Spring Boot使用GridFS实现文件的上传和下载

Spring Boot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

sudo apt-get install mongodb

安装完成后找到mongofiles的位置

whereis mongofiles

找到之后进入目录就可以上传文件了

mongofiles put /home/ubuntu/Desktop/1.jpg

这时文件就添加成功了，进入mongodb查看

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

<dependency>
	<groupId>org.springframework.bootgroupId>
	<artifactId>spring-boot-starter-data-mongodbartifactId>
dependency>
<dependency>
	<groupId>commons-iogroupId>
    <artifactId>commons-ioartifactId>
    <version>2.4version>
dependency>

controller代码

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

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

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

spring:
  data:
    mongodb:
      uri: mongodb://localhost:27017/gridfs
      database: gridfs