eclasticsearch文档搜索

版本选择，参考：https://blog.csdn.net/2301_79098963/article/details/138275506

下载elasticsearch-7-10-0，选择windows版本，zip包解压到指定目录即可

https://www.elastic.co/downloads/past-releases/elasticsearch-7-10-0

对于word、pdf等文档类型的文件而言，它们文件底层的内容除了纯文本之外，还会有很多杂乱的信息（比如在一个word文件中，除了文本内容，还包含了页面设置、字体大小、颜色等无关信息）

为了剔除文档中与文本无关的信息，所以才需要使用文本抽取插件

安装文本抽取插件：ingest-attachment

windows下命令（进到bin目录）：

elasticsearch-plugin install ingest-attachment

Linux下命令（进到bin目录）：

./elasticsearch-plugin install ingest-attachment

安装完成后，可以看到：

为了方便后续检索文本，需要安装一个IK分词器插件（官方下载地址：https://github.com/medcl/elasticsearch-analysis-ik

官方里面也有说明如何进行下载。选择一个和你elasticsearch版本相同的版本进行下载即可，此时可能需要用到翻墙软件。比如执行以下命令：

windows下（进到bin目录）：

elasticsearch-plugin install https://release.infinilabs.com/analysis-ik/stable/elasticsearch-analysis-ik-7.10.0.zip

elasticsearch启动：

K:\elasticsearch-7.10.0\bin>elasticsearch

回车即可

springboot集成elasticsearch

1、在yml中添加es的配置

...

#elasticsearch info

es:

elasticsearch:

url: 127.0.0.1

port: 9200

2、maven中引入相关jar

复制代码

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
    </dependency>

3、创建客户端，目前一般创建HigeLevelClient。这个根据es的版本而定。

import org.apache.http.HttpHost;

import org.elasticsearch.client.RestClient;

import org.elasticsearch.client.RestHighLevelClient;

import org.springframework.beans.factory.annotation.Value;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

@Configuration

public class ElasticsearchConfig {

@Value("${es.elasticsearch.url}")

private String esHost;

复制代码

@Value("${es.elasticsearch.port}")
private int esPort;

@Bean
public RestHighLevelClient restHighLevelClient() {
    // 设置连接的用户名密码
    return new RestHighLevelClient(RestClient.builder(new HttpHost(esHost, esPort, "http")));
}

}

4、访问es

package cn.fss.elasticsearch;

import java.util.Arrays;

import org.elasticsearch.action.DocWriteResponse;

import org.elasticsearch.action.delete.DeleteRequest;

import org.elasticsearch.action.delete.DeleteResponse;

import org.elasticsearch.action.index.IndexRequest;

import org.elasticsearch.action.index.IndexResponse;

import org.elasticsearch.action.search.SearchRequest;

import org.elasticsearch.action.search.SearchResponse;

import org.elasticsearch.client.RequestOptions;

import org.elasticsearch.client.RestHighLevelClient;

import org.elasticsearch.common.unit.TimeValue;

import org.elasticsearch.common.xcontent.XContentType;

import org.elasticsearch.search.builder.SearchSourceBuilder;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Component;

import com.alibaba.fastjson2.JSON;

import cn.fss.common.core.page.TableDataInfo;

import lombok.extern.slf4j.Slf4j;

@Component

@Slf4j

public class ElasticSearchClient {

复制代码

@Autowired

private RestHighLevelClient restHighLevelClient;

/**
 * 获得关键词搜索结果
 * @param index
 * @param sourceBuilder
 * @return
 */
public TableDataInfo selectDocumentList(String index, SearchSourceBuilder sourceBuilder) {
    try {
        SearchRequest request = new SearchRequest(index);
        if (sourceBuilder != null) {
            // 返回实际命中数
            sourceBuilder.trackTotalHits(true);
            request.source(sourceBuilder);
        }
        SearchResponse response = restHighLevelClient.search(request, RequestOptions.DEFAULT);
        if (response.getHits() != null) {
            System.out.println("total========="+response.getHits().getTotalHits().value);
            TableDataInfo data = new TableDataInfo();
            data.setRows(Arrays.asList(response.getHits().getHits()));
            data.setTotal(response.getHits().getTotalHits().value);//命中总数
            return data;
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

/**
 * 插入/修改文档信息
 * @param index 索引
 * @param data  数据
 * @param docId
 */
public Boolean insertDocument(String index, String docId, Object data) {
    try {
        IndexRequest request = new IndexRequest(index);
        request.timeout(TimeValue.timeValueSeconds(10));//10秒
        request.id(docId);//如果先前已经上传过文件，此时再次插入会更新。
        // 重要！！必须设置管道
        request.setPipeline("attachment");//文件通道
        request.source(JSON.toJSONString(data), XContentType.JSON);
        IndexResponse response = restHighLevelClient.index(request, RequestOptions.DEFAULT);
        log.info("[es] 插入文档的响应状态: status:{},id:{}", response.status().getStatus(), response.getId());
        String status = response.status().toString();
        if ("CREATED".equals(status) || "OK".equals(status)) {
            log.debug("[es] 插入或修改文档成功! ");
            return true;
        }
    } catch (Exception e) {
        log.error("[es] 插入或修改文档失败",e);
    }
    return false;
}

