.3.4.0 /usr/local/
cd /usr/local/elasticsearch-jdbc-2.3.4.0/

2、配置脚本

vim import.sh
#!/bin/sh
JDBC_IMPORTER_HOME=/usr/local/elasticsearch-jdbc-2.3.4.0
bin=$JDBC_IMPORTER_HOME/bin
lib=$JDBC_IMPORTER_HOME/lib
echo ‘{
"type" : "jdbc",
"jdbc": {
"elasticsearch.autodiscover":true,
"elasticsearch.cluster":"my-application", #簇名 详见：/usr/local/elasticsearch/config/elasticsearch.yml
"url":"jdbc:mysql://localhost:3306/test",  #mysql数据库地址
"user":"test",  #mysql用户名
"password":"1234",  #mysql密码
"sql":"select *,id as _id from workers_info",
"elasticsearch" : {
  "host" : "192.168.10.49",
  "port" : 9300
},
"index" : "myindex",  #新的index
"type" : "mytype"  #新的type
}
}‘| java   -cp "${lib}/*"   -Dlog4j.configurationFile=${bin}/log4j2.xml   org.xbib.tools.Runner   org.xbib.tools.JDBCImporter
chmod + import.sh
sh import.sh

3、查看数据是否导入elasticsearch

[root@ELKServer bin]# curl -XGET ‘http://localhost:9200/myindex/mytype/_search?pretty‘
{
  "took" : 15,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "failed" : 0
  },
  "hits" : {
    "total" : 1,
    "max_score" : 1.0,
    "hits" : [ {
      "_index" : "myindex",
      "_type" : "mytype",
      "_id" : "AVZyXCReGHjmX33dpJi3",
      "_score" : 1.0,
      "_source" : {
        "id" : 1,
        "workername" : "xing",
        "salary" : 10000,
        "tel" : "1598232123",
        "mailbox" : "[email protected]",
        "department" : "yanfa",
        "sex" : "F",
        "qq" : 736019646,
        "EmployedDates" : "2012-12-21T00:00:00.000+08:00"
      }
    } ]
  }
}

实战代码

古诗文搜索引擎实战github地址：https://github.com/AngelaFighting/gushiwensearch

1、启动ES

Windows系统，在ES目录的bin目录中打开命令行窗口，输入命令：·elasticsearch.bat·，回车，如果看到ES集群显示started并且状态为Green，则说明启动成功

2、使用浏览器打开首页

输入要查询的内容，并选择搜索范围，点击搜索按钮

可看到匹配的结果数和各个结果的部分信息。

点击某篇诗文的链接，就可以查看诗文的详细信息了。