Es学习第十一课，使用java操作elasticsearch

前面十节课我们已经把ES的基本概念和使用讲的差不多了，现在我们就用基于java来实际开发一个操作ES的小项目，带大家来一起练练手。

1、我们用IDEA创建一个maven项目

项目结构如上图所示，然后我们就引入操作ES需要用到的jar和JUNIT,pom.xml最终配置如下：

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.kakatadage</groupId>
    <artifactId>esdemo</artifactId>
    <version>1.0-SNAPSHOT</version>

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.elasticsearch.client</groupId>
        <artifactId>transport</artifactId>
        <version>6.5.1</version>
    </dependency>

</dependencies>

    <build>
    <finalName>esdemo</finalName>
    <plugins>
    <plugin>
        <!-- 设置javac编译器的版本和编码字符 -->
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
            <source>1.8</source>
            <target>1.8</target>
            <encoding>utf8</encoding><!-- 编译器编码 -->
        </configuration>
    </plugin>
    </plugins>
    </build>
</project>

项目创建完成后，我们就可以针对ES实现数据的增删改查了。

2、实现ES实现查询

新建一个测试类，如下图：

最后代码如下所示：

package com.kakatadage.esdemo.test;

import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.Test;

import java.net.InetAddress;
import java.net.UnknownHostException;

public class EsDemo {

    //从ES中查询数据
    @Test
    public void test1() throws UnknownHostException {
        //指定ES集群
        Settings setting = Settings.builder().put("cluster.name",
                "my-application").build();

        //创建访问ES服务器的客户端
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                                 .addTransportAddress(
                                         new TransportAddress(
                                                 InetAddress.getByName("127.0.0.1"),9300));
        //get方式数据查询 ,参数为Index,type和id
        GetResponse response = client.prepareGet("lib4","items","5").get();

        System.out.println(response.getSourceAsString());
        client.close();
    }
}

返回结果就是一个JSON字符串

{ "price" : null, "itemID" : "ID1005" }

3、java 插入ES一条数据

   //插入数据
    @Test
    public void test2() throws IOException {
        //指定ES集群
        Settings setting = Settings.builder().put("cluster.name",
                "my-application").build();

        //创建访问ES服务器的客户端
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(
                        new TransportAddress(
                                InetAddress.getByName("127.0.0.1"),9300));

        XContentBuilder doc = XContentFactory.jsonBuilder()
                .startObject()
                .field("id","1")
                .field("title","我在学习es插入操作")
                .field("content","好好学习，天天向上")
                .endObject();

        //添加一个doc
        IndexResponse response = client.prepareIndex("lib5","testadd",null)//id为null，由ES自己生成
                .setSource(doc).get();
        System.out.println(response.status());//打印添加是否成功
        client.close();
    }

返回结果：

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 1,
    "max_score": 1,
    "hits": [
      {
        "_index": "lib5",
        "_type": "testadd",
        "_id": "dympT2cBfvwZhJjhaFQ3",
        "_score": 1,
        "_source": {
          "id": "1",
          "title": "我在学习es插入操作",
          "content": "好好学习，天天向上"
        }
      }
    ]
  }
}

4、java 删除ES一个文档

    //删除文档
    @Test
    public void test3() throws IOException {
        //指定ES集群
        Settings setting = Settings.builder().put("cluster.name",
                "my-application").build();

        //创建访问ES服务器的客户端
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(
                        new TransportAddress(
                                InetAddress.getByName("127.0.0.1"),9300));

        DeleteResponse response = client.prepareDelete("lib5","testadd","dympT2cBfvwZhJjhaFQ3")
                .get();
        System.out.println(response.status());//打印添加是否成功
        client.close();
    }

5、java 修改ES一个文档

我们先新增一个，然后根据它的ID来更新

    //更新文档
    @Test
    public void test4() throws IOException, ExecutionException, InterruptedException {
        //指定ES集群
        Settings setting = Settings.builder().put("cluster.name",
                "my-application").build();

        //创建访问ES服务器的客户端
        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(
                        new TransportAddress(
                                InetAddress.getByName("127.0.0.1"),9300));
        UpdateRequest request = new UpdateRequest();
        request.index("lib5")
                .type("testadd")
                .id("eCm1T2cBfvwZhJjhF1SM")
                .doc(
                        XContentFactory.jsonBuilder().startObject()
                        .field("title","我在学习ES的修改操作")
                                .field("newadd","新增字段")
                        .endObject()
                );
        UpdateResponse response = client.update(request).get();

        System.out.println(response.status());//打印是否成功
        client.close();
    }