使用GridFS實現文件的上傳和下載
在這篇博客中，我們將展示如何使用Spring Boot中使用mongodb自帶的文件存儲系統GridFS實現文件的上傳和下載功能
首先了解一下怎么用命令操作GridFS
安裝mongodb
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sudo apt-get install mongodb |
安裝完成后找到mongofiles的位置
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whereis mongofiles |
找到之后進入目錄就可以上傳文件了
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mongofiles put /home/ubuntu/Desktop/1.jpg |
這時文件就添加成功了，進入mongodb查看
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mongoshow dbs # 發現多了一個gridfsuse gridfsdb.fs.files.find() # 存放文件的一些基本信息db.fs.chunks.find() # 存放文件二進制內容，一個文件有多個fs.chunks，每個fs.chunks都有一個，files_id與fs.files中的id相對應，形成多對一的關系，文件存的時候分開存，取的時候再合并 |
使用Spring Boot操作GridFS
引入依賴
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<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-mongodb</artifactId></dependency><dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.4</version></dependency> |
controller代碼
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import com.mongodb.BasicDBObject;import com.mongodb.DBObject;import com.mongodb.client.gridfs.GridFSBucket;import com.mongodb.client.gridfs.GridFSDownloadStream;import com.mongodb.client.gridfs.GridFSFindIterable;import com.mongodb.client.gridfs.model.GridFSFile;import org.apache.commons.io.IOUtils;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.data.mongodb.gridfs.GridFsOperations;import org.springframework.data.mongodb.gridfs.GridFsResource;import org.springframework.data.mongodb.gridfs.GridFsTemplate;import org.springframework.http.MediaType;import org.springframework.http.ResponseEntity;import org.springframework.web.bind.annotation.*;import org.springframework.web.multipart.MultipartFile;import java.io.IOException;import java.io.InputStream;import static org.springframework.data.mongodb.core.query.Query.query;import static org.springframework.data.mongodb.gridfs.GridFsCriteria.whereFilename;@RestControllerpublic class ImageController { @Autowired private GridFsTemplate gridFsTemplate; @Autowired private GridFsOperations operations; @Autowired private GridFSBucket gridFSBucket; @PostMapping("file/upload") public ImageResponse upload(@RequestParam("file") MultipartFile file) { DBObject metaData = new BasicDBObject(); // 把時間戳作為文件名存入mongodb String fileName = String.valueOf(System.currentTimeMillis()); InputStream inputStream = null; try { inputStream = file.getInputStream(); gridFsTemplate.store(inputStream, fileName, "image", metaData); } catch (IOException e) { throw new RuntimeException(); } return new ImageResponse(fileName); } @GetMapping(value = "file/download/${fileName}", produces = MediaType.IMAGE_JPEG_VALUE) @ResponseBody public byte[] getImage(@PathVariable("fileName") String fileName) throws IOException { if (fileName == null) { return null; } // 根據文件名查詢(也可以根據md5值等信息查詢) GridFSFindIterable result = operations.find(query(whereFilename().is(fileName))); GridFSFile gridFSFile = result.first(); GridFSDownloadStream gridFSDownloadStream = gridFSBucket.openDownloadStream(gridFSFile.getObjectId()); //創建gridFsResource，用于獲取流對象 GridFsResource gridFsResource = new GridFsResource(gridFSFile, gridFSDownloadStream); return IOUtils.toByteArray(gridFsResource.getInputStream()); }} |
加入一個配置類
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import com.mongodb.MongoClient;import com.mongodb.client.MongoDatabase;import com.mongodb.client.gridfs.GridFSBucket;import com.mongodb.client.gridfs.GridFSBuckets;import org.springframework.beans.factory.annotation.Value;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;@Configurationpublic class MongoConfig { @Value("${spring.data.mongodb.database}") String db; @Bean public GridFSBucket getGridFSBucket(MongoClient mongoClient){ MongoDatabase database = mongoClient.getDatabase(db); GridFSBucket bucket = GridFSBuckets.create(database); return bucket; }} |
圖片返回的實體類
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public class ImageResponse implements Serializable { private String imageName; public ImageResponse(String imageName) { this.imageName = imageName; } public String getImageName() { return imageName; } public void setImageName(String imageName) { this.imageName = imageName; }} |
配置文件
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spring: data: mongodb: uri: mongodb://localhost:27017/gridfs database: gridfs |
Spring Boot中使用GridFS
什么是GridFS
GirdFS是MongoDB提供的用于持久化存儲文件的模塊
在GridFS存儲文件是將文件分塊存儲，文件會按照256KB的大小分割成多個塊進行存儲，GridFS使用兩個集合 (collection)存儲文件，一個集合是chunks, 用于存儲文件的二進制數據;一個集合是files，用于存儲文件的元數 據信息(文件名稱、塊大小、上傳時間等信息)。
從GridFS中讀取文件要對文件的各各塊進行組裝、合并。
在SpringBoot中使用GridFS
存儲文件
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@AutowiredGridFsTemplate gridFsTemplate;@Testpublic void GridFsTest() throws FileNotFoundException { //選擇要存儲的文件 File file = new File("/Users/xxx/Desktop/xxx.docx"); InputStream inputStream = new FileInputStream(file); //存儲文件并起名稱 ObjectId objectId = gridFsTemplate.store(inputStream, "面試寶典"); String id = objectId.toString(); //獲取到文件的id，可以從數據庫中查找 System.out.println(id);} |
查找文件
創建GridFSBucket對象
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@Configurationpublic class MongoConfig { @Value("${spring.data.mongodb.database}") String db; @Bean public GridFSBucket getGridFSBucket(MongoClient mongoClient){ MongoDatabase mongoDatabase = mongoClient.getDatabase(db); GridFSBucket bucket = GridFSBuckets.create(mongoDatabase); return bucket; }} |
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@AutowiredGridFsTemplate gridFsTemplate;@AutowiredGridFSBucket gridFSBucket;@Testpublic void queryFile() throws IOException { String id = "5c1b8fac72884e389ae3df82"; //根據id查找文件 GridFSFile gridFSFile = gridFsTemplate.findOne(new Query(Criteria.where("_id").is(id))); //打開下載流對象 GridFSDownloadStream gridFS = gridFSBucket.openDownloadStream(gridFSFile.getObjectId()); //創建gridFsSource，用于獲取流對象 GridFsResource gridFsResource = new GridFsResource(gridFSFile,gridFS); //獲取流中的數據 String string = IOUtils.toString(gridFsResource.getInputStream(), "UTF-8"); System.out.println(string);} |
刪除文件
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//刪除文件@Testpublic void testDelFile() throws IOException {//根據文件id刪除fs.files和fs.chunks中的記錄 gridFsTemplate.delete(Query.query(Criteria.where("_id").is("5c1b8fac72884e389ae3df82")));} |
以上為個人經驗，希望能給大家一個參考，也希望大家多多支持服務器之家。
原文鏈接：https://blog.csdn.net/qq_44693282/article/details/97916541
