MongoDB程序开发之使用Java驱动

在工作中使用到了MongoDB，平时也看了一些资料，感觉MongoDB官网内develop zone有个不错的manual，很多资料都可以查到，地址如下：http://www.mongodb.org/display/DOCS/Manual

 

另外，本blog主要记录一下使用mongodb java driver来访问数据库的一些总结。

 

 主要是由createMongoInstance()方法完成初始化工作。

protected static final Mongo mongoInstance = createMongoInstance();

private static Mongo createMongoInstance() {
        MongoOptions mo = new MongoOptions();
        mo.socketKeepAlive=true;
        mo.autoConnectRetry = true;
        mo.maxAutoConnectRetryTime=10;
        mo.connectionsPerHost = 40;
        mo.connectTimeout = 20 * 1000;
        mo.socketTimeout = 60 * 1000;
        try {
            if (DatabaseProject.DB_CONFIG.containsKey("mongodb.ips")) {
                return new Mongo(getServerAddrsFromConf("mongodb"),mo);
            }
            return new Mongo(new ServerAddress(DatabaseProject.DB_CONFIG.getString("mongodb.ip"), DatabaseProject.DB_CONFIG.getInt("mongodb.port")),mo);

        } catch (Throwable e) {
            DatabaseProject.LOGGER.error("Failed to init mongodb", e);
            throw new ExceptionInInitializerError(e);
        }
    }

  其中有一些数据库配置直接写在配置文件里了，在MongoJavaDriverDAO中初始化一部分数据：

 

public void insertCollData(){
		//如果该collection不存在则会自动创建
		DBCollection parentcoll = getCollection("ParentColl");
		DBCollection childcoll = getCollection("ChildColl");
		for(int i=0;i<1000;i++){
			DBObject document = new BasicDBObject();
			document.put("intData", 1000+i);
			document.put("longData", System.currentTimeMillis());
			document.put("strData", UUID.randomUUID().toString());
			document.put("doubleData", 1.123+i);
			document.put("createDate", new Date());
			document.put("booleanData", true);
			DBObject innerDoc = new BasicDBObject();
			innerDoc.put("innertype", "string");
			innerDoc.put("innerContent", "string"+i);
			document.put("documentData", innerDoc);
			parentcoll.insert(document);
			DBObject childDocument = new BasicDBObject();
			childDocument.put("parentId", document.get("_id"));
			childDocument.put("createDate", new Date());
			List list = new ArrayList();
			list.add("str" + i%10);
			list.add("str" + i%20);
			list.add(new BasicDBObject("arr"+(i%10),(i%10)));
			list.add(new BasicDBObject("arr"+(i%20),(i%20)));
			childDocument.put("arrays",list);
			childcoll.insert(childDocument);
		}
		System.out.println("ParentColl Count:"+parentcoll.count());
		System.out.println("ChildColl Count:"+childcoll.count());
	}

 其中getCollection方法会获取集合，不存在的话会自动创建一个。getCollection方法如下：

 

public static DBCollection getCollection(String collectionName){
	return getDB().getCollection(collectionName);
}

 现在创建了2个集合ParentColl、ChildColl，并初始化了数据。

查询相关方法：

 

/**
	 * 查询全部数据
	 */
	public void findColl(){
		coll = getCollection("ParentColl");
		DBCursor cur = coll.find();
		while(cur.hasNext()){
	        System.out.println(cur.next());
	    }
		System.out.println("Count:"+coll.count());
	}
	
	/**
	 * 根据ObjectId查询
	 */
	public void findById(String id){
		coll = getCollection("ParentColl");
		DBCursor cur = coll.find(new BasicDBObject("_id", new ObjectId(id)));//直接用string查不出来
		while(cur.hasNext()){
	        System.out.println(cur.next());
	    }
	}
	
