Java 程序保存图片，文件到 MongoDB 数据库

MongoDB 与传统的关系型数据库一样能保存图片或文件到数据库，不过操作的方法有点特殊，它借助了 GridFS 来保存文件到数据库，比如图片，视频，音乐等文件都可以。关于GridFS 的介绍，可以参考这里:http://docs.mongodb.org/manual/core/gridfs/, 一般来说对文件册操作主要包括以下几方面:
1. 保存文件到mongoDB.
2. 获取所有的文件列表
3. 从MongoDB 中得到文件，并输出保存到硬盘上
4. 从MongoDB中删除数据

1. 保存文件到mongoDB.

String newFileName = "yihaomen-java-image"; File imageFile = new File("c:\\images\\Winter.jpg"); // create a "photo" namespace GridFS gfsPhoto = new GridFS(db, "photo"); // get image file from local drive GridFSInputFile gfsFile = gfsPhoto.createFile(imageFile); // set a new filename for identify purpose gfsFile.setFilename(newFileName); // save the image file into mongoDB gfsFile.save();

2. 从MongoDB 中得到文件，并输出保存到硬盘上

GridFS gfsPhoto = new GridFS(db, "photo"); DBCursor cursor = gfsPhoto.getFileList(); while (cursor.hasNext()) {     System.out.println(cursor.next()); }

3. 从MongoDB 中得到文件，并输出保存到硬盘上

GridFS gfsPhoto = new GridFS(db, "photo"); GridFSDBFile imageForOutput = gfsPhoto.findOne(newFileName); // save it into a new image file imageForOutput.writeTo("c:\\images\\Winter-From-Mongodb.jpg");

4. 删除文件数据

String newFileName = yiahomen-java-image"; GridFS gfsPhoto = new GridFS(db, "photo"); gfsPhoto.remove(gfsPhoto.findOne(newFileName));

整个测试代码如下:

package com.yihaomen.mongodb.process.image;   import java.io.File; import java.io.IOException; import java.net.UnknownHostException;   import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.DBCursor; import com.mongodb.Mongo; import com.mongodb.MongoException; import com.mongodb.gridfs.GridFS; import com.mongodb.gridfs.GridFSDBFile; import com.mongodb.gridfs.GridFSInputFile;   public class MongoDBImage {           public static void main(String[] args) {                 try {                Mongo mongo = new Mongo("localhost", 27017);             DB db = mongo.getDB("yihaomen");                        DBCollection collection = db.getCollection("MyImage");             String newFileName = "yihaomen-java-image";             File imageFile = new File("c:\\images\\Winter.jpg");             // create a "photo" namespace             GridFS gfsPhoto = new GridFS(db, "photo");             // get image file from local drive             GridFSInputFile gfsFile = gfsPhoto.createFile(imageFile);             // set a new filename for identify purpose             gfsFile.setFilename(newFileName);             // save the image file into mongoDB             gfsFile.save();             // print the result             DBCursor cursor = gfsPhoto.getFileList();             while (cursor.hasNext()) {                 System.out.println(cursor.next());             }                // get image file by it's filename             GridFSDBFile imageForOutput = gfsPhoto.findOne(newFileName);             // save it into a new image file             imageForOutput.writeTo("c:\\images\\Winter-From-Mongodb.jpg");             // remove the image file from mongoDB             gfsPhoto.remove(gfsPhoto.findOne(newFileName));             System.out.println("Done");         } catch (UnknownHostException e) {             e.printStackTrace();         } catch (MongoException e) {             e.printStackTrace();         } catch (IOException e) {             e.printStackTrace();         }     } }

From：一号门