Spring Data MongoDB：使用GridFS保存二进制文件

在MongoDB中，可以使用GridFS保存二进制文件。本文介绍如何使用GridFsTemplate保存和读取图片文件。

1. GridFS - 保存（使用Spring注解方式）

import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.data.mongodb.config.AbstractMongoConfiguration;import org.springframework.data.mongodb.gridfs.GridFsTemplate;import com.mongodb.Mongo;import com.mongodb.MongoClient;/** * Spring MongoDB configuration file * */@Configurationpublic class SpringMongoConfig extends AbstractMongoConfiguration{    @Bean    public GridFsTemplate gridFsTemplate() throws Exception {        return new GridFsTemplate(mongoDbFactory(), mappingMongoConverter());    }    @Override    protected String getDatabaseName() {        return "yourdb";    }    @Override    @Bean    public Mongo mongo() throws Exception {        return new MongoClient("127.0.0.1");    }}

import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.io.InputStream;import org.springframework.context.ApplicationContext;import org.springframework.context.annotation.AnnotationConfigApplicationContext;import org.springframework.data.mongodb.gridfs.GridFsOperations;import com.mkyong.config.SpringMongoConfig;import com.mongodb.BasicDBObject;import com.mongodb.DBObject;/** * GridFs example * * @author zong * */public class GridFsAppStore {    public static void main(String[] args) {    ApplicationContext ctx =                     new AnnotationConfigApplicationContext(SpringMongoConfig.class);    GridFsOperations gridOperations =                      (GridFsOperations) ctx.getBean("gridFsTemplate");    DBObject metaData = new BasicDBObject();    metaData.put("extra1", "anything 1");    metaData.put("extra2", "anything 2");    InputStream inputStream = null;    try {        inputStream = new FileInputStream("/Users/mkyong/Downloads/testing.png");        gridOperations.store(inputStream, "testing.png", "image/png", metaData);    } catch (FileNotFoundException e) {        e.printStackTrace();    } finally {        if (inputStream != null) {            try {                inputStream.close();            } catch (IOException e) {                e.printStackTrace();            }        }    }        System.out.println("Done");    }}

使用MongoDB控制台查看保存的文件：

> show dbsyourdb  0.203125GB> use yourdbswitched to db yourdb> show collectionsfs.chunksfs.filessystem.indexes> db.fs.files.find(){ "_id" : ObjectId("51641c5630045c9b3db35afc"), "chunkSize" : NumberLong(262144),"length" : NumberLong(4238), "md5" : "9969527cd95a5a573f15e953f0036800", "filename" : "testing.png","contentType" : "image/png", "uploadDate" : ISODate("2013-04-09T13:49:10.104Z"),"aliases" : null, "metadata" : { "extra1" : "anything 1", "extra2" : "anything 2" } }>> db.fs.chunks.find(){ "_id" : ObjectId("51641c5630045c9b3db35afd"),"files_id" : ObjectId("51641c5630045c9b3db35afc"), "n" : 0,"data" : BinData(0,"/9j/4AAQSkZJRgABAgAAZ......EQH/9k=") }

图片信息保存在fs.files，图片的二进制流保存在fs.chunks，通过_id和files_id关联。

2. GridFS - 读取（使用xml方式）

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xmlns:mongo="http://www.springframework.org/schema/data/mongo"    xsi:schemaLocation="http://www.springframework.org/schema/data/mongo       http://www.springframework.org/schema/data/mongo/spring-mongo.xsd       http://www.springframework.org/schema/beans       http://www.springframework.org/schema/beans/spring-beans.xsd">    <mongo:db-factory id="mongoDbFactory" dbname="yourdb" />    <mongo:mapping-converter id="converter" />    <bean name="gridFsTemplate"        class="org.springframework.data.mongodb.gridfs.GridFsTemplate">        <constructor-arg ref="mongoDbFactory" />        <constructor-arg ref="converter" />    </bean></beans>

import java.io.IOException;import java.util.List;import org.springframework.context.ApplicationContext;import org.springframework.context.support.GenericXmlApplicationContext;import org.springframework.data.mongodb.core.query.Criteria;import org.springframework.data.mongodb.core.query.Query;import org.springframework.data.mongodb.gridfs.GridFsOperations;import com.mongodb.BasicDBObject;import com.mongodb.DBObject;import com.mongodb.gridfs.GridFSDBFile;/** * GridFs example * * @author zong * */public class GridFsAppRead {    public static void main(String[] args) {    ApplicationContext ctx =              new GenericXmlApplicationContext("SpringConfig.xml");    GridFsOperations gridOperations =              (GridFsOperations) ctx.getBean("gridFsTemplate");    List<GridFSDBFile> result = gridOperations.find(               new Query().addCriteria(Criteria.where("filename").is("testing.png")));    for (GridFSDBFile file : result) {        try {            System.out.println(file.getFilename());            System.out.println(file.getContentType());            //save as another image            file.writeTo("/Users/mkyong/Downloads/new-testing.png");        } catch (IOException e) {            e.printStackTrace();        }    }    System.out.println("Done");    }}