	/**
	 * And多条件查询
	 */
	public void findByAndQuery(int intData,long longData){
		coll = getCollection("ParentColl");
		BasicDBObject query = new BasicDBObject();
		query.put("intData", intData);
		query.put("longData", longData);
		System.out.println(coll.findOne(query));
	}
	
	/**
	 * OR多条件查询
	 */
	public void findByORQuery(int lte,int gt,long longData){
		coll = getCollection("ParentColl");
		BasicDBObject query=new BasicDBObject();
		BasicDBObject longdata = new BasicDBObject("longData", longData);
		BasicDBObject intdata = new BasicDBObject("intData", new BasicDBObject().append("$gt", gt).append("$lte",lte));
		BasicDBList cond=new BasicDBList();
		cond.add(longdata);
		cond.add(intdata);
		query.put("$or", cond);
		DBCursor cur = coll.find(query);
		while(cur.hasNext()){
	        System.out.println(cur.next());
	    }
	}
	
	/**
	 * IN查询
	 */
	public void findByINQuery(int value1,int value2){
		coll = getCollection("ParentColl");
		BasicDBObject query=new BasicDBObject();
		BasicDBList cond=new BasicDBList();
		cond.add(value1);
		cond.add(value2);
		query.put("intData",new BasicDBObject("$in", cond));
		DBCursor cur = coll.find(query);
		while(cur.hasNext()){
	        System.out.println(cur.next());
	    }
	}
	
	/**
	 * NOT查询
	 */
	public void findByNotQuery(int value1,int value2){
		coll = getCollection("ParentColl");
		BasicDBObject query=new BasicDBObject();
		BasicDBList cond=new BasicDBList();
		cond.add(value1);
		cond.add(value2);
		query.put("intData",new BasicDBObject("$nin", cond));
		System.out.println("Count:"+coll.find(query).count());
	}
	
	/**
	 * 获取结果集第一条
	 */
	public void fetchFirstQuery(int value1,int value2){
		coll = getCollection("ParentColl");
		BasicDBList cond = new BasicDBList();
		cond.add(value1);
		cond.add(value2);
		BasicDBObject query = new BasicDBObject().append("intData",new BasicDBObject("$nin",cond));
		System.out.println(coll.findOne(query));
	}
	
	/**
	 * 查询文档部分列
	 */
	public void querySomeKey(){
		coll = getCollection("ParentColl");
		DBCursor cur = coll.find(new BasicDBObject(),new BasicDBObject("intData",true));
		while(cur.hasNext()){
	        System.out.println(cur.next());
	    }
	}
	
	/**
	 * 查询内嵌文档
	 */
	public void queryInnerDocument(){
		coll = getCollection("ParentColl");
		BasicDBObject map = new BasicDBObject();
		map.put("innertype","string");
		map.put("innerContent","string0");
		DBCursor cur = coll.find(new BasicDBObject("documentData",map));
		while(cur.hasNext()){
	        System.out.println(cur.next());
	    }
	}
	
	/**
	 * 查询内嵌部分文档
	 */
	public void querySubInnerDocument(){
		coll = getCollection("ParentColl");		
		DBCursor cur = coll.find(new BasicDBObject("documentData.innerContent","string0"));
		while(cur.hasNext()){
	        System.out.println(cur.next());
	    }
	}
	
	/**
	 * 查询分页文档
	 */
	public void queryByPage(int skipNum,int pageNum){
		coll = getCollection("ParentColl");
		DBCursor cur = coll.find().skip(skipNum).limit(pageNum);
		while(cur.hasNext()){
	        System.out.println(cur.next());
	    }
	}
	
	/**
	 * 查询文档某列是否存在
	 */
	public void queryExists(){
		coll = getCollection("ParentColl");
		DBCursor cur = coll.find(new BasicDBObject("longData",new BasicDBObject("$exists",true)));
		while(cur.hasNext()){
			System.out.println(cur.next());
		}
	}
	
