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
	Set cols = 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(List mediaEntityList) {
	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");
	ArrayList tagList = (ArrayList) obj.get("tag");	// tag
	ArrayList keywordList = (ArrayList)obj.get("keyword");	// keyword
	ArrayList copyrightList = (ArrayList)obj.get("copyright");	// copyright
	
	
	MediaEntity mediaEntity = new MediaEntity();
	
	mediaEntity.setId(id);
	
	// tag
	for(int j=0; j actorsObjList = (ArrayList)obj.get("actors");	// actors
	for(int j=0; j directorObjList = (ArrayList)obj.get("director");	// director
	for(int j=0; j 100) {
	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;
	}