Java客户端操作elasticsearch集群（maven）

刚学习了使用Java客户端来操作本地elasticsearch，这里记录一下使用方法！
开发工具：IntelliJ IDEA 2019.3
在使用Java客户端操作之前，要在本地先配置集群哦！下面是配置方法
window10下elasticsearch创建集群方法（本地）

一、创建空项目

先在idea上创建一个基于maven的空项目，使用maven来引入相关jar包

二、导入jar包

在pom.xml文件里面导入相关jar包，如果想要导入其他版本的，到mvnrepository里面找就可以了

	<dependencies>
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.6.2</version>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>transport</artifactId>
            <version>7.6.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-to-slf4j</artifactId>
            <version>2.13.1</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.30</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.21</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.8</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.8</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.9.8</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-elasticsearch</artifactId>
            <version>3.2.6.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.1.5.RELEASE</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.plugin</groupId>
            <artifactId>transport-netty4-client</artifactId>
            <version>7.1.1</version>
        </dependency>
    </dependencies>

导入包后，如果运行时出现错误提示是jar包有冲突的，可以去插件plugins里面下载maven helper 插件，在pom.xml里面查看哪些冲突了，具体方法看这位大佬的解决方法：idea中解决jar包冲突方法

三、操作及相关代码：

在src/main/java下新建package，命名随意，这里为 com.es，然后建Java文件
这里要先封装一个article，下面会用到

package com.es.entity;

public class Article {
    
    
	//文章ID
    private long id;
	//文章标题
    private String title;
	//文章内容
    private String content;
	//getter和setter方法
    public long getId() {
    
    
        return id;
    }

    public void setId(long id) {
    
    
        this.id = id;
    }

    public String getTitle() {
    
    
        return title;
    }

    public void setTitle(String title) {
    
    
        this.title = title;
    }

    public String getContent() {
    
    
        return content;
    }

    public void setContent(String content) {
    
    
        this.content = content;
    }
}

1、相关创建方法

import com.es.entity.Article;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.Before;
import org.junit.Test;
import java.net.InetAddress;

public class ESClientTest {
    
    

    private TransportClient client;

    @Before
    public void init() throws Exception{
    
    
        //创建settings对象，配置集群名称
        //注意这里集群名称要跟自己本地配置的名称一致
        Settings settings = Settings.builder().put("cluster.name","my-es").build();
        //创建客户端对象，端口号也是上面配置本地集群的端口号
        client = new PreBuiltTransportClient(settings);
        client.addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"),9301));
        client.addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"),9302));
        client.addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"),9303));
    }

    /**
     * 创建索引方法
     * @throws Exception
     */
    @Test
    public void createIndex() throws Exception{
    
    
        //使用client创建一个索引库,并执行操作
        client.admin().indices().prepareCreate("index").get();
        //关闭client
        client.close();
    }

    /**
     * 创建文档方法1
     * @throws Exception
     */
    @Test
    public void addDocument1() throws Exception{
    
    
       //创建一个文档对象，这里是
        XContentBuilder builder = XContentFactory.jsonBuilder()
                .startObject()
                    .field("id",1)
                    .field("title","this is a title")
                    .field("content","this is content!")
                .endObject();
        //把文档对象添加到索引库
        client.prepareIndex()
                .setIndex("index")   		//设置索引名称
                .setType("article")         //设置type
                .setId("1")                 //设置文档id，如果不设置自动生成
                .setSource(builder)         //设置文档信息
                .get();                     //执行操作
        //关闭client客户端
        client.close();
    }

    /**
     * 创建文档方法2
     * 由于方法1过于麻烦，所以一般用方法2这种形式
     * @throws Exception
     */
    @Test
    public void addDocument2() throws Exception{
    
    
        //创建article对象
        Article article = new Article();
        //设置对象属性
        article.setId(2);
        article.setTitle("this is a title");
        article.setContent("there are some things");
        //把article对象装换成json格式对象
        ObjectMapper objectMapper = new ObjectMapper();
        String jsonDocument = objectMapper.writeValueAsString(article);
        System.out.println(jsonDocument);
        //使用client对象把文档写入索引库
        client.prepareIndex("index","article","2")
                .setSource(jsonDocument, XContentType.JSON)
                .get();
        //关闭client
        client.close();
    }

    /**
     * 创建多个文档，为搜索提供数据
     * @throws Exception
     */
    @Test
    public void addDocument3() throws Exception{
    
    
        for (int i = 3; i<20 ;i++) {
    
    
            //创建article对象
            Article article = new Article();
            //设置对象属性
            article.setId(i);
            article.setTitle("this is a title"+i);
            article.setContent("you worth it"+i);
            //把article对象装换成接送格式对象
            ObjectMapper objectMapper = new ObjectMapper();
            String jsonDocument = objectMapper.writeValueAsString(article);
            System.out.println(jsonDocument);
            //使用client对象把文档写入索引库
            client.prepareIndex("index", "article", i+"")
                    .setSource(jsonDocument, XContentType.JSON)
                    .get();
        }
        //关闭client
        client.close();
    }
}

由于创建client客户端是每个方法都必须完成的工作，为了减少代码冗余，就把他提取到@Before里面，@Before注解的功能就是无论执行哪个Test，都会先运行@Before下面的方法再运行Test注解下的方法，所以很好的解决了代码冗余

