Java 连接MongoDB package mymaven;import java.net.UnknownHostException;import java.util.Set;import com.mongodb.BasicDBObject;import com.mongodb.DB;import com.mongodb.DBCollection;import com.mongodb.DBCursor;import com.mongodb.DBObject;impor

Java 连接MongoDB

package mymaven;

import java.net.UnknownHostException;

import java.util.Set;

import com.mongodb.BasicDBObject;

import com.mongodb.DB;

import com.mongodb.DBCollection;

import com.mongodb.DBCursor;

import com.mongodb.DBObject;

import com.mongodb.Mongo;

import com.mongodb.MongoException;

public class Test {

/**

* @author ithomer.net

* @datetime 2013-11-11

*/

public static void main(String[] args) throws UnknownHostException, MongoException {

Mongo mongo = new Mongo("172.27.9.104", 27017);// 连接数据库

DB db = mongo.getDB("mytestdb");// 数据库

Setcols = db.getCollectionNames();// 获取数据库中所有的集合(类似于获取关系数据库中的表)

// 打印出数据库中的集合，这里应当为null

for (String s : cols) {

System.out.println(s);

}

DBCollection collection = db.getCollection("mytestcoll");// 创建一个集合

collection.drop();// 删除集合，插入数据时自动重建

BasicDBObject obj = new BasicDBObject();// 初始化一个基本DB对象，插入数据库的就是DB对象

obj.put("from", "blog.ithomer.net");// 放入几个键值对

obj.put("to", "forum.ithomer.net");

obj.put("subject", "ithomer.net");

collection.insert(obj);// 插入对象

DBObject dbobj = collection.findOne();// 查看一条记录，findOne()=find().limit(1);

System.out.println(dbobj);// 打印出刚才插入的数据

// 插入10条{ranking:i}的数据

for (int i = 0; i < 10; i++) {

collection.insert(new BasicDBObject().append("ranking", i));

}

System.out.println("count: " + collection.getCount());// 打印集合中的数据总数

DBCursor cursor = collection.find();// 然后我们使用这个游标来遍历集合

while (cursor.hasNext()) {

System.out.println(cursor.next());

}

// 简单的条件查询，查询ranking为1的记录

BasicDBObject query = new BasicDBObject();

query.put("ranking", 1);

cursor = collection.find(query);

System.out.println("collection find({\"ranking\":1}):");

while (cursor.hasNext()) {

System.out.println(cursor.next());

}

// 复杂的条件查询，查询ranking大于等于5小于9的记录

query = new BasicDBObject();

query.put("ranking", new BasicDBObject("$gte", 5).append("$lt", 9));

cursor = collection.find(query);

System.out.println("collection find({\"ranking\":[5-9)}):");

while (cursor.hasNext()) {

System.out.println(cursor.next());

}

//mongo.dropDatabase("mytestdb");// 最后删除我们的测试数据库

}

}

运行结果：

mytestcoll

system.indexes

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10107"} , "from" : "blog.ithomer.net" , "to" : "forum.ithomer.net" , "subject" : "ithomer.net"}

count: 11

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10107"} , "from" : "blog.ithomer.net" , "to" : "forum.ithomer.net" , "subject" : "ithomer.net"}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10108"} , "ranking" : 0}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10109"} , "ranking" : 1}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010a"} , "ranking" : 2}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010b"} , "ranking" : 3}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010c"} , "ranking" : 4}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010d"} , "ranking" : 5}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010e"} , "ranking" : 6}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010f"} , "ranking" : 7}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10110"} , "ranking" : 8}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10111"} , "ranking" : 9}

collection find({"ranking":1}):

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10109"} , "ranking" : 1}

collection find({"ranking":[5-9)}):

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010d"} , "ranking" : 5}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010e"} , "ranking" : 6}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010f"} , "ranking" : 7}

{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10110"} , "ranking" : 8}

源码下载(maven)

mongodb数组示例：

@SuppressWarnings("unchecked")

public static void loadMediaTags(ListmediaEntityList) {

mediaEntityList.clear();

try {

Mongo mongo = new Mongo(CosineCluster.gMongo_HOST, CosineCluster.gMongo_PORT);

DB db = mongo.getDB(CosineCluster.gMongo_DB);

DBCollection collection = db.getCollection(CosineCluster.gMongo_Coll_Media);

DBCursor cursor = collection.find();

int index = 0;

long startTime = System.currentTimeMillis();

while(cursor.hasNext()){

BasicDBObject obj = (BasicDBObject) cursor.next();

long id = obj.getLong("_id");

ArrayListtagList = (ArrayList) obj.get("tag");// tag

ArrayListkeywordList = (ArrayList)obj.get("keyword");// keyword

ArrayListcopyrightList = (ArrayList)obj.get("copyright");// copyright

MediaEntity mediaEntity = new MediaEntity();

mediaEntity.setId(id);

// tag

for(int j=0; jactorsObjList = (ArrayList)obj.get("actors");// actors

for(int j=0; j directorObjList = (ArrayList)obj.get("director");// director

for(int j=0; j100) {

break;

}

System.out.println(index + " --- mediaEntity : " + mediaEntity.toString());

}

long costTime = System.currentTimeMillis() - startTime;

System.out.println("load data costTime = " + index + "; costTime = " + costTime/1000f);

} catch (Exception e) {

e.printStackTrace();

}

}

public static int getTagInt(String tag) {

int tagIntId = -1;

try {

MongoClient mongo = new MongoClient(CosineCluster.gMongo_HOST, CosineCluster.gMongo_PORT);

DB db = mongo.getDB(CosineCluster.gMongo_DB);

DBCollection tagmapCollection = db.getCollection("recommend_tag_map");

DBCursor cursor = tagmapCollection.find(new BasicDBObject("name", tag));

if(cursor == null || cursor.toArray().size() <= 0) {// 处理小于2或n的映射关键字，下同

return tagIntId;

}

DBObject obj = cursor.toArray().get(0);

String name = tag;

tagIntId = (Integer) obj.get("id");

int num = (Integer) obj.get("num");

mongo.close();

} catch (UnknownHostException e) {

e.printStackTrace();

}

return tagIntId;

}

public static int getActorInt(String actor) {

int actorIntId = -1;

try {

MongoClient mongo = new MongoClient(CosineCluster.gMongo_HOST, CosineCluster.gMongo_PORT);

DB db = mongo.getDB(CosineCluster.gMongo_DB);

DBCollection tagmapCollection = db.getCollection("recommend_actor_map");

DBCursor cursor = tagmapCollection.find(new BasicDBObject("name", actor));

if(cursor == null || cursor.toArray().size() <= 0) {

return actorIntId;

}

DBObject obj = cursor.toArray().get(0);

String name = actor;

actorIntId = (Integer) obj.get("id");

int num = (Integer) obj.get("num");

mongo.close();

} catch (UnknownHostException e) {

e.printStackTrace();

}

return actorIntId;

}

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