MongoDB Java 连接
Java 连接MongoDBpackage 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<String> 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<MediaEntity> 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<String> tagList = (ArrayList<String>) obj.get("tag"); // tag
ArrayList<String> keywordList = (ArrayList<String>)obj.get("keyword"); // keyword
ArrayList<Integer> copyrightList = (ArrayList<Integer>)obj.get("copyright"); // copyright
MediaEntity mediaEntity = new MediaEntity();
mediaEntity.setId(id);
// tag
for(int j=0; j<tagList.size(); j++) {
mediaEntity.addTag(tagList.get(j));
int tagId = getTagInt(tagList.get(j));
mediaEntity.addTag(tagId);
}
// actors
ArrayList<DBObject> actorsObjList = (ArrayList<DBObject>)obj.get("actors"); // actors
for(int j=0; j<actorsObjList.size(); j++) {
mediaEntity.addActor((String) actorsObjList.get(j).get("name"));
int actorId = getActorInt((String)actorsObjList.get(j).get("name"));
mediaEntity.addActor(actorId);
}
// director
ArrayList<DBObject> directorObjList = (ArrayList<DBObject>)obj.get("director"); // director
for(int j=0; j<directorObjList.size(); j++) {
mediaEntity.addDirector((String) directorObjList.get(j).get("name"));
int directorId = getDirectorInt((String) directorObjList.get(j).get("name"));
mediaEntity.addDirector(directorId);
}
// keyword
for(int j=0; j<keywordList.size(); j++) {
mediaEntity.addKeyword(keywordList.get(j));
int keywordId = getKeywordInt(keywordList.get(j));
mediaEntity.addKeyword(keywordId);
}
// copyright
for(int j=0; j<copyrightList.size(); j++) {
mediaEntity.addCopyright(copyrightList.get(j));
}
mediaEntityList.add(mediaEntity);
index++;
if(index > 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;
}
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