	/**
	 * 查询文档排序
	 */
	public void sortDocument(){
		coll = getCollection("ParentColl");
		DBCursor cur = coll.find().sort(new BasicDBObject("intData",-1));//1:asc / -1:desc
		while(cur.hasNext()){
			System.out.println(cur.next());
		}
	}

补充distinct查询：

  /**
	 * 获取根据某元素做distinct查询.
	 */
	   public void distinctKey(){
		coll = getCollection("ParentColl");
		List<String> list = coll.distinct("documentData.innertype");
		for(String str:list){
			System.out.println(str);
		}
	   }

不难发现主要用到BasicDBObject、BasicDBList、DBCursor这三个类。BasicDBObject好比一个map，好比使用json查询中的{} 。BasicDBList是个list，用于or，nin等条件查询。DBCursor用于遍历结果集。其实只要将对应的json查询使用这3个类转化一下，就能写出对应的java代码了。

 

更新相关：

 

/**
	 * 更新文档1
	 */
	public void updateDocument(){
		DB db = getDB();
		//由于mongodb中使用连接池的原因,getLastError()需要再次从连接池中获取连接.
		//保证update操作和getLastError()使用同一个连接.
		db.requestStart();
		coll = db.getCollection("ParentColl");
		WriteResult result = coll.update(new BasicDBObject("intData",1100),new BasicDBObject("$set", new BasicDBObject("booleanData",false)));
		System.out.println("update count:"+result.getN());
		if(result.getLastError().ok()){//获取上次操作结果是否有错误.
			System.out.println("update document success.");
		}else{
			System.out.println(result.getLastError().getErrorMessage());
		}
		db.requestDone();
	}
	
	/**
	 * 更新文档2
	 */
	public void updateMultiDocument(){
		DB db = getDB();
		db.requestStart();
		coll = db.getCollection("ParentColl");
		//第三个参数:如果没有该文档是否创建,第四个参数:是否更新全部匹配条件的文档.
		WriteResult result = coll.update(new BasicDBObject("booleanData",false),new BasicDBObject("$set", new BasicDBObject("booleanData",true)),false,true);
		System.out.println("update count:"+result.getN());
		if(result.getLastError().ok()){//获取上次操作结果是否有错误.
			System.out.println("update document success.");
		}else{
			System.out.println(result.getLastError().getErrorMessage());
		}
		db.requestDone();
	}

 注意requestStart、requestDone方法保证使用同一个数据库连接。WriteResult记录更新结果。 

 

索引相关：

 

/**
	 * 创建唯一索引
	 */
	public void createIndexes(){
		coll = getCollection("ParentColl");
		BasicDBObject index = new BasicDBObject();
		index.put("intData",1);//1:asc / -1:desc
		index.put("unique",true);//唯一索引
		coll.createIndex(index);
	}
	
	/**
	 * 查询索引信息
	 */
	public void getIndexes(){
		coll = getCollection("ParentColl");
		List<DBObject> indexInfo = coll.getIndexInfo();
		System.out.println(indexInfo);
	}
	
	/**
	 * 删除索引信息
	 */
	public void dropIndexes(){
		coll = getCollection("ParentColl");
		//删除的索引必须跟创建的索引名称\排序\是否唯一都相同才能删除
		BasicDBObject index = new BasicDBObject();
		index.put("intData",1);
		index.put("unique",true);
		coll.dropIndex(index);
	}

 对于文档可能还会对数组操作：

 

/**
	 * 取出文档中的数组
	 */
	public void queryArray(){
		coll = getCollection("ChildColl");
		DBCursor cur = coll.find(new BasicDBObject(),new BasicDBObject("arrays",1));
		while(cur.hasNext()){
			BasicDBObject bo = (BasicDBObject)cur.next();
			List<BasicDBObject> list = (List<BasicDBObject>)bo.get("arrays");
			System.out.println(list.toString());
		}
	}
	
