最近有个朋友咨询如何实现对海量磁盘资料进行目录、文件名及文件正文进行搜索，要求实现简单高效、维护方便、成本低廉。我想了想利用ES来实现文档的索引及搜索是适当的选择，于是就着手写了一些代码来实现，下面就将设计思路及实现方法作以介绍。
整体架构
考虑到磁盘文件分布到不同的设备上，所以采用磁盘扫瞄代理的模式构建系统，即把扫描服务以代理的方式部署到目标磁盘所在的服务器上，作为定时任务执行，索引统一建立到ES中，当然ES采用分布式高可用部署方法，搜索服务和扫描代理部署到一起来简化架构并实现分布式能力。
磁盘文件快速检索架构
部署ES
ES（elasticsearch）是本项目唯一依赖的第三方软件，ES支持docker方式部署，以下是部署过程
docker pull docker.elastic.co/elasticsearch/elasticsearch:6.3.2
docker run -e ES_JAVA_OPTS="-Xms256m -Xmx256m" -d -p 9200:9200 -p 9300:9300 --name es01 docker.elastic.co/elasticsearch/elasticsearch:6.3.2
部署完成后，通过浏览器打开http://localhost:9200，如果正常打开，出现如下界面，则说明ES部署成功。
ES界面
工程结构
工程结构
依赖包
本项目除了引入springboot的基础starter外，还需要引入ES相关包
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-elasticsearch</artifactId>
</dependency>
<dependency>
<groupId>io.searchbox</groupId>
<artifactId>jest</artifactId>
<version>5.3.3</version>
</dependency>
<dependency>
<groupId>net.sf.jmimemagic</groupId>
<artifactId>jmimemagic</artifactId>
<version>0.1.4</version>
</dependency>
</dependencies>
配置文件
需要将ES的访问地址配置到application.yml里边，同时为了简化程序，需要将待扫描磁盘的根目录（index-root）配置进去，后面的扫描任务就会递归遍历该目录下的全部可索引文件。
server:
port: @elasticsearch.port@
spring:
application:
name: @project.artifactId@
profiles:
active: dev
elasticsearch:
jest:
uris: http://127.0.0.1:9200
index-root: /Users/crazyicelee/mywokerspace
索引结构数据定义
因为要求文件所在目录、文件名、文件正文都有能够检索，所以要将这些内容都作为索引字段定义，而且添加ES client要求的JestId来注解id。
package com.crazyice.lee.accumulation.search.data;
import io.searchbox.annotations.JestId;
import lombok.Data;
@Data
public class Article {
@JestId
private Integer id;
private String author;
private String title;
private String path;
private String content;
private String fileFingerprint;
}
扫描磁盘并创建索引
因为要扫描指定目录下的全部文件，所以采用递归的方法遍历该目录，并标识已经处理的文件以提升效率，在文件类型识别方面采用两种方式可供选择，一个是文件内容更为精准判断（Magic），一种是以文件扩展名粗略判断。这部分是整个系统的核心组件。
这里有个小技巧
对目标文件内容计算MD5值并作为文件指纹存储到ES的索引字段里边，每次在重建索引的时候判断该MD5是否存在，如果存在就不用重复建立索引了，可以避免文件索引重复，也能避免系统重启后重复遍历文件。
package com.crazyice.lee.accumulation.search.service;
import com.alibaba.fastjson.JSONObject;
import com.crazyice.lee.accumulation.search.data.Article;
import com.crazyice.lee.accumulation.search.utils.Md5CaculateUtil;
import io.searchbox.client.JestClient;
import io.searchbox.core.Index;
import io.searchbox.core.Search;
import io.searchbox.core.SearchResult;
import lombok.extern.slf4j.Slf4j;
import net.sf.jmimemagic.*;
import org.apache.poi.hwpf.extractor.WordExtractor;
import org.apache.poi.xwpf.extractor.XWPFWordExtractor;
import org.apache.poi.xwpf.usermodel.XWPFDocument;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
@Component
@Slf4j
public class DirectoryRecurse {
@Autowired
private JestClient jestClient;
//读取文件内容转换为字符串
private String readToString(File file, String fileType) {
StringBuffer result = new StringBuffer();
switch (fileType) {
case "text/plain":
case "java":
case "c":
case "cpp":
case "txt":
try (FileInputStream in = new FileInputStream(file)) {
Long filelength = file.length();
byte[] filecontent = new byte[filelength.intValue()];
in.read(filecontent);
result.append(new String(filecontent, "utf8"));
} catch (FileNotFoundException e) {
log.error("{}", e.getLocalizedMessage());
} catch (IOException e) {
log.error("{}", e.getLocalizedMessage());
}
break;
case "doc":
//使用HWPF组件中WordExtractor类从Word文档中提取文本或段落
try (FileInputStream in = new FileInputStream(file)) {
WordExtractor extractor = new WordExtractor(in);
result.append(extractor.getText());
} catch (Exception e) {
log.error("{}", e.getLocalizedMessage());
}
break;
case "docx":
try (FileInputStream in = new FileInputStream(file); XWPFDocument doc = new XWPFDocument(in)) {