2、查询方法

import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.text.Text;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.index.query.QueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightField;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.Before;
import org.junit.Test;

import java.net.InetAddress;
import java.util.Iterator;
import java.util.Map;

public class searchIndexTest {
    
    
    private TransportClient client;

    @Before
    public void init() throws Exception{
    
    
        //创建settings对象，配置集群名称
        Settings settings = Settings.builder().put("cluster.name","my-es").build();
        //创建客户端对象
        client = new PreBuiltTransportClient(settings);
        client.addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"),9301));
        client.addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"),9302));
        client.addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"),9303));
    }

    private void search(QueryBuilder queryBuilder) throws Exception{
    
    
        //执行查询
        SearchResponse searchResponse = client.prepareSearch("index")
                .setTypes("article")
                .setQuery(queryBuilder)
                .get();
        //取查询结果
        SearchHits searchHits = searchResponse.getHits();
        //取查询结果总记录数
        System.out.println("查询结果总记录数"+searchHits.getTotalHits());
        //查询结果列表
        Iterator<SearchHit> iterator = searchHits.iterator();
        while (iterator.hasNext()){
    
    
            SearchHit searchHit = iterator.next();
            //以json格式输出
            System.out.println(searchHit.getSourceAsString());
        }
        //关闭client
        client.close();
    }

    /**
     * ID查询步骤：
     * 1.创建一个client对象
     * 2.创建查询对象
     * 3.使用client执行查询
     * 4.得到查询结果
     * 5.取查询结果总记录数
     * 6.取查询结果列表
     * 7.关闭client
     */
    @Test
    public void searchById() throws Exception{
    
    
        //创建一个client对象
        //创建查询对象
        QueryBuilder queryBuilder = QueryBuilders.idsQuery().addIds("1","2");
        search(queryBuilder);
    }

    /**
     * 字段查询
     * @throws Exception
     */
    @Test
    public void searchByTerm() throws Exception{
    
    
        QueryBuilder queryBuilder = QueryBuilders.termQuery("title","is");
        search(queryBuilder);
    }

    /**
     * string查询
     * @throws Exception
     */
    @Test
    public void queryString() throws Exception{
    
    
        QueryBuilder queryBuilder = QueryBuilders.queryStringQuery("is")
                .defaultField("content");
        search(queryBuilder);
    }

    /**
     * 分页查询
     * @throws Exception
     */
    @Test
    public void pageQuery() throws Exception{
    
    
        QueryBuilder queryBuilder = QueryBuilders.queryStringQuery("this")
                .defaultField("title");
        //执行查询
        SearchResponse searchResponse = client.prepareSearch("index")
                .setTypes("article")
                .setQuery(queryBuilder)
                //设置分页信息
                .setFrom(0)     //起始位置
                .setSize(5)     //每页显示数量
                .get();
        //取查询结果
        SearchHits searchHits = searchResponse.getHits();
        //取查询结果总记录数
        System.out.println("查询结果总记录数"+searchHits.getTotalHits());
        //查询结果列表
        Iterator<SearchHit> iterator = searchHits.iterator();
        while (iterator.hasNext()){
    
    
            SearchHit searchHit = iterator.next();
            //以json格式输出
            System.out.println(searchHit.getSourceAsString());
        }
        //关闭client
        client.close();
    }

    /**
     * 查询字段高亮显示
     * @throws Exception
     */
    @Test
    public void highView() throws Exception{
    
    
        String highlightField = "title";
        HighlightBuilder highlightBuilder = new HighlightBuilder();
        highlightBuilder.field(highlightField);
        highlightBuilder.preTags("<em>");	//这里相当于前端添加标签<em>
        highlightBuilder.postTags("</em>");	
        QueryBuilder queryBuilder = QueryBuilders.queryStringQuery("this")
                .defaultField("title");
        //执行查询
        SearchResponse searchResponse = client.prepareSearch("index_hello")
                .setTypes("article")
                .setQuery(queryBuilder)
                //设置分页信息
                .setFrom(0)     //起始位置
                .setSize(5)     //每页显示行数
                //设置高亮显示
                .highlighter(highlightBuilder)
                .get();
        //取查询结果
        SearchHits searchHits = searchResponse.getHits();
        //取查询结果总记录数
        System.out.println("查询结果总记录数"+searchHits.getTotalHits());
        //查询结果列表
        Iterator<SearchHit> iterator = searchHits.iterator();
        while (iterator.hasNext()){
    
    
            SearchHit searchHit = iterator.next();
            //以json格式输出
            System.out.println(searchHit.getSourceAsString());
            //高亮输出
            System.out.println("--------高亮输出--------");
            Map<String, HighlightField> highlight = searchHit.getHighlightFields();
            System.out.println(highlight);
            //取高亮显示的结果
            System.out.println("--------高亮显示结果输出--------");
            HighlightField field = highlight.get(highlightField);
            Text[] fragments = field.getFragments();
            if (fragments != null){
    
    
                String title = fragments[0].toString();
                System.out.println(title);
            }
        }
        //关闭client
        client.close();
    }
}

由于执行查询的代码都是一样的，所以避免冗余，提取相同的代码放入search方法中

我是在B站学的，有什么不懂的可以去B站看看视频，比较容易理解（下面贴上地址）

传智黑马Elasticsearch教学视频

【狂神说Java】ElasticSearch7.6.x最新完整教程通俗易懂

Tip：代码来源是第一个视频，个人觉得可以直接看第二个