	/**
	 * 查询数组内是否包含某元素
	 */
	public void queryElementInArray(){
		coll = getCollection("ChildColl");
		BasicDBObject query = new BasicDBObject();
		BasicDBObject obj = new BasicDBObject();
		obj.put("arr0",0);
		query.put("arrays", new BasicDBObject("$elemMatch",obj));
		DBCursor cur = coll.find(query);
		while(cur.hasNext()){
			System.out.println(cur.next());
		}
	}
	
	/**
	 * 数组内包含元素的值
	 */
	public void queryElementArray(){
		coll = getCollection("ChildColl");
		BasicDBObject obj = new BasicDBObject();
		obj.put("arrays", "str0");
		obj.put("arrays.arr0",0);
		obj.put("arrays.arr10",10);
		DBCursor cur = coll.find(obj);
		while(cur.hasNext()){
			System.out.println(cur.next());
		}
	}
	
	/**
	 * push(pushAll) array element
	 */
	public void pushElementInArray(String _id){
		DB db = getDB();
		db.requestStart();
		coll = getCollection("ChildColl");
		//WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$push",new BasicDBObject("arrays",new BasicDBObject("arr99","99"))));
		List<BasicDBObject> list=new ArrayList<BasicDBObject>();
		list.add(new BasicDBObject("arr99",99));
		list.add(new BasicDBObject("arr100",100));
		WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pushAll",new BasicDBObject("arrays",list)));
		System.out.println("update count:"+result.getN());
		if(result.getLastError().ok()){
			System.out.println("update document success.");
		}else{
			System.out.println(result.getLastError().getErrorMessage());
		}
		db.requestDone();
	}
	
	/**
	 * pull(pullAll) array element
	 */
	public void pullElementInArray(String _id){
		DB db = getDB();
		db.requestStart();
		coll = getCollection("ChildColl");
		List<BasicDBObject> list=new ArrayList<BasicDBObject>();
		list.add(new BasicDBObject("arr99",99));
		list.add(new BasicDBObject("arr100",100));
		//WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pull",new BasicDBObject("arrays",new BasicDBObject("arr100",100))));
		WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pullAll",new BasicDBObject("arrays",list)));
		System.out.println("update count:"+result.getN());
		db.requestDone();
	}
	
	/**
	 * pop array element(1,last;-1,first)
	 */
	public void popElementInArray(String _id){
		coll = getCollection("ChildColl");
		WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pop",new BasicDBObject("arrays",-1)));//1,last;-1,first
		System.out.println("update count:"+result.getN());
	}
	
	/**
	 * addToSet And Each array element
	 */
	public void addToSetAndEachElementInArray(String _id){
		coll = getCollection("ChildColl");
		List list = new ArrayList();
		list.add("str0");
		list.add("str1");
		list.add(new BasicDBObject("arr99",99));
		WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$addToSet",new BasicDBObject("arrays",new BasicDBObject("$each",list))));//1,last;-1,first
		System.out.println("update count:"+result.getN());
	}

/**
	 * 按数组位置更新文档(查询条件需要包含更新内容，$为数组位置占位符，只更新匹配到的第一个文档.)
	 */
	public void updatePositionInArray(String _id){
		coll = getCollection("ChildColl");
		WriteResult result = coll.update(new BasicDBObject("arrays.arr0", 100),new BasicDBObject("$set",new BasicDBObject("arrays.$.arr0",101)));
		System.out.println("update count:"+result.getN());
	}

   以上都是一些基本的查询、更新操作，当然还有一些如map reduce和关联查询等复杂的方法，我将另写一篇blog总结一下。

 

参考文献包括：《mongodb权威指南》、《mongodb管理与开发精要》，另外文章开头提到的MongoDB官网内的develop zone也是很不错的资料来源。

PS：

mongodb driver在线API文档： http://api.mongodb.org/java/2.8.0/ （目前是2.8.0）