XWPFWordExtractor extractor = new XWPFWordExtractor(doc);
result.append(extractor.getText());
} catch (Exception e) {
log.error("{}", e.getLocalizedMessage());
}
break;
}
return result.toString();
}
//判断是否已经索引
private JSONObject isIndex(File file) {
JSONObject result = new JSONObject();
//用MD5生成文件指纹,搜索该指纹是否已经索引
String fileFingerprint = Md5CaculateUtil.getMD5(file);
result.put("fileFingerprint", fileFingerprint);
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.termQuery("fileFingerprint", fileFingerprint));
Search search = new Search.Builder(searchSourceBuilder.toString()).addIndex("diskfile").addType("files").build();
try {
//执行
SearchResult searchResult = jestClient.execute(search);
if (searchResult.getTotal() > 0) {
result.put("isIndex", true);
} else {
result.put("isIndex", false);
}
} catch (IOException e) {
log.error("{}", e.getLocalizedMessage());
}
return result;
}
//对文件目录及内容创建索引
private void createIndex(File file, String method) {
//忽略掉临时文件，以~$起始的文件名
if (file.getName().startsWith("~$")) return;
String fileType = null;
switch (method) {
case "magic":
Magic parser = new Magic();
try {
MagicMatch match = parser.getMagicMatch(file, false);
fileType = match.getMimeType();
} catch (MagicParseException e) {
//log.error("{}",e.getLocalizedMessage());
} catch (MagicMatchNotFoundException e) {
//log.error("{}",e.getLocalizedMessage());
} catch (MagicException e) {
//log.error("{}",e.getLocalizedMessage());
}
break;
case "ext":
String filename = file.getName();
String[] strArray = filename.split("\\.");
int suffixIndex = strArray.length - 1;
fileType = strArray[suffixIndex];
}
switch (fileType) {
case "text/plain":
case "java":
case "c":
case "cpp":
case "txt":
case "doc":
case "docx":
JSONObject isIndexResult = isIndex(file);
log.info("文件名：{}，文件类型：{}，MD5：{}，建立索引：{}", file.getPath(), fileType, isIndexResult.getString("fileFingerprint"), isIndexResult.getBoolean("isIndex"));
if (isIndexResult.getBoolean("isIndex")) break;
//1. 给ES中索引(保存)一个文档
Article article = new Article();
article.setTitle(file.getName());
article.setAuthor(file.getParent());
article.setPath(file.getPath());
article.setContent(readToString(file, fileType));
article.setFileFingerprint(isIndexResult.getString("fileFingerprint"));
//2. 构建一个索引
Index index = new Index.Builder(article).index("diskfile").type("files").build();
try {
//3. 执行
if (!jestClient.execute(index).getId().isEmpty()) {
log.info("构建索引成功！");
}
} catch (IOException e) {
log.error("{}", e.getLocalizedMessage());
}
break;
}
}
public void find(String pathName) throws IOException {
//获取pathName的File对象
File dirFile = new File(pathName);
//判断该文件或目录是否存在，不存在时在控制台输出提醒
if (!dirFile.exists()) {
log.info("do not exit");
return;
}
//判断如果不是一个目录，就判断是不是一个文件，时文件则输出文件路径
if (!dirFile.isDirectory()) {
if (dirFile.isFile()) {
createIndex(dirFile, "ext");
}
return;
}
//获取此目录下的所有文件名与目录名
String[] fileList = dirFile.list();
for (int i = 0; i < fileList.length; i++) {
//遍历文件目录
String string = fileList[i];
File file = new File(dirFile.getPath(), string);
//如果是一个目录，输出目录名后，进行递归
if (file.isDirectory()) {
//递归
find(file.getCanonicalPath());
} else {
createIndex(file, "ext");
}
}
}
}
扫描任务
这里采用定时任务的方式来扫描指定目录以实现动态增量创建索引。
package com.crazyice.lee.accumulation.search.service;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import java.io.IOException;
@Configuration
@Component
@Slf4j
public class CreateIndexTask {
@Autowired
private DirectoryRecurse directoryRecurse;
@Value("${index-root}")
private String indexRoot;
@Scheduled(cron = "* 0/5 * * * ?")
