Java项目中对MongoDB数据库进行文件上传

在mongo-java-driver3.x以上的版本中逐渐弃用了Mongo和getDB等一系列方法，所以原来的GridFS的用法也发生了一些改变

改进前：

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.MongoClient;
import com.mongodb.gridfs.GridFS;
import com.mongodb.gridfs.GridFSDBFile;
import com.mongodb.gridfs.GridFSInputFile;

public class GridTest {
	
	private static final Logger log = LoggerFactory.getLogger(GridTest.class);
	
	public static void main(String[] args) throws FileNotFoundException{
		// 连接到 mongodb 服务
        @SuppressWarnings("resource")
		MongoClient mongoClient = new MongoClient( "localhost" , 27017 );
        @SuppressWarnings("deprecation")
		DB db = mongoClient.getDB("test");
		log.info("成功连接数据库");
	    String collectionName="mongoCollectionTest";  
	    GridFS gridFS = new GridFS(db,collectionName);
	    
	    /* 
         * 2、上传文件 
         */  
        //创建测试文件，mongo 默认存在该文件  
        File file=new File("E:-----------.pdf");  
        FileInputStream fileInputStream=new FileInputStream(file);  
        //创建gridFS文件数据流  
        GridFSInputFile createFile=gridFS.createFile(fileInputStream);  
          
        //设置文件属性  
        createFile.put("filename", "123.pdf");  
        createFile.put("contentType", "application/pdf");  
        createFile.save(); 
        
        /* 
         * 3、根据id查询上传文件 
         */  
        GridFSDBFile findOne= gridFS.findOne(new BasicDBObject("_id",createFile.getId()));  
        System.out.print(findOne);
	}
}

改进后：

import com.mongodb.MongoClient;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.gridfs.GridFSBucket;
import com.mongodb.client.gridfs.GridFSBuckets;
import com.mongodb.client.gridfs.model.GridFSUploadOptions;

import org.bson.Document;
import org.bson.types.ObjectId;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.*;
import java.util.UUID;

public class MongoDBTest {
	private static Logger log = LoggerFactory.getLogger(MongoDbUtil.class);

	private static final class MongoInstance {
		public final static MongoClient client;
		static {
			client = new MongoClient("localhost", 27017);
		}
	}

	public static MongoDatabase getDatabase(String databaseName) {
		return MongoInstance.client.getDatabase(databaseName);
	}

	/**
	 * 上传文件
	 * @param file
	 * @param databaseName
	 * @return
	 */
	public static String uploadFileToGridFS(File file,String databaseName) {
		InputStream in = null;
		String returnId = null;
		String pathName = file.getPath();
		String[] pathNameArray = pathName.split("\\\\");
	    String[] name = pathNameArray[pathNameArray.length-1].split("\\.");
		String filename = name[0];
		String type = name[name.length-1];
		try {
			in = new FileInputStream(file);
			GridFSBucket bucket = GridFSBuckets.create(getDatabase(databaseName));
			GridFSUploadOptions options = new GridFSUploadOptions();
			//设置除filename以为的其他信息
			Document metadata = new Document();
			metadata.append("contentType", type);
			options.metadata(metadata);
			ObjectId fileId = bucket.uploadFromStream(filename+type, in,options);
			returnId = fileId.toHexString();
			log.info("文件上传成功");
		} catch (IOException e) {
			log.info("upload fail:" + e);
		} finally {
			try {
				in.close();
			} catch (IOException e) {
				log.info("close inputstream fail:" + e);
			}
		}
		return returnId;
	}

	/**
	 * 通过objectid和file下载文件
	 * @param objectId
	 * @param file
	 * @param databaseName
	 */
	public static void downloadFile(String objectId, File file,String databaseName) {
		OutputStream os = null;
		try {
			os = new FileOutputStream(file);
			GridFSBucket bucket = GridFSBuckets.create(getDatabase(databaseName));
			bucket.downloadToStream(new ObjectId(objectId), os);
			log.info("文件下载成功");
		} catch (IOException e) {
			log.info("download fail:" + e);
		} finally {
			if (os != null) {
				try {
					os.close();
				} catch (IOException e) {
					log.info("close outputstream fail:" + e);
				}
			}
		}
	}

	/**
	 * 通过objectid删除文件
	 * @param objectId
	 * @param databaseName
	 */
	public static void deleteByObjectId(String objectId,String databaseName) {
		GridFSBucket bucket = GridFSBuckets.create(getDatabase(databaseName));
		bucket.delete(new ObjectId(objectId));
		log.info("文件删除成功");
	}
	
	
	/**
	 * 查询文件
	 * @param databaseName
	 */
	public static List find(String databaseName){
		GridFSBucket bucket = GridFSBuckets.create(getDatabase(databaseName));
		GridFSFindIterable iterable = bucket.find();
		MongoCursor mongoCursor= iterable.iterator();
		List results = new ArrayList(); 
		while(mongoCursor.hasNext()){
			results.add(mongoCursor.next());
		}
		return results;
	}
	
	/**
	 * 查询文件
	 * @param databaseName
	 */
	public static List findBy(String databaseName,Bson filter){
		GridFSBucket bucket = GridFSBuckets.create(getDatabase(databaseName));
		GridFSFindIterable iterable = bucket.find(filter);
		MongoCursor mongoCursor= iterable.iterator();
		List results = new ArrayList(); 
		while(mongoCursor.hasNext()){
			results.add(mongoCursor.next());
		}
		return results;
	}
}
import java.io.File;
import org.junit.Test;

public class MongoGridFSTest 
{
    
    /**
	 * 先上传
	 */
    @Test
	public void upload() {
		File file = new File("C:/Users/Administrator/Desktop/Java持久化之myBatis3.pdf");
		String databaseName = "test";
		String objectId = MongoDbFSUtil.uploadFileToGridFS(file,databaseName);
		System.out.println(objectId);
		System.out.println("文件上传成功");
	}

	/**
	 * 测试下载
	 */
    @Test
	public void download() {
		//System.out.println(objectId);
		File file = new File("D:/1.pdf");
		String databaseName = "test";
		MongoDbFSUtil.downloadFile("594b8298932ed623249dea18", file,databaseName);
		System.out.println("文件下载成功");
	}

	/**
	 * 最后将上传的信息删除
	 */
    @Test
	public void delete() {
		String databaseName = "test";
		MongoDbFSUtil.deleteByObjectId("594b3b53932ed60b043ac4c8",databaseName);
	}
	
	 
    @Test
    public void find(){
    	List results= MongoDbFSUtil.find("test");
    	for(GridFSFile file: results){
    		System.out.println(file.toString());
    	}
    }
    

    @Test
    public void findBy(){
    	Document filter = new Document();
    	filter.append("filename", "深入理解Java虚拟机：JVM高级特性与最佳实践.pdf");
    	List results= MongoDbFSUtil.findBy("test",filter);
    	for(GridFSFile file: results){
    		System.out.println(file.getId());
    	}
    }
    
   
    
   
}