Java调用Elasticsearch API实现全文检索，搭配MinIO文件存储

Dear 丶 2024-03-31 16:58 47阅读 0赞

应用背景：  
对存储在MinIO服务器的文件实现全文检索。也可以是其他服务器或本地文件，本文仅详细介绍MinIO文件的读取及转换。通过Elasticsearch的Ingest-Attachment插件抽取文件内容，支持Word、Excel、PDF、TXT等格式文件，无需手动解析文件内容。

上代码，详细解释可以阅读注释、

1.引入依赖

springboot已经管理好了依赖，只需引入spring-boot-starter-data-elasticsearch

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

![523c358db4a3411392bb58981326fcf5.png][]

2.配置文件

elasticsearch:
      host: 192.168.2.154
      port: 9200

3.配置类

@Setter
    @ConfigurationProperties(prefix = "elasticsearch")
    @Configuration
    public class ElasticSearchConfig {
    
        private String host;
    
        private Integer port;
    
        @Bean
        public RestHighLevelClient restHighLevelClient(){
            RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(new HttpHost(this.host, this.port)));
            return client;
        }
    }

4.实现类

package com.dmp.document.service.impl;
    
    import com.alibaba.fastjson2.JSONObject;
    import com.dmp.common.constant.HttpStatus;
    import com.dmp.common.core.page.PageDomain;
    import com.dmp.common.core.page.TableDataInfo;
    import com.dmp.common.core.page.TableSupport;
    import com.dmp.document.domain.dto.DocElasticsearchDto;
    import com.dmp.document.domain.entity.DocDocument;
    import com.dmp.document.service.DocDocumentService;
    import com.dmp.document.service.ElasticsearchService;
    import com.dmp.document.service.MinioClientService;
    import com.dmp.system.service.ISysConfigService;
    import lombok.extern.slf4j.Slf4j;
    import org.apache.commons.compress.utils.IOUtils;
    import org.elasticsearch.action.delete.DeleteRequest;
    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.xcontent.XContentType;
    import org.elasticsearch.index.query.BoolQueryBuilder;
    import org.elasticsearch.index.query.MultiMatchQueryBuilder;
    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.elasticsearch.common.text.Text;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import java.io.*;
    import java.net.HttpURLConnection;
    import java.net.URL;
    import java.util.*;
    
    import static com.sun.webkit.network.URLs.newURL;
    import static org.elasticsearch.client.RequestOptions.DEFAULT;
    
    /**
     * @author daixin
     * @version 1.0
     * @description: TODO
     * @date 2022/11/23 17:38
     */
    @Slf4j
    @Service
    public class ElasticsearchServiceImpl implements ElasticsearchService {
        @Autowired
        private RestHighLevelClient esClient;
    
        @Autowired
        private MinioClientService minioClientService;
    
        @Autowired
        private DocDocumentService docDocumentService;
    
        @Autowired
        private ISysConfigService sysConfigService;
    