/**
 * 删除某个index的docId
 * @param index
 * @param docId
 * @return
 */
public boolean deleteDocument(String index,String docId) {
    try {
        DeleteRequest request = new DeleteRequest(index,docId);
        DeleteResponse res = restHighLevelClient.delete(request, RequestOptions.DEFAULT);
        log.info("index:[{}],docId:[{}],进行删除操作，es返回的结果是："+res.getResult());
        if(res.getResult() == DocWriteResponse.Result.DELETED) {
            return true;
        }
        
    }catch(Exception ex) {
        log.error(ex.getMessage(),ex);
    }
    return false;
}

}

如果存储的是word、pdf或txt文本格式，需要以下几个步骤

1、在es中创建文件通道，put方式，注意attachment，这个在java代码中会用到

http://localhost:9200/_ingest/pipeline/attachment

2、创建索引，put方式，docwrite就是索引名称，代码中也会用到

http://localhost:9200/docwrite

3、word、txt或pdf文件，需要转成base64

import java.uitl.Base64;

...

private String getFileBase64(File file) {

Base64.Encoder base64 = Base64.getEncoder();

String base64Str = null;

try (FileInputStream fis = new FileInputStream(file);

ByteArrayOutputStream bos = new ByteArrayOutputStream()) {

byte[] b = new byte[1024];

int n;

while ((n = fis.read(b)) != -1) {

bos.write(b, 0, n);

}

base64Str = base64.encodeToString(bos.toByteArray());

} catch (Exception e) {

e.printStackTrace();

}

return base64Str;

复制代码

4、service层代码

package cn.fss.elasticsearch.service.impl;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import org.apache.commons.lang3.StringUtils;

import org.elasticsearch.common.text.Text;

import org.elasticsearch.index.query.QueryBuilders;

import org.elasticsearch.search.SearchHit;

import org.elasticsearch.search.builder.SearchSourceBuilder;

import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;

import org.elasticsearch.search.fetch.subphase.highlight.HighlightField;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import org.springframework.util.CollectionUtils;

import cn.fss.elasticsearch.domain.SearchReq;

import cn.fss.common.core.page.TableDataInfo;

import cn.fss.common.utils.uuid.UUID;

import cn.fss.elasticsearch.ElasticSearchClient;

import cn.fss.elasticsearch.domain.DocumentObj;

import cn.fss.elasticsearch.service.ISearchSerice;

import lombok.extern.slf4j.Slf4j;

@Service

@Slf4j

public class SearchServiceImpl implements ISearchSerice {

复制代码

@Autowired
private ElasticSearchClient esClient;

@Override
public TableDataInfo search(SearchReq req) {
    String keyword = req.getKeyword();//关键字
          //分页，采用from+size方式，其他方式网上搜索                  
    Integer pageSize  =req.getPageSize();
    Integer pageNum = req.getPageNum();
    Integer from = (pageNum-1)*pageSize;
    // 高亮查询，关键词添加红色样式
    HighlightBuilder highlightBuilder = new HighlightBuilder().field("attachment.content")
            .preTags("<font color='red' font-weight='bold'>").postTags("</font>");
    // 普通全索引查询
    SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder()
            .query(QueryBuilders.matchQuery("attachment.content", keyword).analyzer("ik_smart"))
            .from(from).size(pageSize) //分页
            .trackTotalHits(true) //返回总数
            .highlighter(highlightBuilder);
    TableDataInfo datas = esClient.selectDocumentList("docwrite", searchSourceBuilder);
    if(datas==null || CollectionUtils.isEmpty(datas.getRows())) {
        return null;
    }
    Long total = datas.getTotal();//总命中数
    
    @SuppressWarnings("unchecked")
    List<SearchHit> searchHits = (List<SearchHit>) datas.getRows();
    
    // 处理每一条记录(每一个文档)，获得高亮文本。
    List<DocumentObj> results = new ArrayList<>();
    for (SearchHit hit : searchHits) {
        Map<String, Object> sourceAsMap = hit.getSourceAsMap();
        DocumentObj obj = new DocumentObj();
        obj.setDocId(((Integer) sourceAsMap.get("docId")).intValue());
        obj.setDocName((String) sourceAsMap.get("docName"));
        obj.setDocType((String) sourceAsMap.get("docType"));
        obj.setTitle((String) sourceAsMap.get("title"));

        HighlightField contentHighlightField = hit.getHighlightFields().get("attachment.content");
        // 对于一个文档，它的高亮文本有多个结果，这里只拼接前2个结果。
        Text[] fragments = contentHighlightField.fragments();
        StringBuffer highLightMessage = new StringBuffer();
        if (fragments != null && fragments.length > 0) {
            for (Text t : fragments) {
                highLightMessage.append(t.toString()).append("|");
            }
        }
        if (StringUtils.isNoneBlank(highLightMessage.toString())) {
            obj.setContent(highLightMessage.toString());
            results.add(obj);

        }
    }
    TableDataInfo rst = new TableDataInfo();
    rst.setRows(results);
    rst.setTotal(total);
    return rst;

}

@Override
public Boolean uploadFile(DocumentObj data) {
    try {
        //String id = UUID.randomUUID().toString().replaceAll("-", "").toUpperCase();
        Boolean rst= esClient.insertDocument("docwrite",data.getDocId()+"", data);
        return rst;
        
    } catch (Exception ex) {
        log.error(ex.getMessage(), ex);
    }
    return false;
}

@Override
public boolean deleteDocumnet(String index, String docId) {
    return esClient.deleteDocument(index, docId);
}

}