private void addIndex(){
try {
directoryRecurse.find(indexRoot);
directoryRecurse.writeIndexStatus();
} catch (IOException e) {
log.error("{}",e.getLocalizedMessage());
}
}
}
搜索服务
这里以restFul的方式提供搜索服务，将关键字以高亮度模式提供给前端UI，浏览器端可以根据返回的JSON进行展示。
package com.crazyice.lee.accumulation.search.web;
import com.alibaba.fastjson.JSONObject;
import com.crazyice.lee.accumulation.search.data.Article;
import io.searchbox.client.JestClient;
import io.searchbox.core.Search;
import io.searchbox.core.SearchResult;
import io.swagger.annotations.ApiImplicitParam;
import io.swagger.annotations.ApiImplicitParams;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.lang.NonNull;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
@RestController
@Slf4j
public class Controller {
@Autowired
private JestClient jestClient;
@RequestMapping(value = "/search/{keyword}",method = RequestMethod.GET)
@ApiOperation(value = "全部字段搜索关键字",notes = "es验证")
@ApiImplicitParams(
@ApiImplicitParam(name = "keyword",value = "全文检索关键字",required = true,paramType = "path",dataType = "String")
)
public List search(@PathVariable String keyword){
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.queryStringQuery(keyword));
HighlightBuilder highlightBuilder = new HighlightBuilder();
//path属性高亮度
HighlightBuilder.Field highlightPath = new HighlightBuilder.Field("path");
highlightPath.highlighterType("unified");
highlightBuilder.field(highlightPath);
//title字段高亮度
HighlightBuilder.Field highlightTitle = new HighlightBuilder.Field("title");
highlightTitle.highlighterType("unified");
highlightBuilder.field(highlightTitle);
//content字段高亮度
HighlightBuilder.Field highlightContent = new HighlightBuilder.Field("content");
highlightContent.highlighterType("unified");
highlightBuilder.field(highlightContent);
//高亮度配置生效
searchSourceBuilder.highlighter(highlightBuilder);
log.info("搜索条件{}",searchSourceBuilder.toString());
//构建搜索功能
Search search = new Search.Builder(searchSourceBuilder.toString()).addIndex( "gf" ).addType( "news" ).build();
try {
//执行
SearchResult result = jestClient.execute( search );
return result.getHits(Article.class);
} catch (IOException e) {
log.error("{}",e.getLocalizedMessage());
}
return null;
}
}
搜索restFul结果测试
这里以swagger的方式进行API测试。其中keyword是全文检索中要搜索的关键字。
搜索结果
使用thymeleaf生成UI
集成thymeleaf的模板引擎直接将搜索结果以web方式呈现。模板包括主搜索页和搜索结果页，通过@Controller注解及Model对象实现。
<body>
<div class="container">
<div class="header">
<form action="./search" class="parent">
<input type="keyword" name="keyword" th:value="${keyword}">
<input type="submit" value="搜索">
</form>
</div>
<div class="content" th:each="article,memberStat:${articles}">
<div class="c_left">
<p class="con-title" th:text="${article.title}"/>
<p class="con-path" th:text="${article.path}"/>
<p class="con-preview" th:utext="${article.highlightContent}"/>
<a class="con-more">更多</a>
</div>
<div class="c_right">
<p class="con-all" th:utext="${article.content}"/>
</div>
</div>
<script language="JavaScript">
document.querySelectorAll('.con-more').forEach(item => {
item.onclick = () => {
item.style.cssText = 'display: none';
item.parentNode.querySelector('.con-preview').style.cssText = 'max-height: none;';
}});
</script>
</div>
