springboot2.x对mongoDB的集成

springboot2.x对mongoDB的集成

需引入import com.mongodb.client.gridfs.model.GridFSFile;这个包
/**

• 1.文件上传：与springboot1.x一样
  /
  (只列出核心代码)
  gridFsTemplate.store(file.getInputStream(),file.getOriginalFilename(),file.getContentType());
  /
  *2.下载
  */
  gridFsTemplate.findOne(query)返回类型由GridFSDBFile改为GridFSFile导致的问题：文件下载时下面的代码不可用
  GridFSDBFile gridFSDBFile = new GridFSDBFile();
  gridFSDBFile.writeTo(response.getOutputStream())
  解决办法：将GridFSFile转换为GridFsResource
  转换类：
  package com.example.myallprogram.modules;

import com.mongodb.client.MongoDatabase;
import com.mongodb.client.gridfs.GridFSBucket;
import com.mongodb.client.gridfs.GridFSBuckets;
import com.mongodb.client.gridfs.GridFSDownloadStream;
import com.mongodb.client.gridfs.model.GridFSFile;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.MongoDbFactory;
import org.springframework.data.mongodb.gridfs.GridFsResource;
import org.springframework.stereotype.Component;

@Component(“gridConfig”)
@Configuration
public class GridConfig {
@Autowired
private MongoDbFactory mongoDbFactory;
@Autowired
private GridFSBucket gridFSBucket;

@Bean
public GridFSBucket getGridFSBuckets() {
    MongoDatabase db = mongoDbFactory.getDb();
    return GridFSBuckets.create(db);
}
// 将GridFSFile 转成 GridFsResource
public GridFsResource convertGridFSFile2Resource(GridFSFile gridFsFile) {
    GridFSDownloadStream gridFSDownloadStream = gridFSBucket.openDownloadStream(gridFsFile.getObjectId());
    return new GridFsResource(gridFsFile, gridFSDownloadStream);
}

}
下载方法：
@RequestMapping(value = “/downloadFile”,method = RequestMethod.GET)
public void downloadFile(@RequestParam(name = “fileName”) String fileName, HttpServletResponse response) throws Exception {
GridFSFile gridFSFile = gridFsTemplate.findOne(new Query().addCriteria(Criteria.where(“filename”).is(fileName)));
GridFsResource fsResource = gridConfig.convertGridFSFile2Resource(gridFSFile);
IOUtils.copy(fsResource.getInputStream(),response.getOutputStream());
}
/*
*3.删除
*删除时需要@ResponseBody注解
*/
@RequestMapping(value="/deleteFile",method = RequestMethod.POST)
@ResponseBody
public void deleteFromMongo(@RequestParam(name=“fileName”) String fileName){
gridFsTemplate.delete(Query.query(Criteria.where(“filename”).is(fileName)));
}