使用GridFS实现文件的上传和下载
在这篇博客中,我们将展示如何使用Spring Boot中使用mongodb自带的文件存储系统GridFS实现文件的上传和下载功能
首先了解一下怎么用命令操作GridFS
安装mongodb
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sudo apt-get install mongodb |
安装完成后找到mongofiles的位置
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whereis mongofiles |
找到之后进入目录就可以上传文件了
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mongofiles put /home/ubuntu/Desktop/ 1 .jpg |
这时文件就添加成功了,进入mongodb查看
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mongo show dbs # 发现多了一个gridfs use gridfs db.fs.files.find() # 存放文件的一些基本信息 db.fs.chunks.find() # 存放文件二进制内容,一个文件有多个fs.chunks,每个fs.chunks都有一个,files_id与fs.files中的id相对应,形成多对一的关系,文件存的时候分开存,取的时候再合并 |
使用Spring Boot操作GridFS
引入依赖
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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代码
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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; @RestController public 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(); // 把时间戳作为文件名存入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/${fileName}" , produces = MediaType.IMAGE_JPEG_VALUE) @ResponseBody public byte [] getImage( @PathVariable ( "fileName" ) String fileName) throws IOException { if (fileName == null ) { return null ; } // 根据文件名查询(也可以根据md5值等信息查询) GridFSFindIterable result = operations.find(query(whereFilename().is(fileName))); GridFSFile gridFSFile = result.first(); GridFSDownloadStream gridFSDownloadStream = gridFSBucket.openDownloadStream(gridFSFile.getObjectId()); //创建gridFsResource,用于获取流对象 GridFsResource gridFsResource = new GridFsResource(gridFSFile, gridFSDownloadStream); return IOUtils.toByteArray(gridFsResource.getInputStream()); } } |
加入一个配置类
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import com.mongodb.MongoClient; import com.mongodb.client.MongoDatabase; import com.mongodb.client.gridfs.GridFSBucket; import com.mongodb.client.gridfs.GridFSBuckets; import org.springframework.beans.factory.annotation.Value; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration public class MongoConfig { @Value ( "${spring.data.mongodb.database}" ) String db; @Bean public GridFSBucket getGridFSBucket(MongoClient mongoClient){ MongoDatabase database = mongoClient.getDatabase(db); GridFSBucket bucket = GridFSBuckets.create(database); return bucket; } } |
图片返回的实体类
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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储文件的模块
在GridFS存储文件是将文件分块存储,文件会按照256KB的大小分割成多个块进行存储,GridFS使用两个集合 (collection)存储文件,一个集合是chunks, 用于存储文件的二进制数据;一个集合是files,用于存储文件的元数 据信息(文件名称、块大小、上传时间等信息)。
从GridFS中读取文件要对文件的各各块进行组装、合并。
在SpringBoot中使用GridFS
存储文件
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@Autowired GridFsTemplate gridFsTemplate; @Test public void GridFsTest() throws FileNotFoundException { //选择要存储的文件 File file = new File( "/Users/xxx/Desktop/xxx.docx" ); InputStream inputStream = new FileInputStream(file); //存储文件并起名称 ObjectId objectId = gridFsTemplate.store(inputStream, "面试宝典" ); String id = objectId.toString(); //获取到文件的id,可以从数据库中查找 System.out.println(id); } |
查找文件
创建GridFSBucket对象
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@Configuration public 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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@Autowired GridFsTemplate gridFsTemplate; @Autowired GridFSBucket gridFSBucket; @Test public void queryFile() throws IOException { String id = "5c1b8fac72884e389ae3df82" ; //根据id查找文件 GridFSFile gridFSFile = gridFsTemplate.findOne( new Query(Criteria.where( "_id" ).is(id))); //打开下载流对象 GridFSDownloadStream gridFS = gridFSBucket.openDownloadStream(gridFSFile.getObjectId()); //创建gridFsSource,用于获取流对象 GridFsResource gridFsResource = new GridFsResource(gridFSFile,gridFS); //获取流中的数据 String string = IOUtils.toString(gridFsResource.getInputStream(), "UTF-8" ); System.out.println(string); } |
删除文件
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//删除文件 @Test public void testDelFile() throws IOException { //根据文件id删除fs.files和fs.chunks中的记录 gridFsTemplate.delete(Query.query(Criteria.where( "_id" ).is( "5c1b8fac72884e389ae3df82" ))); } |
以上为个人经验,希望能给大家一个参考,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/qq_44693282/article/details/97916541