ElasticSearch 增删改查

0 概述

本文主要介绍使用java API 对ElasticSearch 的增删改查的操作，以及在增删改查中遇到的问题。
项目依赖pom

<dependencies>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>transport</artifactId>
            <version>5.0.0</version>
        </dependency>
        <!--log4j2 这个是强依赖-->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.6.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.6.2</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.29</version>
        </dependency>
    </dependencies>

1 数据写入

数据写入前建议提前创建好索引和mapping，因为提前创建好可以确定该字段的类型和是否需要分词，否则的话ElasticSearch 会自动根据插入的数据自动创建mapping。创建的方法具体可以见：创建索引和mapping

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.action.support.WriteRequest;
import org.elasticsearch.rest.RestStatus;

import java.util.Map;

/**
 * Created by hsc on 17/4/29.
 */
public class ElasticSearchOperations {

    private static final Logger logger = LogManager.getLogger(ElasticSearchOperations.class);

    /**
     * @param index   索引 名称
     * @param type    文档类型
     * @param id      文档id(相当于关系数据库表的主键)
     * @param dataMap 数据
     * @return
     */
    public static boolean AddOrUpdate(String index, String type, String id, Map<String, Object> dataMap) {
        try {
            IndexResponse indexRespons = ESClient.getInstance()
                    .prepareIndex(index, type)
                    .setId(id)
                    .setSource(dataMap)
                    .get();
            return isSuccess(indexRespons);
        } catch (Exception ex) {
            logger.error("save or update elasticsearch exception", ex);
        }
        return false;
    }

    private static boolean isSuccess(Object response) {
        if (response instanceof IndexResponse) {
            //返回状态有两种情况-第一:该文档id不存在,进行创建写入RestStatus.CREATED ; 第二,文档id已经存在,进行更新操作返回RestStatus.OK
            return RestStatus.CREATED.equals(((IndexResponse) response).status()) || RestStatus.OK.equals(((IndexResponse) response).status());
        } else if (response instanceof DeleteResponse) {
            return RestStatus.OK.equals(((DeleteResponse) response).status());
        }
        return false;
    }

    public static boolean delete(String index, String type, String id) {
        try {
            DeleteResponse deleteResponse = ESClient.getInstance().prepareDelete(index, type, id).get();
            return isSuccess(deleteResponse);
        } catch (Exception ex) {
            logger.error("delete elasticSearch exception", ex);
        }
        return false;

    }


}

值得强调的是：在数据写入时候，如果不指定文档Id，ES 会自动创建id，相当于关系数据库中自增的主键id。如果插入数据时候该文档Id已经存在，ES则会更新这条记录
Elasticsearch操作数据后马上更新的办法，就是写入数据时候刷新下，具体的写法可以见下面

   IndexResponse indexRespons = ESClient.getInstance()
                    .prepareIndex(index, type)
                    .setId(id)
                    .setSource(dataMap)
                    .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
                    .get();

2数据查询

这里只是给出一个简单的查询方式

import org.elasticsearch.action.search.SearchRequestBuilder;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.search.SearchHits;

/**
 * Created by hsc on 17/4/29.
 */
public class SearchComponent {
    public static SearchHits search(String index, String type) {
        try {
            SearchResponse searchResponse = buildSearchRequestBuilder(index, type, 100).execute().get();
            return searchResponse.getHits();
        } catch (Exception ex) {
            System.out.print("search exception " + ex.getMessage());
        }
        return null;
    }

    private static SearchRequestBuilder  buildSearchRequestBuilder(String index, String type, int size) {
        SearchRequestBuilder searchRequestBuilder = ESClient.getInstance().prepareSearch();
        searchRequestBuilder.setIndices(index)
                .setTypes(type)
                .setSize(size);
        return searchRequestBuilder;
    }
}

测试主类

import com.alibaba.fastjson.JSON;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;

import java.util.HashMap;
import java.util.Map;

/**
 * Created by hsc on 17/4/29.
 */
public class Test {
    public static void main(String[] args) {
        String index = "index";
        String type = "test";
        Map<String, Object> data = new HashMap<String, Object>();
        data.put("userId", 1213);
        data.put("userName", "hsc");
        ElasticSearchOperations.AddOrUpdate(index, type, "test2", data);
        SearchHits searchHits = SearchComponent.search(index, type);
        if (searchHits != null) {
            System.out.println("总共数据:"+searchHits.getTotalHits());
            for (SearchHit hit : searchHits.getHits()) {
                System.out.println(JSON.toJSON(hit.getSource()));
            }
        }
    }
}