    
        public String createFileIndex(String id, String projectId) throws Exception {
            String result = null;
            InputStream is = null;
            try{
                Date date1 = new Date();
                //查询系统内存储的文件key
                DocDocument docDocument = docDocumentService.getById(id);
                String path = docDocument.getPath();
                //获取minio下载签名
                String url = minioClientService.getDownloadLink("file-bucket",path);
                //请求minio获取文件流
                URL url2= newURL(url);
                HttpURLConnection conn=(HttpURLConnection) url2.openConnection();
                conn.setDoInput(true);
                conn.connect();
                is = conn.getInputStream();
                //转码base64
                byte[] fileByteStream = IOUtils.toByteArray(is);
                String base64String = new String(Base64.getEncoder().encodeToString(fileByteStream).getBytes(), "UTF-8");
                //封装ES请求
                IndexRequest request;
                Map attachmentMap = new HashMap();
                attachmentMap.put("data", base64String);
                attachmentMap.put("fileName", docDocument.getName());
                attachmentMap.put("projectId",projectId);
                //查询系统参数
                String esIndex = sysConfigService.selectConfigByKey("es_index");
                String esPipe = sysConfigService.selectConfigByKey("es_pipe");
                //配置查询请求参数
                request = new IndexRequest(esIndex);
                request.id(String.valueOf(docDocument.getId()));
                request.setPipeline(esPipe);//文件抽取管道，需提前创建
                request.source(JSONObject.toJSONString(attachmentMap), XContentType.JSON);
                IndexResponse response = esClient.index(request, RequestOptions.DEFAULT);
                response.status().toString();
                Date date2 = new Date();
                log.info("创建索引-----耗时：{}ms" , (date2.getTime() - date1.getTime()));
            }catch(Exception e){
                throw e;
            }finally {
                is.close();
            }
            return result;
        }
        @Override
        public TableDataInfo matchContent(String content, String projectId) {
            //此处为若依框架提供的分页，可改为你自己的分页
            PageDomain pageDomain = TableSupport.buildPageRequest();
            Integer pageNum = pageDomain.getPageNum();
            Integer pageSize = pageDomain.getPageSize();
            TableDataInfo rspData = new TableDataInfo();
            rspData.setCode(HttpStatus.SUCCESS);
            rspData.setMsg("查询成功");
            //查询系统参数
            String esIndex = sysConfigService.selectConfigByKey("es_index");
            SearchRequest searchRequest = new SearchRequest(esIndex);
            //布尔查询,检索标题和内容,过滤项目id
            SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
            MultiMatchQueryBuilder matchQueryBuilder = QueryBuilders.multiMatchQuery(content, "attachment.content","fileName");
            BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
            boolQueryBuilder.must(matchQueryBuilder);
            if(projectId != null){
                boolQueryBuilder.filter(QueryBuilders.termQuery("projectId", projectId));
            }
            sourceBuilder.query(boolQueryBuilder);
            //配置高亮
            HighlightBuilder highlightBuilder = new HighlightBuilder();
            highlightBuilder.field("attachment.content"); //content字段高亮
            highlightBuilder.field("fileName");//fileName字段高亮
            highlightBuilder.preTags("<span style='color:red'>"); //高亮前缀
            highlightBuilder.postTags("</span>"); //高亮后缀
            sourceBuilder.highlighter(highlightBuilder);
            //分页查询
            sourceBuilder.from((pageNum-1)*pageSize).size(pageSize);
            searchRequest.source(sourceBuilder);
            SearchResponse searchResponse = null;
            try {
                searchResponse = esClient.search(searchRequest, DEFAULT);
            } catch (Throwable e) {
                //捕捉最高级别异常，确保打印详细信息
                e.printStackTrace();
            }
            if(searchResponse.getHits() == null){
                rspData.setTotal(0);
                rspData.setRows(null);
                return rspData;
            }
            List<DocElasticsearchDto> docElasticsearchList = new ArrayList<>();
            Long totalHits = searchResponse.getHits().getTotalHits().value;//匹配总条数，用于分页显示
            for (SearchHit hit : searchResponse.getHits()){
                //查询结果
                String source = hit.getSourceAsString();
                DocElasticsearchDto docElasticsearchDto = JSONObject.parseObject(source, DocElasticsearchDto.class);
                docElasticsearchDto.setId(hit.getId());
                //处理高亮字段
                Map<String, HighlightField> map = hit.getHighlightFields();
                if(map.containsKey("attachment.content")) {
                    StringBuilder matchContent = new StringBuilder();
                    for(Text t : map.get("attachment.content").fragments()){
                        matchContent.append(t.toString());
                    }
                    docElasticsearchDto.getAttachment().put("content",matchContent.toString());
                }
                if(map.containsKey("fileName")) {
                    StringBuilder matchFileName =  new StringBuilder();
                    for(Text t : map.get("fileName").fragments()){
                        matchFileName.append(t.toString());
                    }
                    docElasticsearchDto.setFileName(matchFileName.toString());
                }
                docElasticsearchList.add(docElasticsearchDto);
            }
            rspData.setTotal(totalHits);
            rspData.setRows(docElasticsearchList);
            return rspData;
        }
        @Override
        public void deleteFileIndex(String id) throws IOException {
            //查询系统参数,ES索引名称
            String esIndex = sysConfigService.selectConfigByKey("es_index");
            //删除索引
            DeleteRequest deleteRequest = new DeleteRequest(esIndex,id);
            esClient.delete(deleteRequest, RequestOptions.DEFAULT);
        }
    
    }

示例的实现是先从数据库查询到保存的文件信息，然后从minio文件存储服务器获取文件流，由于minio提供以签名的方式获取流，这里就直接使用了，你也可以是其他服务器，或者直接获取文件对象。在创建索引的时候直接发送文件流，Ingest-Attachment插件会帮你实现转换。Ingest-Attachment的安装可参考[Docker安装Elasticsearch及相关插件详细步骤，全程亲测避坑\_冰糖码奇朵的博客-CSDN博客][Docker_Elasticsearch_-CSDN]

[523c358db4a3411392bb58981326fcf5.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/8d2346cc1c084bd18605e0db9807c474.png
[Docker_Elasticsearch_-CSDN]: https://blog.csdn.net/secretdaixin/article/details/128201184